TH350 Slips in Drive but will back up

[TravisB]

My grandfather's 84 k10 has sat for ~5 years on the side of a hill in the yard with a bad fuel pump. He had a newer truck that was easier to drive than to fix the old truck and we never really needed it until recently. My Duramax was giving me all sorts of trouble and needing a truck I decided to put a fuel pump on this and keep working.

I got the truck going but the pan was completely dry. It had a leak to begin with and where it was on a hill it leaked it totally dry. I expected this and put 4 quarts in it before starting it up. After starting it I backed it down onto a level place and made sure it was full of fluid and tried to move the truck around a bit but it would not go forward. Seemed to have no issues backing up but it did take a while to engage after you select a gear on the column. I could feel it engage drive but it wouldn't grip enough to move around.

Is the trans due a total rebuild? It was fine before the fuel pump quit, is there something that could be done to save it without pulling it?

 

[Vbb199]

My grandfather's 84 k10 has sat for ~5 years on the side of a hill in the yard with a bad fuel pump. He had a newer truck that was easier to drive than to fix the old truck and we never really needed it until recently. My Duramax was giving me all sorts of trouble and needing a truck I decided to put a fuel pump on this and keep working.

I got the truck going but the pan was completely dry. It had a leak to begin with and where it was on a hill it leaked it totally dry. I expected this and put 4 quarts in it before starting it up. After starting it I backed it down onto a level place and made sure it was full of fluid and tried to move the truck around a bit but it would not go forward. Seemed to have no issues backing up but it did take a while to engage after you select a gear on the column. I could feel it engage drive but it wouldn't grip enough to move around.

Is the trans due a total rebuild? It was fine before the fuel pump quit, is there something that could be done to save it without pulling it?

I'd change the trans fluid filter, it might be packed up with ****, just a thought. Thats the easiest place to start

Any whining from the fluid pump?

It sounds like its just low on fluid, you sure the level is correct?

 

[Vbb199]

I suppose if all of that checks out, you could flush it of all its fluid, might be some crap in there causing it to not engage.

 

[C10MixMaster]

My grandfather's 84 k10 has sat for ~5 years on the side of a hill in the yard with a bad fuel pump. He had a newer truck that was easier to drive than to fix the old truck and we never really needed it until recently. My Duramax was giving me all sorts of trouble and needing a truck I decided to put a fuel pump on this and keep working.

I got the truck going but the pan was completely dry. It had a leak to begin with and where it was on a hill it leaked it totally dry. I expected this and put 4 quarts in it before starting it up. After starting it I backed it down onto a level place and made sure it was full of fluid and tried to move the truck around a bit but it would not go forward. Seemed to have no issues backing up but it did take a while to engage after you select a gear on the column. I could feel it engage drive but it wouldn't grip enough to move around.

Is the trans due a total rebuild? It was fine before the fuel pump quit, is there something that could be done to save it without pulling it?

Yes you need a rebuild the seal died sitting for that long. however you can try this, we have bought a couple extra years on a 4l60e with a reverse that was chattering. I usually dont go for the snake oil in a bottle but you have nothing left to loose..

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[TravisB]

I'd change the trans fluid filter, it might be packed up with ****, just a thought. Thats the easiest place to start

Any whining from the fluid pump?

It sounds like its just low on fluid, you sure the level is correct?

No noticeable noise from it other than the delay to engage which I agree seems like a low fluid situation but it read good on the stick. I will look into changing the filter and replacing the fluid.

 

[DoubleDingo]

4 quarts may not enough, but is a good place to start. I wouldn't try moving it much until you are sure the fluid level is correct. And change the filter.

 

[Dmack]

I think they take up to 10 quarts if the converter was drained also. Just agreeing 4 may not have been enough.

 

[animal]

Merged the duplicate posts to keep all replies Thanks for the heads up!

 

[Bextreme04]

No noticeable noise from it other than the delay to engage which I agree seems like a low fluid situation but it read good on the stick. I will look into changing the filter and replacing the fluid.

Did you check it while idling in park? Warm or cold? If all the fluid leaked out and its been sitting for years, it's possible the pickup tube O-ring is shot and its just sucking air too. Make sure you start it up, cycle it through each gear manually for a few seconds, then return it to park and go check the fluid level.

 

[Matt69olds]

Make absolutely sure it’s full of fluid before trying to move it. If it was really low on fluid the damage may already be done.

If it’s full, most likely the forward clutch is smoked. The forward clutch is engaged in every forward gear. Drop the transmission pan, if it’s full of crud, it need to come out for a overhaul.

The transmission addictive MIGHT help if the forward clutch won’t engage due to hard seals. However, nothing can put the friction material back onto the clutch plate.