4l60E 4th shift pressure 96PSI

[bmc1025]

Here is the stock TCM file for my 07 TahoeAttachment 17808

Keep in mind this is a 6000LB SUV with a 4l60E and a 5.3 .

Take a look at (D8301) 3>4 Shift Pressure it is all 90 and the (D3104) 3>4 Torque reduction is 0. (D3101) 3>4 Shift Time is 0.0. Don't pay any attention to the other shift times, as this is a soccer Mom SUV.

The Base Pressure for the 3>2 downshift (D8203) is set at 90 across the board also.

[joecar]

Here is the stock TCM file for my 07 TahoeAttachment 17808

Keep in mind this is a 6000LB SUV with a 4l60E and a 5.3 .

Take a look at (D8301) 3>4 Shift Pressure it is all 90 and the (D3104) 3>4 Torque reduction is 0. (D3101) 3>4 Shift Time is 0.0. Don't pay any attention to the other shift times, as this is a soccer Mom SUV.

The Base Pressure for the 3>2 downshift (D8203) is set at 90 across the board also.

How does the 3->4 shift feel at low/mid throttle...?

The stock truck 4L60E did not have the larger area 2nd servo, so that's one way to provide sufficient clamping.

[bmc1025]

Believe it or not it is not harsh at all. It must be restricted in the VB. The 3>2 shift is harder, but I would describe it only as almost firm.

I would assume this is actually a 4L65E or 4L70E but I have not had one of these exact transmissions apart. I also think you are correct about the 2nd servo piston. My wife's s-10 has the larger servo and 2nd is much more firm, shifting up and down. I have to use a little TR to soften the shift at lower throttle.

[Brad Kimbler]

Believe it or not it is not harsh at all. It must be restricted in the VB. The 3>2 shift is harder, but I would describe it only as almost firm.

I would assume this is actually a 4L65E or 4L70E but I have not had one of these exact transmissions apart. I also think you are correct about the 2nd servo piston. My wife's s-10 has the larger servo and 2nd is much more firm, shifting up and down. I have to use a little TR to soften the shift at lower throttle.

Its hard to get a firm or hard 3-4 shift, I usually build 3-5 4l60es a month for 10-11 sec cars as well as stock builds..I totally block off the 3-4 accumulator and DOUBLE the valvebody feed, this makes it noticeable, but still not hard to bad whatsoever. As far as the tune...Turn it up in my opinion...If I'm doing a stock truck with stock trans tune, I will usually highlight the entire 4th gear shift table and add 10-20 at least, even on my built transmission, its not a hard shift...Just make sure you DO NOT have the converter locked during a shift..most OS prevent this from happening but I have seen it able to lock during a 3-4 shift and that's very damaging to the trans, most of the time your better off eliminating 3rd gear lockup anyway. As far as billet servos...eh...I favor the corvette second gear servo and stock 4th gear servo . The stock 4th gear servo is plenty IF the mods are done during as build as I mentioned, or if you go into the tune and add to that 3-4 shift table. Oh and as far as maxing the shift table out, I wouldn't do that, just add to it, if the pump sees too much pressure to often the pump rotor has been known to crack preventing any movement. Now if you pull the trans andf add a billet pump rotor...go for it..

[bmc1025]

Oh and as far as maxing the shift table out, I wouldn't do that, just add to it, if the pump sees too much pressure to often the pump rotor has been known to crack preventing any movement. Now if you pull the trans andf add a billet pump rotor...go for it..

It is already maxed out from the factory in the Tahoe.

[HellKnightHicks]

1-2 is easy to get a firm crisp shift.... 2-3 is harder to accomplish. 3-4 you can make noticable but not crisp.

I think the size and weight of the vehicle is a contributing factor as well.

1-2 will slam even with Tq Management and the stock pressure tables.

2-3 i start at somewhere arround 25 PSI and work up to max 96 by arround 275flbs

3-4 is maxed at 96 PSI all the way across

Its hard to get a firm or hard 3-4 shift, I usually build 3-5 4l60es a month for 10-11 sec cars as well as stock builds..I totally block off the 3-4 accumulator and DOUBLE the valvebody feed, this makes it noticeable, but still not hard to bad whatsoever. As far as the tune...Turn it up in my opinion...If I'm doing a stock truck with stock trans tune, I will usually highlight the entire 4th gear shift table and add 10-20 at least, even on my built transmission, its not a hard shift...Just make sure you DO NOT have the converter locked during a shift..most OS prevent this from happening but I have seen it able to lock during a 3-4 shift and that's very damaging to the trans, most of the time your better off eliminating 3rd gear lockup anyway. As far as billet servos...eh...I favor the corvette second gear servo and stock 4th gear servo . The stock 4th gear servo is plenty IF the mods are done during as build as I mentioned, or if you go into the tune and add to that 3-4 shift table. Oh and as far as maxing the shift table out, I wouldn't do that, just add to it, if the pump sees too much pressure to often the pump rotor has been known to crack preventing any movement. Now if you pull the trans andf add a billet pump rotor...go for it..

What about 13 vane rotor? Im not running the stock 10 vane.

[Brad Kimbler]

1-2 is easy to get a firm crisp shift.... 2-3 is harder to accomplish. 3-4 you can make noticable but not crisp.

I think the size and weight of the vehicle is a contributing factor as well.

1-2 will slam even with Tq Management and the stock pressure tables.

2-3 i start at somewhere arround 25 PSI and work up to max 96 by arround 275flbs

3-4 is maxed at 96 PSI all the way across



What about 13 vane rotor? Im not running the stock 10 vane.

13 vanes are worse about breaking, the extra vanes are slots in the same diameter rotor as a 10 vanes, so 3 more slots thin out areas on the rotor...The main stress point is converter installed depth not being deep enough into the rotor, also running a extra quart low or over filled as welll can cause pressure spikes, damaging the rotor...this is not a super common failure..over the past few years I have seen 4 broken stock rotors, one of those being my build, this is why i only do performance builds with billet rotors now.. I'm not trying to make anyone paranoid, just trying to help give 60es a good name ...

[HellKnightHicks]

Circle D torq converters come with a kit to make sure that you properly shim the TC into the tranny.

Most everybody seems to hate 4l60e's I got 222000 out of mine in my white truck... In my blue one i got around 200,000 before it blew... Not a bad tranny... Coolers really seem to help them stay alive... even those little dinky stock coolers make one heck of a difference.

But you gotta either build it yourself or find someone who is good with trannys... Preferably local.

[HellKnightHicks]

Here is the stock TCM file for my 07 TahoeAttachment 17808

Keep in mind this is a 6000LB SUV with a 4l60E and a 5.3 .

Take a look at (D8301) 3>4 Shift Pressure it is all 90 and the (D3104) 3>4 Torque reduction is 0. (D3101) 3>4 Shift Time is 0.0. Don't pay any attention to the other shift times, as this is a soccer Mom SUV.

The Base Pressure for the 3>2 downshift (D8203) is set at 90 across the board also.

Would be nice to be able to control the down shift pressure but the Express Van OS doesnt have a table for that... The only thing thats close would be the temp adjust.
Wonder if it cold be indirectly controlled from thoes temp adjust tables.

[bmc1025]

If I had some free time I would hook up my gauge and test it out. It will be a while before that happens though. Is any of your down shifts too soft?