Camaross8887

I bought a transmission off a guy on craigslist because my 3rd gear was starting to flare in my 2004 silverado with 175k miles. The guy said the transmission was work perfectly when he took it out and i bought it off him for $275 with 69k miles out of an 2002 silverado.

So I swap out the transmissions, fill in with fluid and start running it throught the gears.

NO REVERSE - acts like it is in nuetral. The truck doesn't even drop the rpms when reverse is selected. However all for gears operate fine, very light shift feel but they do operate. There is also a small whine when the engine is at low rpms, mainly in reverse.

I have been researching this for the last few days and have narrowed down my options and would like to see if anyone on here has any experience with this situation. I have rebuilt 2 th350 that have worked awesome and this will be the first time ill be digging into a 4l60e.


1- Im going to check the boost valve since this will be the easiest item to check while the trans is still in the truck. I didn't touch the valvebody on the swap so im not sure if this could even be the cause but cant hurt to try.

also while in the valve body im going to check the reverse apply circut.

What i truly think it is after my research is #2

2- Tefon Seals broken by the pump on the strator shaft. I know they need a special tool but have many tutorials on how to get around that without damaging the seals on installation. THis transmission sat for a year an dwas bone dry when i got. im thinking these seals could have dried out and crack after no use and being dry.


let me know if you have any tips, tricks or experience with this situation. I know its a silverado but the transmissions are the same except for the tailshaft length.

Thanks

fast89stang

iTrader: (2)

reverse input clutch snap ring came off. I just had one at work the other day with 4k miles on it. I put the snap ring back in, and it came out again in about 100 miles. i ended up replacing the drum, snap ring and seals on the piston.

MaroonMonsterLS1

I highly doubt it's your Teflon seals. They can sit for years and not crack. If you tear into it and find that is your problem I would bet one got cut or rolled somehow not dried out. If you do replace them you don't need the tool. Get a coffee maker, make coffee without any grinds. a.e. just get the water really hot but this way it's filtered. Drop the seals in the water and let them equalize temperature. After they are hot they will give you the necessary stretch to get over the shaft and seat properly. once in, put a plumber's clamp, like the one that is used for airbox, hose fittings, etc. etc. on cars and tighten the seal into place. let it sit overnight. this is called "sizing" the seals so they will fit properly and last forever. there aren't many things that can cause reverse to fail though so good luck.

Camaross8887

This would effect the reverse function of the transmission? Also all these parts are located in the Reverse input drum correct? not in the very back end of the transmission?

fast89stang

iTrader: (2)

Yes, its the first drum you pull out and that is the only gear it will affect. When the snap ring comes out tho, it will cause the piston to over extend and tear the outer seal. But its a real easy fix.

performabuilt

iTrader: (25)

I would say something has happened to either the reverse input drum piston or the low reverse piston, Though seems odd if it was a "working unit" even if it sat for a while. I would also check that the small plate at rear of valve body is tight. But it even possible the sunshell stripped it can happen out of the blue but this would be indicated also by no second only a 1-3 shift no 2nd or 4th or reverse.

Camaross8887

http://www.daccoinc.com/pdfs/catalog...L60E_4L65E.pdf

Looking at the diagram, the snap ring is 893 and if it comes out of its holder it breaks the 335 outer seal?

I appreciate the help

Can i buys these pieces locally and seperate or woul di need to purchase a master kit online with all the seals and gaskets?

Camaross8887

The guy said it was "working" i also haven't been able to get intouch with him since i gave him the cash.

Im going to take apart the transmission this weekend and look at what i have to work with since it seems there can be multiple issues.

Would the input drum piston or low reverse piston look damaged? how would i tell if it was no good.

performabuilt

iTrader: (25)

It should be pretty obvious but before you take anything else apart check the plate I mentioned at rear of trans just under shift solenoid's 3 8mm bolts.

fast89stang

iTrader: (2)

The one I had was snap ring 892. You will see the seal sticking out around the piston and may see parts of it in the drum.

mrvedit

I've helped several people here in the last year with no reverse.
In a case identical to yours (installed a supposedly good but long sitting trans), I suggested that he put the rear wheels up and run engine and trans for 30 minutes in drive. It was a long shot, but his reverse did come back; so it did appears the teflon seals had shrunk and the spinning trans expanded them again. Here is that thread:

https://ls1tech.com/forums/automatic...rse-4l60e.html

You are correct that a messed up boost valve would give you no reverse, but no one has ever reported that. The reverse feed through the valve body is minimal. Certainly a good idea to check that all the valve body and separator plate bolts are tight as Frank (PerformaBuilt) recommended; trivial to do when the pan is off.

I've bought several transmission off craiglist with "no reverse", bought used pumps from disassembled transmissions, and in all those cases the teflon rings were shot.
IIRC, everyone I have helped on this forum with no reverse also found bad teflon rings. When the teflon seals go bad, then often ruin the inside of the reverse drum.

The following thread is extremely long, but starts with "no reverse" and goes through a complete rebuild in which I assisted at every step. The teflon seals were indeed bad, but the reverse drum also ruined the stator shaft which then prompted the OP to buy a new pump, etc. Once you open the trans it can be a slippery slope down a path of many details and complexities. However the OP was finally successful.

https://ls1tech.com/forums/automatic...n-rebuild.html

I include links in that thread to other threads about necessary tools and recommended books. Also recommended rebuild kits and options.