4l60 - 4l60e

[jrbueiz]

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 “decent”, 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.

[MT-2500]

Sounds like they shift kited the valve body to much.

I would have them put a stock valve body back it it and be done with the hard/bang shift stuff.

No adjustment on line pressure.
Did they reprogram or mess with the transnmission computer?

[2000CAYukon]

About 4 years ago, I called that website that you listed to get some help on a weak 1-2 shift on my 90 GMC K1500 700R4 (4L60). There advice was billet servos (both intermediate and 4th apply) and no shift kit. I have learned a lot since then and I can tell you that for me, it was a waste of money for the billet servos. It had a nasty 1-2 shift and would usually chirp the tires if really steped on it. The problem was at light throttle, the 1-2 shift was harsh. Eventually, I installed the Transgo Jr kit and a corvette servo with the original 4th apply servo. My original issue was the TV valve and worn servo seals. I should have researched it more and I was a little foolish to listen the them.

The billet servo (intermediate) requires some valve body mods to work right and I do not recommend it. The vette servo along with a transgo kit would have been the way to go along with a beast sun shell.

IMHO, this is a much better setup then transmission center recommends. I learned the hard way.

This link is for 93-97; however, this is the setup I would have gone with for your 99: https://www.700r4l60e.com/store/prod...&cat=18&page=1

//2000CAYukon

[jrbueiz]

Originally Posted by 2000CAYukon

About 4 years ago........

Thanks for the info.

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.

[2000CAYukon]

Originally Posted by jrbueiz

Thanks for the info.

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.

The part numbers you listed seem to be AC Delco part numbers; although, I am not sure the Servo is a Corvette servo or not.

It would be good to know if they installed a shift kit or not and if they modified the spacer plate for the Corvette servo.

I have no issues with the Corvette servo installed in my 90 K1500.

//2000CAYukon

[jrbueiz]

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......

[MT-2500]

Originally Posted by jrbueiz

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......

I can not see the converter giving a hard shift.
The problem is in valve body and may be some servo.
The valve body can be changed with a pan drop.
2-4 servo is on the side of transmission.
Can be changed without droping transmission.

On the valve body and or spacer plate is is hard to tell what they have changed in valve body.

I would have them get a stock rebuilt valve body that has the hard updated shift/tcc valves. And rest oem stock.

Also when pan is off check foor jave them show you any metal or trash in the filter and bottom of the pan.
Good luck
MT

[MT-2500]

[quote=MT-2500]I can not see the converter giving a hard shift.
The problem is in valve body and may be some servo.
The valve body can be changed with a pan drop.
2-4 servo is on the side of transmission.
Can be changed without droping transmission.

On the valve body and or spacer plate is is hard to tell what they have changed in valve body.

I would have them get a stock rebuilt valve body or a good used one out of the SAME YEAR AND MAKE OF TRANSMISSION..
2002 should all have the hard updated TCC and shift valves OEM.

Also when pan is off check foor jave them show you any metal or trash in the filter and bottom of the pan.
Good luck
MT