Hey all,

looking for some help with my transmission. Recently rebuilt a 4L60E for my truck. Reinstalled and everything worked. I figured since everything mechanically was new, I would install a TransGo shift kit, corvette servo, and some pinless accumulator pistons to tighten up the shifts and prevent any line pressure issues from a worn valve body.

after installing the shift kit, I have reverse, 1st gear, 2nd, 3rd, all shifting perfectly if I shift MANUALLY from the column. When the truck is in drive, I have slipping occurring in 1st, 2nd, and 3rd. At highway speeds, I can shift into drive and 4th gear also functions without slipping.

Trying to get some advice on what may be causing this issue after rebuilding the valve body. I’m planning on taking it back apart tomorrow and verifying that I did everything per the instructions and install a new separator plate.

 

Thats a hard one. My first thought would be an issue with the sprag. But you said worked fine before. The only thing that changes in the D4 is absence of the overun clutch use in 1st and d3 which would point to issue with the FWD clutch. But I am unsure what you could mess up in the shift kit to cause an issue with the FWD clutch.

 

just took everything apart and found an unplugged connector. (It was long day yesterday)

put everything back together to find the same issue. I saw some posts about the pinless pistons and incompatibility with the transgo shift kit, so I might start by throwing the old pinned pistons back in and see if there is any change.

 

Pinless pistons? How did you block the pin hole in the FWD accum? If the ball they actually can fall out handling the VB. that would make the leak for fwd and explain all. it would not be in pan but rather laying behind the accum piston in bore. I would pull pan and look at that first as it does not require VB removal. This issue is why I actually cut a small piece of the original pin to block the hole instead.
Contrary to belief they is not inherent problem with using the pinless with the TG kit as long as you stay with the OE spring and layout for the accum.
Like I said CHECK THAT FIRST !

 

Which shift kit are you using specifically?

I have the SK-4L60E in mine, I used pinless accumulators, and you put the ball in but stake it in place to plug the hole.

 

The pinless pistons will work with the TransGo kit as Frank says. With the exception of the 1-2 accumulator. When using a pinless piston in this position you cannot place a spring on both sides of the piston as the TransGo instructions say to do. The Sonnax piston is taller and when installing a spring on both sides of the piston there is no room for the piston to move. If using the pinless piston with a TransGo kit just install one spring as per the Sonnax instructions.

 

Yes, Mr Bond has that absolutely correct. I used the Sonnax supplied spring; however found the 1->2 shift too soft and therefore went back to the OEM piston with the HD2 springs and used one washer under the spring.

 

The 1-2 feed hole in the separator plate will also make a difference on the 1-2 shift feel. I used one Sonnax purple spring part # 74926 with the pinless piston along with a .099"inch 1-2 feed hole in the separator plate.

 

I find all the different variations interesting. Not wrong mind you, Just interesting haw each gets where they are headed.
In my case I do not use the TG kit and generally with pinless or stock style metal accums use the stock springs and layout. Depending on application for feed sizes . If HD build the .083 VB accum gets stiffer spring, Moderate performance larger .092 feed with VB accum spring stock. More aggressive performance back to .083 and stock with added VB ACCUM spring (pretty stiff set up) , With very high stall and big power duals springs in VB ACCUM and .092 feed. Accum feed (to back of servo I leave stock.These all when I use wide band and corvette servo Stage 2 and HD build.
Now with the stage 3 and max which use the superior pancake servo. I use stock VB accum spring- .083 second feed and .092 3rd acum feed stage 3 and with the MAX . 093 feed with dual spring VB accum and .092 3rd accum feed.
Needless to say the stage MAX is pretty aggressive shifting . But people do not get those for comfort. and they are used for most extreme duty.
I have never been a fan of overly aggressive shifts In any regular day by day use type unit as I feel it places more than necessary strain on hard parts . In particular the input drum (To me still the weakest mechanical link in the 60E series trans) My goal is alwayS in particular for second is a notable firm little bump at part throttle becoming more aggressive with throttle but never slamming tire squawking even at WOT.
I also may adapt feeds to various situations. Bigger stalls may get bigger feeds, Lower rations like 4.11 4.56 may get smaller holes while high gears like 3.08 in my own car get .092 .
Never cared for modding the 1-2 accum as I find that when this is done I get less than consistent feel at varying throttle levels.
Just my thoughts.