Will a 6 pinion planet gear work in 4L65E

[MyM8V8]

Hi,

We are building a new box for next year and are considering installing a new 6 pinion planet gear in place of the stock 5 gear one to even out the ratios.

Is it possible to reprogramme the gear ratios to suit this set up without any issues?

Thanks in anticipation. Gareth.

[joecar]

Gareth,

Do you mean the 6-pinion gearset from PATC (find "6 pinion" on this page): www.transmissioncenter.net/4l60e.htm (http://www.transmissioncenter.net/4l60e.htm)

My understanding is that the gearset fits the 4L65E (4L65E is interchangeable with 4L60E)... but, to be sure contact PATC and ask them directly.

The PCM transmission calibration has editable gear ratios, see D1201-2 and D4601... set these to 1st=2.84 and 2nd=1.56.

I do like the closer ratios, you don't need as loose a stall converter as you do with the stock ratios.

[N0DIH]

$1100+....owch....

[MyM8V8]

Gareth,

Do you mean the 6-pinion gearset from PATC (find "6 pinion" on this page): www.transmissioncenter.net/4l60e.htm (http://www.transmissioncenter.net/4l60e.htm)

My understanding is that the gearset fits the 4L65E (4L65E is interchangeable with 4L60E)... but, to be sure contact PATC and ask them directly.

The PCM transmission calibration has editable gear ratios, see D1201-2 and D4601... set these to 1st=2.84 and 2nd=1.56.

I do like the closer ratios, you don't need as loose a stall converter as you do with the stock ratios.

Yes, Joe, that's the one. I suppose the stall is also affected by where the cam is as well, but there is a definite advantage to having a tighter stall when you have a dual purpose truck, i.e. street/strip.


What I was really getting at was; with the gearbox ratio calibration applet, I recall vaguely there were some issues with the software and calculations and I did have problems using it to (unsuccessfuly) recalibrate my speedo from kmh to mph.

It would be handy to know if there are any guys who have used it to change the ratios successfully in similar circumstances. What worried me was on the PATC site it referred to certian setups throwing ratio codes. So I thought I'd just check here first.

As NOD1H has said, it's a lot of money if it don't work, but if it does, it could be the best upgrade in the box (Well apart from a 300m input drum).

[joecar]

You mean the Speedo Calculator... the speedo comes from the VSS signal which is taken from the reluctor on the trans output shaft... changing the trans internal gear ratios doesn't change VSS relationship to the output shaft...

I would just manually calculate and edit all the tables that are affected by a VSS relationship change.

Someone here (slow67) is running a 4L80E on a 4L60E calibration (to keep the TCC locked at zero throttle)... it seems he did not edit in the 4L80E gear ratios (2.48, 1.48, 1.00, 0.75) so he got some codes: showthread.php?t=11975 (http://forum.efilive.com/showthread.php?t=11975)

It will throw codes if the calibration is not edited with the new ratios... the PCM computes in each gear what the RPM:VSS ratio should be based on the current gear ratio and whether the TCC is locked... if it does not agree then a code is set.

You may have to edit the 1->2, 2->1, 2->3, 3->2 shift tables (PT and WOT) since 1st and 2nd gear are now numerically lower (the max (engine redline) MPH in 1st and 2nd is now higher).

It's a lot of money, but you get various benefits: it's stronger than the 4 or 5 pinion sets, it gives closer gear ratio spacing, allows you to use a tighter stall converter, and others.

[MyM8V8]

Hi Joe,

Wondered if you could help. I am trying to sort out a heavy duty input drum assembly from PATC and I'm not quite sure which one I need?

There are two available, one for 2007 up and one for before. The difference is the reluctor for the speed sensor on the shaft.

I have a 2005 in the ute and the one coming from Holmart is a 2006YOM.

They are asking which color case connector I have and I dont; know.

Cheers if you can help.

[ScarabEpic22]

Interesting, that 6 pinion gearset looks really promising. Im going to ask the guys in the TBSS world if it might be a better way to lower E.T.s. Wish it had a higher (numerically lower) OD gear than .70, Id love a .65 or .60 OD gear with these 4.10 gears. Kills the mileage on the hwy when you're spinning about 2600rpms going 75mph. My regular TB with 3.73s spins about 2300 at 75...

[MyM8V8]

Interesting, that 6 pinion gearset looks really promising. Im going to ask the guys in the TBSS world if it might be a better way to lower E.T.s. ...


They're claiming up to 3/10ths.

[joecar]

Hi Joe,

Wondered if you could help. I am trying to sort out a heavy duty input drum assembly from PATC and I'm not quite sure which one I need?

There are two available, one for 2007 up and one for before. The difference is the reluctor for the speed sensor on the shaft.

I have a 2005 in the ute and the one coming from Holmart is a 2006YOM.

They are asking which color case connector I have and I dont; know.

Cheers if you can help.The input drum/shaft with the reluctor teeth is for the 4L65E/4L70E variants that have the ISS (input speed sensor)...

the stator support shaft has to allow space for the reluctor teeth;

If you don't have the ISS then you want the other input drum...

The electrical connector on the case...?
If you look at it you should be able to see what color it is...
(on RHS of case, on flat "wing" above the pan (rearward of where dipstick tube fits)...
it is most likely Grey... but I don't have any diagrams later than 2005.

[MyM8V8]

The input drum/shaft with the reluctor teeth is for the 4L65E/4L70E variants that have the ISS (input speed sensor)...

the stator support shaft has to allow space for the reluctor teeth;

If you don't have the ISS then you want the other input drum...

The electrical connector on the case...?
If you look at it you should be able to see what color it is...
(on RHS of case, on flat "wing" above the pan (rearward of where dipstick tube fits)...
it is most likely Grey... but I don't have any diagrams later than 2005.


You are right. It is grey. I just need to find out whether I have ISS.

Once again. Thanks Joe. :cheers:

[joecar]

I'm wondering... you might be able to use the reluctor input drum/shaft if you use the stator support that goes with it... check with PATC if the ISS style stator support works in a non-ISS transmission... if it does, then you would be able use that input drum/shaft.

Ask them if both parts fit into a non-ISS 4L60E/4L65E.

[MyM8V8]

I'm wondering... you might be able to use the reluctor input drum/shaft if you use the stator support that goes with it... check with PATC if the ISS style stator support works in a non-ISS transmission... if it does, then you would be able use that input drum/shaft.

Ask them if both parts fit into a non-ISS 4L60E/4L65E.

Hi Joe,

I just got back from visiting SEMA and brought the parts back with me, everything is sorted after being looked over by your government people (they left a note in my cases to say they checked everything too - nice).

The 6 pinion gearset looks like a nice piece. The drum aasembly I got is the later one which is strengthened and the shaft hardened, the shaft is the later reluctor shaft. I think these parts are from the 4L70E, and although I dont have ISS on mine, the new stator support shaft sorts this. I also bought some other good parts to build the box.

I hope it all works, although the expert consensus is that I should've gone with a 4L80E for the 1/4 mile.

Cheers Gareth

[joecar]

Hi Gareth,

Hey cool... there's no feeling like having new parts in your possession...:cheers:
the next best feeling is having your engine or transmission apart in pieces and looking over everything in detail...:cheers:

Ok, so the new stator support allows the later/strengthen/4L70E input shaft to fit in the 4L6xE... I'm filing that for future use.


There's quite a few people running strengthen 4L60E's that are doing just fine... Sure, the 4L80E/4L85E is designed to be heavier duty, but it would still need to be strengthened... the 4L6xE is a simpler box compared to the 4L80E, and simplicity usually always wins.

I think that the closer spacing between 1st and 2nd will remove a lot of induced stress; and the 6 pinion carrier, besides being stronger, spreads the load more evenly.


Please post lots of pics of your parts when possible... :)

Cheers mate
:cheers:

[joecar]

Gareth,

Can you please do this for me when you can: count the teeth on the sun gear, ring gear, and one pinion.

Thanks, I appreciate it.

[MyM8V8]

Hi Gareth,

Hey cool... there's no feeling like having new parts in your possession...:cheers:
the next best feeling is having your engine or transmission apart in pieces and looking over everything in detail...:cheers:

Ok, so the new stator support allows the later/strengthen/4L70E input shaft to fit in the 4L6xE... I'm filing that info away.

There's quite a few people running strengthen 4L60E's that are doing just fine... Sure, the 4L80E/4L85E is designed to be heavier duty, but it would still need to be sstrengthened... the 4L6xE is a simpler box compared to the 4L80E, and simplicity always wins.

I think that the closer spacing between 1st and 2nd will remove a lot of induced stress; and the 6 pinion carrier, besides being stronger, spreads the load more evenly.


Please post lots of pics of your parts when possible... :)

Cheers mate
:cheers:


Ok I'll post up when I take some pics.

What I have been told is that although the parts will help the box to take extra torque/hp, (as the vendors advertise), it is how that torque/hp is applied that is the problem, and you can't get much worse than kicking it's ar** out of the hole on a 1/4 mile. (They say the parts I have got are supposed to take 600 ft lbs - but not how?)

Anyway, we'll build this and give it a shot and let you know what happens, but I have been told the T42 tune has to be absolutely spot on for it all to go together.

Also been told that whatever you do with a 4L65, the computer is the limitation and it would be a good idea to look at installing the sonnax vacuum kit to take it out of the equation (you have to fool it into thinking it is doing the job though).

:cheers:

[MyM8V8]

gareth,

can you please do this for me when you can: Count the teeth on the sun gear, ring gear, and one pinion.

Thanks, i appreciate it.

38,70,16.

[joecar]

38,70,16.Cool, thanks, those are important to know...:cheers:

From those I calculate 1st gear at 2.8421...

I misplaced the tooth counts for the other gearset...

Do you also happen to know the teeth count for:
- OEM front/input gearset,
- OEM rear/reaction gearset,

Thanks I appreciate it.

[joecar]

Oh, I think I found them:

OEM front gearset tooth count:
sun = 34
ring = 70
planet = 18

OEM rear rgearset tooth count:
sun = 34
ring = 78
planet = 22

[MyM8V8]

Oh, I think I found them:

OEM front gearset tooth count:
sun = 34
ring = 70
planet = 18

OEM rear rgearset tooth count:
sun = 34
ring = 78
planet = 22

Those are for 4L65E with 5 pinion gear?

[joecar]

Oh, I think I found them:

OEM front gearset tooth count:
sun = 34
ring = 70
planet = 18

OEM rear rgearset tooth count:
sun = 34
ring = 78
planet = 22
Those are for 4L65E with 5 pinion gear?
It seems to me that those are for OEM 4-pinon and OEM 5-pinion gearsets.

Partial sanity check:
sun + 2*pinion = ring
34 + 2*18 = 70
34 + 2*22 = 78

[joecar]

OEM front/input gearset tooth count:
sun = 34
ring = 70
planet = 18
(check 34+2*18=70)
sun:ring velocity ratio (mechanical advantage) = 70/34 = 2.0588

OEM rear/reaction gearset tooth count:
sun = 34
ring = 78
planet = 22
(check 34+2*22=78)
sun:ring velocity ratio (mechanical advantage) = 78/34 = 2.2941


1st gear:

front gearset only:
sun = input
ring = held
carrier = output

In the matrix below:
0 = held stationary relative to case
-1 = reverse rotation


Represent this using a 1x3 matrix:
[ sun ring carrier ]

[ 2.0588 -1 0 ]

[ 3.0588 0 1 ] (added 1 to all elements)

input = 3.0588, output = 1
So 1st gear ratio is 3.0588.

2nd gear:

front carrier drives rear ring and front ring drives rear carrier simulatenously.

front gearset:
sun = input
ring = rear carrier
carrier = rear ring = output

rear gearset:
sun = held
ring = front carrier = output
carrier = front ring


Represent this as 2x3 Matrix:
[ [ sunfront ringfront carrierfront ]
[ sunrear ringrear carrierrear ]
]

[ [ 2.0588 -1 0 ]
[ 2.2941 -1 0 ]
]

[ [ 3.0588 0 1 ] (added 1 to row)
[ 0 -3.2941 -2.2941 ] (subtracted 2.2941 from row)
]

[ [ 4.3921 0 1.4359 ] (multiplied row by 1.4359 from next row)
[ 0 1.4359 1 ] (divided row by -2.2941)
]

[ [ 1.3333 0 0.4359 ] (multiplied row by 0.4359/1.4359)
[ 0 1.4359 1 ]
]

[ [ 2.3333 1 1.4359 ] (added 1 to row)
[ 0 1.4359 1 ]
]

[ [ 1.6250 0.6964 1 ] (divided both rows by 1.4359)
[ 0 1 0.6964 ]
]

input = 1.6250, output = 1
So 2nd gear ratio is 1.6250.

[joecar]

PATC 6-pinion front/input gearset tooth count:
sun = 38
ring = 70
planet = 16
(check 38+2*16=70)
sun:ring velocity ratio (mechanical advantage) = 70/38 = 1.8421

OEM rear/reaction gearset tooth count:
sun = 34
ring = 78
planet = 22
(check 34+2*22=78)
sun:ring velocity ratio (mechanical advantage) = 78/34 = 2.2941


1st gear:

front gearset only:
sun = input
ring = held
carrier = output

In the matrix below:
0 = held stationary relative to case
-1 = reverse rotation


Represent this using a 1x3 matrix:
[ sun ring carrier ]

[ 1.8421 -1 0 ]

[ 2.8421 0 1 ] (added 1 to all elements)

input = 2.8421, output = 1
So 1st gear ratio is 2.8421.

2nd gear:

front carrier drives rear ring and front ring drives rear carrier simulatenously.

front gearset:
sun = input
ring = rear carrier
carrier = rear ring = output

rear gearset:
sun = held
ring = front carrier = output
carrier = front ring


Represent this as 2x3 Matrix:
[ [ sunfront ringfront carrierfront ]
[ sunrear ringrear carrierrear ]
]

[ [ 1.8421 -1 0 ]
[ 2.2941 -1 0 ]
]

[ [ 2.8421 0 1 ] (added 1 to row)
[ 0 -3.2941 -2.2941 ] (subtracted 2.2941 from row)
]

[ [ 4.0810 0 1.4359 ] (multiplied row by 1.4359 from next row)
[ 0 1.4359 1 ] (divided row by -2.2941)
]

[ [ 1.2389 0 0.4359 ] (multiplied row by 0.4359/1.4359)
[ 0 1.4359 1 ]
]

[ [ 2.2389 1 1.4359 ] (added 1 to row)
[ 0 1.4359 1 ]
]

[ [ 1.5592 0.6964 1 ] (divided both rows by 1.4359)
[ 0 1 0.6964 ]
]

input = 1.5592, output = 1
So 2nd gear ratio is 1.5592.

[MyM8V8]

Hi Joe,

Here are pictures of the part discussed.

[MyM8V8]

These are photos of the above kit. Sold by PATC as the Raptor Drive kit. It is essentially the later hardened reluctor shaft and drum from the ISS equipped boxes, with a modified stator support shaft, which allows it to be fitted to the earlier non reluctor LS1 type 300mm boxes 98 to 05. The kit also includes an uprated overun piston and the aluminium drum has a hardened steel re-inforcement ring pressed over the inner flange as shown.

Unfortunately this drum is the weak link of these boxes structurally. We need a 300m version - Mr P ?!!!

ETA: You can see "special use only" stamped on the stator support shaft.

[MyM8V8]

As you requested Joe, some of the other nice shiny bits for the build:

Sonnax performance kit, Superior Industries Billet Servo kits, Alto Carbonite 2-4 band, Rollerised reverse drum, beast sunshell, PATC 300M output shaft, PML +4 qt Ally pan, Poly bush gearbox mount.

It's OK I sold the wife.

[MyM8V8]

More pics.

[joecar]

Thanks for the pics... this will be a nice strong box...:cheers:

[MyM8V8]

Thanks for the pics... this will be a nice strong box...:cheers:


Hey Joe,

Thanks for the Math, not my strong point so=awesome.

Which leads me to another Q. As 1st will now be higher (2.84 vs 3.05). I presently have 3.46 in the diff. I also have a set of 3.73's in my cupboard.

Do I put the 3.73's in to compensate (Although I am expecting more HP and Torque from the new motor whcih should drive the higher ratio ok).

ETA: Ute is 3300lbs.

:cheers:

[joecar]

Oh, the one thing I forgot to mention about the math is: use these better precision (more digits) values 2.8421 and 1.5592 instead of 2.84 and 1.56... I am not sure exactly, but the better precision will always help the TCM.

[joecar]

I would try first with the 3.46 gear and note what difference the PATC gearset makes...

Then when you go with the 3.73 gear you will note the difference the 3.73 gear makes...

Otherwise, you won't be able to attribute the individual differences.

My $0.01.

[joecar]

...
but I have been told the T42 tune has to be absolutely spot on for it all to go together.The MAF/VE tables (and other tables) have to be good so the correct engine torque is calculated (I'm not sure how the ECM communicates to the TCM)... this ensures that base pressure is up.

The shift pressures have to be up, the shift times have to be down, the shift torque reduction has to be tuned to balanced to protect the driveline.


Also been told that whatever you do with a 4L65, the computer is the limitation and it would be a good idea to look at installing the sonnax vacuum kit to take it out of the equation (you have to fool it into thinking it is doing the job though).
...The computer is actually pretty good, it electronically does the same job as the vacuum modulator kit... but see other comments above.

You may need to install a shift kit toincrease the mechanical/hydraulic line pressure... but at the same time you have to watch the maximum line pressure.

If you look at the hydraulic schematics, you will see that the TCM controls the PCS solenoid which regulates "Torque Signal" hydraulic fluid pressure... Torque Signal pressure assists the pressure regulator via the boost spring... i.e. Torque Signal pressure adds to the mechanically/hydraulically controlled line pressure...

But, please do get several opinions on this from as many sources as you can.

[MyM8V8]

OK Joe, so the box is finally built and installed. Got to say there was a lot to be desired of the parts and quite a bit of machining had to be done. We had heard through the grapevine that there was a problem with the early 6 pinion sets, so I hope we didn't get one of those. We couldn't use the rollerised reverse drum due to bearing location (or lack of)

I only had a quick run round the block and I have a P0722 code which it says is VSS sensor low voltage. Came straight back to the shop as it wasn't sounding too good. I'll have to check the VSS plug when I get it on the hoist.

BTW I assume your prior calculations were to include a 5 pinion rear planetary? I adjusted the ratios you calculated and flashed in the updated tune. No codes (apart from the above)

[MyM8V8]

Just realised that the box we built was not the original from the truck and I found out that the car version has a 17 tooth VSS and the Ute has a 40 tooth VSS, so this could be the problem. Apparently the rear planetary whether 4 or 5 pinion should not alter the ratios? If this is the case, when I've checked, I assume I can just change the sensor type around in the speedo calulator applet in the tune?

[ScarabEpic22]

Id try changing the value in the tune first to see if you can get around it, if it works then your speedo and shifting should be fine and Id leave it alone. If not, then you'll be tearing back into the trans and swapping a 40 tooth VSS in. Cant hurt to try a 30sec flash right vs $$$ tearing into it!

[MyM8V8]

Id try changing the value in the tune first to see if you can get around it, if it works then your speedo and shifting should be fine and Id leave it alone. If not, then you'll be tearing back into the trans and swapping a 40 tooth VSS in. Cant hurt to try a 30sec flash right vs $$$ tearing into it!

Cheers Buddy, I'll try that. Just pulled the sensor out of the tailshaft of the original box to check it against the new one, just need to get it up on the hoist for a quick look see.

I assume once i change the VSS value, all the ratios and shift points are all accounted for?

[ScarabEpic22]

Dont know for sure...Ive never done it myself but it looks like it can be done.

[Taz]

North American built 4L65/70 transmissions that came in Gen IV V8 trucks had a 40 tooth VSS reluctor, and if memory serves, a 17 tooth ISS reluctor.

For what it is worth …


Regards,
Taz

[ScarabEpic22]

Im 99.9% sure you're right Taz, everything Ive read on my 4L70E in my TBSS has a 40 tooth VSS and 17 tooth ISS.

[MyM8V8]

North American built 4L65/70 transmissions that came in Gen IV V8 trucks had a 40 tooth VSS reluctor, and if memory serves, a 17 tooth ISS reluctor.

For what it is worth …


Regards,
Taz

On the 4L65E there is no ISS that came on the 70's AFAIK.

I tried adjusting for a 17 in the tune, still no luck.

[Taz]

Sorry that didn't help ... component reference I suppose is globally dependent ... 4L65 transmissions that were OEM equipment in Gen IV North American built trucks with a 4.8 L engine have an ISS ...


Regards,
Taz

[MyM8V8]

Sorry that didn't help ... component reference I suppose is globally dependent ... 4L65 transmissions that were OEM equipment in Gen IV North American built trucks with a 4.8 L engine have an ISS ...


Regards,
Taz

Thanks for your help Taz. I just wondered if the ABS sensors on the back axle could have anything to do with this problem. I fitted a pair of G force 300m stubs and the reluctor teeth are further in, so the sensors are only half covering the teeth.
I'm getting no mph on my display, and I just got a PO700 up, which appears to be a non specific alarm.

[Taz]

Reread this entire thread to get up to speed … are you getting a vehicle speed (correct or incorrect) either to the gauge cluster, or when logging the VSS ?

The rear axle speed reluctors may cause ABS or traction control issues - but should not effect the vehicle speed read out (to gauges or scanner) if your vehicle uses the transmission mounted VSS for this purpose.

I take it your vehicle uses an E40 and T42 combination ? A brief, simple log recording RPM, ECT, VSS, and transmission gear may help to determine what is / is not happening.

Additionally, if you could list any / all DTCs it would be helpful.


Regards,
Taz

[MyM8V8]

Reread this entire thread to get up to speed … are you getting a vehicle speed (correct or incorrect) either to the gauge cluster, or when logging the VSS ?

The rear axle speed reluctors may cause ABS or traction control issues - but should not effect the vehicle speed read out (to gauges or scanner) if your vehicle uses the transmission mounted VSS for this purpose.

I take it your vehicle uses an E40 and T42 combination ? A brief, simple log recording RPM, ECT, VSS, and transmission gear may help to determine what is / is not happening.



Additionally, if you could list any / all DTCs it would be helpful.


Regards,
Taz

Yep. E40 T42. Speed guage reading 0 mph all the time. Had P0722 (VSS low voltage) yesterday and Cheque powertrain icon today (P0700). Does not change manually or in D properly. had a couple of intermittant shifts but I'm thinking that without correct VSS signal the T42 can't work out what the hell to tell the box what to do!

Please note I have a 4200 stall thats quite loose. I also have a vibration but that might be to do with the Energy system poly mount?

[Taz]

OK … 4L60/65/70 PT (part throttle) upshift / downshift is controlled by vehicle speed - with no VSS signal to the ECM / TCM the transmission won’t function. The loose torque convertor and poly mounts won’t effect the VSS - will effect how the shifts will feel from the drivers’ seat once you are up and running.

Check the continuity of the 2 wires from the VSS - to the ECM / TCM pins. They should be OK given that the previous transmission worked correctly - but this check will confirm their validity, or indicate potential damage from the transmission install (all too easy to pinch wires).

Next confirm the reluctor on the transmission output shaft is correctly aligned with the VSS sensor assembly. Also try to count the teeth on the reluctor - odds are it’s a 40 tooth.

If these things check out OK - then the VSS sensor assembly may be faulty.

Sorry, I don’t have the schematics for the E40 / T42 pinouts or wiring harness (don’t touch E40s - no offence) - so I’m not sure which ECM / TCM pins the VSS wires connect with - for the purpose of the continuity check.


Regards,
Taz

[MyM8V8]

Hey, thanks for that Taz. You've confirmed everything I suspected. By alignment I take it to mean the two metal strips in the sensor should be horizontal (i.e same plane) to the reluctor teeth although I'm pretty sure this is hard to get wrong. I'll check it all out and let you know.

Quick note for you Taz. Mine is an Australian built truck (or ute as they are called) so the trans (although built in America) would be spec'd for GM Holden. Don't know if they're any different but my 4L65E definitely does not have ISS - only the VSS.

[Taz]

Yes sir, that’s the idea. Some transmission shops install the 40 tooth reluctor by heating it up with a torch, and quickly sliding it onto the output shaft - it’s an interference fit just like some piston pins are in the connecting rod small end. Using this technique, the reluctor may not always end up being exactly oriented.

I’m not saying this is what your transmission shop did - just good practise to check the alignment.

On the ISS comment - there may well be some “misnaming” of the transmissions in current GM trucks. What one supplier / dealer call a 4L65, another may call a 4L70. In the end, they all function very similarly.


Regards,
Taz

[MyM8V8]

Yes sir, that’s the idea. Some transmission shops install the 40 tooth reluctor by heating it up with a torch, and quickly sliding it onto the output shaft - it’s an interference fit just like some piston pins are in the connecting rod small end. Using this technique, the reluctor may not always end up being exactly oriented.

I’m not saying this is what your transmission shop did - just good practise to check the alignment.

On the ISS comment - there may well be some “misnaming” of the transmissions in current GM trucks. What one supplier / dealer call a 4L65, another may call a 4L70. In the end, they all function very similarly.


Regards,
Taz

Fair comment my friend. I do know we have a 300m aftermarket output shaft and that sizing was apparently problem, but I'm sure the reluctor would have been put in the right place.

Regards Gareth

[MyM8V8]

Taz. You were correct on the reluctor wheel. Not installed far enough up the shaft and therefore missing the pickups. I'll have to drop this out tomorrow and fix it.

Can you confirm that all 4L60E series boxes that use VSS have a 40 cog reluctor. Efilive gives you two choices in the speedo applet, 40 or 17. I assume the 17 is only for ISS equipped boxes?? Cheers Gareth

[Taz]

If memory serves the 40 tooth VSS reluctor is common to automatic transmissions (like the 4L60/65/70) and the 17 tooth VSS reluctor is common to standard transmissions (like the T56). Not sure if this is a "rule" or merely a generality. Believe the ISS reluctor is a 17 tooth on any 4L65/70 that is so equipped.


Regards,
Taz

[MyM8V8]

Well, got the box apart and tapped the reluctor (40 teeth) into the correct position and all appears to be well. Shifts are really good and firm without any harsh banging. Joecars calculations for the new 1 & 2 ratios were spot on. Need to get to the track now to see if the new ratios do save a couple of tenths.

[Taz]

Glad to hear you got it working ... nicely done !


Regards,
Taz