4l60 – 4l60e

[Sejo]

I’m pushing a 1999 Chevy Tahoe with the 4L60E. The tranny recently went out on me and these were the symptoms; No Reverse/2nd or 4th Gear. Turns out it there is a TSB out on this (Bulletin No.: 00-07-30-022C) and it explains that it is the Reaction Sun Shell (Replace Reaction Sun Shell with More Robust Heat Treated Parts).

So I had it towed to a shop the next day (in a hurry without thinking) because I needed it running again ASAP…it is my daily. Turns out I should have done my homework first and I should have gotten this: http://www.transmissioncenter.net/4l60e.htm

Anyways, the truck was towed I was already out $500 for the “check up†so I went ahead and let the shop do the work. $2500 later (INSANE) I had my truck back. I showed them the above link and I talked them into “using†heavy duty parts and bigger servos; in a sense building up a “heavy duty†transmission; who knows what they put in there.

So far it has been running “decentâ€, but I cannot get over the hard shift between 1st & 2nd. I took back once for this because the shift was insanely firm/harsh/hard and they said they had to adjust the line pressures. When I got it back it was “better†so I took off with it, but now it is bothering me again – still hits to hard from 1st to 2nd gear.

Now for my question…..

Does one need to drop the transmission pan to adjust the line pressure or is all that done via program through the ECU? I am convinced that with these bigger servos in the tranny, they are not quite sure how to adjust the line pressures.

 

[96ProCompTahoe]

wow you got SCREWED. i've having mine rebuilt with the extreme duty torque package, new GM 5 gear planetaries, and upgraded everything else possible.

Not sure on the line pressure, but i asked if i could have mine tuned to shift harder and was warned it would be easy to blow the rear end out of the truck. if its shifting really hard, keep your foot out of it...

 

[bparker]

Yep, they need to drop the pan to access the valves. :yesnod:

 

[Sejo]

Here's what they've listed as having replaced:

HD Torque Converter
8642079 HD Piston, 2nd Servo
24200437 Plate, Valve Body Se
8647084 Spra, Forward Clutch
New Sun Gear Shell

I don't know what brand parts they put in.

 

[Sejo]

Yep, they need to drop the pan to access the valves. :yesnod:

What does it take to swap out a servo?

How about the valve body?

Do they have to pull the Transmission or can they just drop the pan? I think I am about to call them and ask them to swap that stuff out for me back to stock if they can't adjust it correctly.

The guy at the shops was trying to tell me that the 1-2 shift bang was because of the HD Torque Converter......

 

[95TwinTT]

There is no doubt that the various parts changed in your trans, caused the higher pressure at the 1-2 shift point.

The good news is, it is totally controlled by the ECU. They need to make some adjustments in the "Force Motor" tables. I don't know which ECU you have, but someone near you must have ability to edit those changes.

The 4l60e totally controls the trans pressure with solenoids. Each gear has it's own table.

 

[GMCYukalade]

And, if you have a superchips programmer, you can do this yourself... just a heads up - its about $350 bux

 

[Stillakilla187]

hey 96procomp how much you pay for all of that, and installation and everything

 

[96ProCompTahoe]

the trans or everything.