94 GMC Sierra 3500

[DoubleK]

I just bought a GMC that is a 94 model. Single axle 1 ton 4x4. 350 with automatic transmission. My question is this. It had been sitting for 3 years and the motor was locked up. I had that fixed and after driving back from the mechanic's shop, the darn thing will not shift out of 1st gear. I have replaced the speedometer sender, and the speed buffer and it still doesn't shift.

The guy I bought it from swears up and down that he did not have any problems with the tranny, just the engine. I have an estimate of $2100 to rebuild it but, I am concerned that might not fix it as it might be electrical.

It has 177,000 miles on it and is a pretty good old truck with a dew eze bed on it.

Does anybody have any suggestions?
I need to start using it to feed with.
Dub

[cfpinz]

I just bought a GMC that is a 94 model. Single axle 1 ton 4x4. 350 with automatic transmission. My question is this. It had been sitting for 3 years and the motor was locked up. I had that fixed and after driving back from the mechanic's shop, the darn thing will not shift out of 1st gear. I have replaced the speedometer sender, and the speed buffer and it still doesn't shift.

The guy I bought it from swears up and down that he did not have any problems with the tranny, just the engine. I have an estimate of $2100 to rebuild it but, I am concerned that might not fix it as it might be electrical.

It has 177,000 miles on it and is a pretty good old truck with a dew eze bed on it.

Does anybody have any suggestions?
I need to start using it to feed with.
Dub

Might not have, but three year's worth of sitting around could have caused them. I'm not a GM person, nor do I know squat about automatics but if you intend on keeping the truck a while I'd spring for the rebuild from a reputable transmission specialty shop. But first I'd take it to that shop and have them diagnose it, could be as simple as linkage problems. It concerns me the mechanic who rebuilt the motor didn't attempt to fix the problem.

[JHH]

I just bought a GMC that is a 94 model. Single axle 1 ton 4x4. 350 with automatic transmission. My question is this. It had been sitting for 3 years and the motor was locked up. I had that fixed and after driving back from the mechanic's shop, the darn thing will not shift out of 1st gear. I have replaced the speedometer sender, and the speed buffer and it still doesn't shift.

The guy I bought it from swears up and down that he did not have any problems with the tranny, just the engine. I have an estimate of $2100 to rebuild it but, I am concerned that might not fix it as it might be electrical.

It has 177,000 miles on it and is a pretty good old truck with a dew eze bed on it.

Does anybody have any suggestions?
I need to start using it to feed with.
Dub

Check the Trans fuse. And which trans does it have in it? 4L80E ? Or has someone swiched it to an old 350 turbo?

[JHH]

Does the speedometer work? I f the speedo does't work it wont shift right.

[grannysoo]

Another thing that you might try is to get a quart of K&W Trans-X to go into the transmission. You will find it at most any auto parts store (Part # is 2032).

Automatics sometimes get something hung in the valve bodies that prevent it from shifting. Trans-X helps dissolve solid particles in order to make the fluids flow. It also has a money back guarantee, so if it doesn't help, it won't cost you anything.

[DoubleK]

Trans-X did the trick, that is a miracle salve.

Thanx Grannysoo, I owe ya

Dub