Tranny Slipping

[MizZ71]

I recently replaced my rear main seal and surprisingly went fairly well without a lift. So tranny was partially removed from the truck. Got everything buttoned up, drove several times and thought all was good. Recently I started noticing a little slip at takeoff. It seems pretty consistent, when I'm at a stop and hit the gas it slips for like a second, then drives pretty normal from there. The tranny has about 225k miles on it. Fluid is good and I don't have any extra screws from the rear main project :). I'm going to inspect and make sure the bolts from flexplate to torque converter are tight. I have regular tranny fluid in the transfer case right now, not the auto trak II that is recommended. Any help to guide me down the rabbit hole is appreciated. Thanks, Nick.

[Supreme Pizza]

It sounds like you probably need a new transmission. When is the last time the transmission fluid was replaced? Did you drain it or anything on the rear main repair?

[richard wysong]

yeah doesn't sound good, as a last resort try over filling it and see if it helps. you can try dropping the pan and changing the fluid and filter but you may find that it wont do anything after if the pumps failing and it looses its prime. 

[richard wysong]

you may be better off to have it flushed, its been known to cure all kinds of problems. how does the fluid look? burnt or metalic looking?

[Supreme Pizza]

If its slipping, you don't have much to lose. You could try adding some ATP-205, to condition the seals. You could try replacing the filter. You could try dancing around the truck with a candle in each hand, chanting "No-slippy slippy, No-slippy slippy". Either way you slice it, your probably looking at a new trans.

[Supreme Pizza]

I remember checking someones transmission fluid once, and the dipstick looked like it was dipped in silver glitter nail polish. They said they thought it was slipping. It made it about 20 miles, then it went to the scrap yard. From my experience, if the transmission is slipping - check the fluid level. If the fluid level is full, then your screwed. Get AAA, and drive it till it dies. Start looking for a trans, or another rig. The only thing you can do to prolong its life is to prevent slipping as much as possible. Take it easy on the acceleration, start off slowly, avoid high gear.

[swathdiver]

2 hours ago, MizZ71 said:

Recently I started noticing a little slip at takeoff.

 

...I have regular tranny fluid in the transfer case right now, not the auto trak II that is recommended. 

Nick, start with putting the correct fluid in your transfer case before firing the parts cannon at your truck.

[Supreme Pizza]

4 minutes ago, swathdiver said:

Nick, start with putting the correct fluid in your transfer case before firing the parts cannon at your truck.

 

 

Ya, the correct fluid would be a fine place to start.

[MizZ71]

13 hours ago, Supreme Pizza said:

It sounds like you probably need a new transmission. When is the last time the transmission fluid was replaced? Did you drain it or anything on the rear main repair?

Fluid/filter/o-ring was done back in 2017-18ish. Well lets just say during the rear main many a fluid was spilled. I had to add back in a quart or two, but no flush.

 

Obviously a big concern was should I just get a new tranny while doing the rear main, but the tranny has done me well over the years.

Edited December 19, 2021 by MizZ71

[MizZ71]

12 hours ago, richard wysong said:

yeah doesn't sound good, as a last resort try over filling it and see if it helps. you can try dropping the pan and changing the fluid and filter but you may find that it wont do anything after if the pumps failing and it looses its prime. 

Ok yeah I inadvertently overfilled a little last night and will test today, then change fluid/filter and pray, thanks. 

[MizZ71]

12 hours ago, richard wysong said:

you may be better off to have it flushed, its been known to cure all kinds of problems. how does the fluid look? burnt or metalic looking?

Ok will do and fluid looks pretty good but I'll take a closer look when I flush. Thanks.

[MizZ71]

12 hours ago, Supreme Pizza said:

If its slipping, you don't have much to lose. You could try adding some ATP-205, to condition the seals. You could try replacing the filter. You could try dancing around the truck with a candle in each hand, chanting "No-slippy slippy, No-slippy slippy". Either way you slice it, your probably looking at a new trans.

Cant forget to dance!

[MizZ71]

12 hours ago, swathdiver said:

Nick, start with putting the correct fluid in your transfer case before firing the parts cannon at your truck.

Right, will do. Keep the firearm holstered.

[richard wysong]

the transfer case fluid doesn't matter, trans fluid will work just fine. the transfer case is purely a mechanical connection and can't slip

[dna9656]

My tranny guy says never run anything but the AC Delco tranny fluid, even though the law says they are all compatible (that changed YEARS ago) he thinks there's something in the AC Delco that's proprietary, he's DA man, I do what he says, he rebuild my 4l60E to a 4l70E and I've had no problemos.