Will a 6 pinion planet gear work in 4L65E

[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