calling tranny experts, need help asap! 4L65E down :(

[02gmcbandit]

well i posted over on PT about this , still havent found the issue, even bought a ATSG book that came in today which seems to be a waste of money, it has some good info about the parts but i'm needing a book that shows step by step how everything is assembled because i think theres two parts that the snap rings came off because when i took the tranny apart the snap rings were popped off. anyways heres the story of what happened


was driving to waycross to help my buddy with a motor swap. stopped on a side road to take a piss, went to get back onto the highway under about part throttle maybe, got to around 20-25 and it went to shift into 2nd and i heard a loud bang and then the rpms started going up but i wasnt gaining speed at all.eased out and slowly mashed the gas and it started going, let it get to about 55 and was wondering what was going on so floored it, rpms pegged and i was going no where again like it was slipping. pulled over to check, nothing was leaking, fluid was fine. so i went to get back in and put it in drive and it wouldnt go anywhere, rpms would just pegg, pulled it to 3rd, same thing, pulled it to 2nd it slowly started pulling off but still could tell something was wrong, pulled it to 1st and it was fine. had to manually shift it through town because everytime i let it drop below 30ish in drive it would pegg rpms and go no where. well if i start in 1st i can floor it, easy out and shift into 2nd, floor it in 2nd, same with 3rd. i can hold it to the floor in each gear and it not slipp once, just when it goes to change gears it wanted to and when having it in drive. the gear band is fine no wear so i know that wasnt slipping, clutches are fine no wear there either.

i figured something broke in the tranny but i have the tranny apart and cant seem to find anything broken, could it be my converter???


i need to figure out whats going on soon, its been down two months and i dont even know whats wrong with it, like i said i also need a link or some info on what book to actually buy because the one i bought doesnt even have pics of the tranny going together, its the revised edition for 4L60R/4L65E.

my truck is a 2002 gmc sierra 5.3 with 4L65E

any help is greatly greatly appreciated

[chevrolet all the way]

you said it had snap rings popped off when you took it apart??? which ones?

you built this yourself?

[casey23]

Sounds like broken Sunshell....... no reverse?? No OD... broken or splines stripped...

[02gmcbandit]

the snap ring that holds this down was popped off



and this snap ring or w.e. was just sitting on this part freely, didnt see where it went though. thats why i bought at atsg book so see where everything goes but guess i bought the wrong book




yes i built this tranny myself about 2 years ago at the tech college i was attending. since being built it has made numerous passes down the track, numerous street passes, has about 20k miles on it . didnt have any issues and wasnt even under wot when this happened, like i said maybe part throttle.

and yes it still had reverse and OD, just like i said if going 30ish or slower in OD it wouldnt do anything , i'd have to downshift to 2nd. but once i go past 30ish-40ish while manually shifting i could put it in OD. and even in OD if i gave it gas to pickup speed it would, just as long as i didnt give enough to make it downshift, if i did it would peg the rpms

[GasGuzzler]

There is more than one issue. No one thing makes all that happen. Those are the forwards in the "drum" pic. Not much in there other than one piston and the forwards. Some of the story sounds like sprag, some like 3-4, some like sunshell.

[RedHeartbeat]

Nice carnage. I'd have to get my hands on that one to diagnose it. I'd replace the reverse drum with a new/reman unit. Some places on Ebay sell a whole assembly ready to go with new piston and clutches already installed. That one's a tricky buggar to put together without the right tools. The other snap ring is supposed to be in the groove on that gear and it bottoms out against the sunshell IIRC. Replace the sunshell with a beast sunshell while it's apart, the stocker is notorious for failures. Replace the gear if the edges where the snap ring goes aren't good and sharp. The snap rings definitely gotta be replaced. I get all my parts through Transtar, good company for quality parts at a decent price. Oh yeah, that gear going to the sunshell comes out of a planetary set that likes to break from time to time under nitrous. If it's the four gear planetary try to get a five gear planetary out of a true 4L65e. There are lots of cheapie copies so be sure you ask for OEM parts.

[GasGuzzler]

....and STOCK sunshells haven't been a problem in STOCK transmissions with STOCK engines since about 2003.

[02gmcbandit]

i have no idea what you're refering to, i'm slower than a bus remember , hmm well i'm going to inspect everything in the morning and see if theres any wear on any splines or anything. never hurts to double check things, i'll also check out Transtar , thanks for the info.

[ls1ram]

In the first pic thats the reverse clutches, and that clip popped off on me before during a teardown. But really that clip being off shouldn't cause any major problems. they normally pop off when line pressure is to high or rpms are to high when engaging into reverse. most gm motors rev to 1,000K during a cold start up and most people( I catch myself doing it) will just put it in Reverse before the engine idles down.

Now the second pic is a rear sun gear. The clip is out of place in the picture. look at the pic again and see those straight splines??? and the grove thats cut in the bottom half? thats where that clip goes...That clip will hold the sunshell in place. Its possible this is what happened the sun gear(from the clip not being in place) let the sun gear walk out of the sun shell splines.....

Get a new rear sun gear clip and get the wide bushing to keep it more stable. also on the reverse drum clip, its best to get a new drum and try and change your driving habbits alittle on the cold start ups.

[ls1ram]

Here is a pic of the rear sun gear with the clip in the right position and with the sonnax extra wide bushing for support