4l60e rebuild with success/problems

[95sierra]

Hello everybody! Ok about 6 months ago I acquired a 95 swb Sierra with the 5.0,when I first got it I didn't really notice the horrible 1-2 shift until after it was warmed up and it was really bad when u were giving it 1/2 or less throttle anything above that and I'll tell ya it's like a switch is being pressed (literally) and it shifts like butter every time........
To get around this I usually took off in 2nd if the slippage wouldn't be too bad (hills,etc,etc) or just give it good throttle to make it shift smooth.Well in 2nd one day I was pulling out of the drive and it sounded like I ran a can over and that was it the pump went.
I replaced:
Sun shell-beast
New clutches/seals/Pistons
Superior shift kit
Bushings
New trans go separator plate
Pump

Now to the problem after the rebuild it was perfect the 1-2 shift went off w/o a hitch bump boom or bang and it did I this consistently and the one day about 250mi into the rebuild I take off and dang 1-2 banged like no tomorrow so now I need help diagnosing this everything was 100% and out of no-where she's at it again my thought is high line pressure but I just need help diagnosing.Thanks!

 

[SkyHighColorado]

did you replace the solenoids in the pan? Mine started to bang 1-2 in rush hour traffic and it solved my problem. I got the solenoid it on ebay for $170 I think. you could just replace 1-2 sift solenoid but its so easy to do the others.

 

[95sierra]

The solenoids weren't replaced but tested good.Today I put in a vette servo and mid-upper range I can tell its clamping better but just a regular 1/8-1/4 throttle shift still feels so wrong,my truck is a 95 and most people say I can jump a and b slots on the plug under the dash and I did but I can't get it to work the check engine light isn't even on not has it been on.The truck seems to make its 1st shift smooth and this is hot or cold pull up to grocery store run in n out and it takes off the first time shifting smooth but the first light its back at it im tired of dreading stop lights/signs

 

[beardeddummy]

May even be a torque converter clutch solenoid. My 97 did that and that was the problem. Check the wiring for breaks to

 

[95sierra]

Yea I was kinda thinking either that or the epc I guess I need to start by getting her scanned please continue any suggestions and I will continue updating what I've tried hopefully I can get her worked out before she breaks again.

 

[95sierra]

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Well the dam vette servo didn't work has anyone even seen the dam tranny housing crack like this?That pressure had to have been HIGH lol.I took off today and thought dam she's shifting good then later on 4th gear wasn't kicking in and I thought the servo was leaking then looked and realized I was lucky to make it home.The servo pin was the original I could see if it were a long pin or something but nope.

 

[VCaddy]

Looks like you didn't get the servo snap ring in correctly. You'll crack the housing in a hurry if that snap ring isn't seated right.

http://www.gmt400.com/forum/showthread.php?50-4l60e-vette-servo-install

 

[95sierra]

Yea after not much googling I realized that yes this was my mistake so that one was hard to take but ohhh well stuff happens.---Now on to my temporary fix and odd results,at least 75%of the ring groove was fine so I just roughed up the whole thing and just jb welded the whole servo in place not u till after it was hard as a rock I realized the 4th apply o ring must have been cut or something during the failure and I have no 4th gear sucks right? Not really and here's why 1.I don't really have a choice unless I wanna risk messing it up worse 2.I only drive back and forth to work and no where in town is 55+ even a speed limit 3.This is the one I'm stumped on,every since I welded the servo in my 1-2 shift has been PERFECT and to me it's a crazy trade but one that I'm going to live with until I feel like rebuilding the other trans I have laying around.Can anybody think of why the 1-2 shift smoothed out with 4th gear gone? Maybe tcc valve doesn't have a chance to slip and up line pressure?