Cant figure out how to diagnose whats up with my 4l60e. Please help

[Burdom13]

So this just started happening after the truck sat for 4 months when i built the front suspension. but basically itll start up and drive fine for a few miles then it slips out of gear and wont re-engage at all. ill turn truck off and can get it to go into first for like half a mile or until 25mph/1500rpms and itll slip out again and i have to turn it off to get moving again. basically had to do this yesterday to get home, took forever. i dont smell anything burning or have crazy grinding going on either, and no check engine lights. has 220k miles and i doubt the previous owner ever serviced the trans. i have a the trans fluid and filter kit, but at a loss of whats up. also started to notice these issues when i would shift into reverse and it felt rough/abnormal/slight noises. any help would be appreciated!!! i sure as hell dont want to get rid of this truck after all the damn work i just put into it. its gonna be one hell of an OBS when these issues get addressed!!!

 

[GoToGuy]

So... We don't know what you have.. Mack, Peterbilt, Ram, Edsel,
Make, model, year, engine.
If you haven't got the OE service manual, it will have info you need. Diagnostic troubleshooting starts with basics.

 

[Burdom13]

lmao sorry 97 k1500 5.7L z71

 

[Schurkey]

I'd start with trans filter, flush fluid, see what happens.

Neither expensive, nor difficult; and if you drop the pan and it's full of debris, you'd not need to go any farther--it's rebuild time.

 

[NickTransmissions]

So this just started happening after the truck sat for 4 months when i built the front suspension. but basically itll start up and drive fine for a few miles then it slips out of gear and wont re-engage at all. ill turn truck off and can get it to go into first for like half a mile or until 25mph/1500rpms and itll slip out again and i have to turn it off to get moving again. basically had to do this yesterday to get home, took forever. i dont smell anything burning or have crazy grinding going on either, and no check engine lights. has 220k miles and i doubt the previous owner ever serviced the trans. i have a the trans fluid and filter kit, but at a loss of whats up. also started to notice these issues when i would shift into reverse and it felt rough/abnormal/slight noises. any help would be appreciated!!! i sure as hell dont want to get rid of this truck after all the damn work i just put into it. its gonna be one hell of an OBS when these issues get addressed!!!

Sounds like forward clutch pack is going out or possibly either forward sprag or low roller clutch. Additionally low-reverse sounds like it's on its way out as well.

Do you have any consistent movement in D2 or D1 or are the symptoms the same?

At 220k, its lived a long life, much more so than most of those things. I'd yank it out and rebuild at this point but first drop the pan to see what's at the bottom as well as the condition of the fluid. Cut the filter open and see if it's clogged as a clogged filter can cause the same symptom pattern.

If you see a whole bunch of burnt clutch material or any metal parts, put the pan back on with a few bolts then pull it out for rebuild.

 

[Burdom13]

Sounds like forward clutch pack is going out or possibly either forward sprag or low roller clutch. Additionally low-reverse sounds like it's on its way out as well.

Do you have any consistent movement in D2 or D1 or are the symptoms the same?

At 220k, its lived a long life, much more so than most of those things. I'd yank it out and rebuild at this point but first drop the pan to see what's at the bottom as well as the condition of the fluid. Cut the filter open and see if it's clogged as a clogged filter can cause the same symptom pattern.

If you see a whole bunch of burnt clutch material or any metal parts, put the pan back on with a few bolts then pull it out for rebuild.

So I dropped the pan and changed the filter and new fluid. Actually shifts and drives fine now, BUT today I can hear what sounds like tin banging around only when it’s in 2nd gear. But it’s shifting fine and pulls like normal. I’m just wondering at this point if I should just swap it out for another 4l60e just to keep the damn thing driving, or do the 4L80e swap? This is my DD right now so im just trying to keep this cost friendly.

 

[NickTransmissions]

So I dropped the pan and changed the filter and new fluid. Actually shifts and drives fine now, BUT today I can hear what sounds like tin banging around only when it’s in 2nd gear. But it’s shifting fine and pulls like normal. I’m just wondering at this point if I should just swap it out for another 4l60e just to keep the damn thing driving, or do the 4L80e swap? This is my DD right now so im just trying to keep this cost friendly.

What did the old fluid look and smell like?
What was at the bottom of the pan, if anything?

 

[Burdom13]

Sorry I never update my threads. Had a lot of shavings clogging filter and after new fluid and filter ran for about a week and I blew up the trans today. Fun stuff!!

 

[Burdom13]

Got lots of droop travel for stock leafs eh?

 

[Medic0893]

So I dropped the pan and changed the filter and new fluid. Actually shifts and drives fine now, BUT today I can hear what sounds like tin banging around only when it’s in 2nd gear. But it’s shifting fine and pulls like normal. I’m just wondering at this point if I should just swap it out for another 4l60e just to keep the damn thing driving, or do the 4L80e swap? This is my DD right now so im just trying to keep this cost friendly.

Turn the radio up...