Transmission goes till I whoa's......and when I whoa's it won't go!

Steve C · Dec 14, 2009

I need some automatic transmission advice. Mine is acting strange and I since I am out of work and out of money I hope somebody can tell me that it is an easy fix.

I know it doesnç¨š often happen, but I did once fix a transmission on a 2 speed 61 Chevrolet by replacing a cheap external valve, but that was a while ago.

O.K. This is the story. I have a 2001 2 wheel drive GMC Sanoma pick up with a 4 cylinder engine and automatic transmission. 108,000 miles on it. A couple of days ago I drove out to the barn and used it to bring in some wood pellets. It seemed to work just fine. It was about 10 degrees outside. I let it idle while I loaded and unloaded the pellets because we had to go and run some errands and I wanted it to be warm.

10 minutes later we left for town, we made it about 1000 feet from the end of my driveway and the truck lurched as it changed gears and made a funny noise. Then seemed to be O.K. I stopped for the stop sign that was another 700 feet down the road. When I went to go, it didnç¨š. It was almost but not quit free wheeling, there was a little forward effort but not enough to move the truck.

I put it in reverse and it backed up just fine. I put it back in drive and it wouldnç¨š go.

I then put it in first and it moved noramaly. I got it turned around and headed back for home. I shifted it into 1st then 2dn, then 3rd and then drive and it went just fine.

I have checked the fluid levels and they are fine. I drove it about 5 miles just now it hasnç¨š fixed itself.

As long as I shift it manually it will go up through the gears just fine and the rpmç—´ of the motor seem normal. The torque converter will lock up at the proper times and it doesnç¨š seem to slip, but when I stop if I leave it in drive, it just wonç¨š go. If you know anything about one of these transmissions or have a brother in-law or relative who works as a GM mechanic or a transmission shop, please ask if they know what the likely problem is and ask if it will hurt it to drive it to get it fixed.

I am about 30 miles from the closest independent transmission shop and about 10 miles from a GM dealership.

Thanks guys

ps. when towing the trailer shown in the picture I use 3rd gear as the owners manual suggests. I only use drive when towing if the road is flat or downhill and there is no wind, and no downshifting or converter unlocking going on.

dodge man · Dec 14, 2009

I'm no expert and I know nothing about your truck in particular, but it doesn't sound good. I always start cheap and easy, such as a fluid and filter change. Sometimes all the worn clutch and band material can clog up the filter. I once had a 72 Plymouth that I thought I was going to have to rebuild the tranny on, and I changed the fluid and filter and adjusted the bands and it worked fine after that. The problem is that I don't think you can adjust the bands anymore on trannies? Someone else may chim in with a little more knowledge.

TCBoomer · Dec 14, 2009

The input sprag failed. The transmission will have to be removed and torn down to repair

Steve C · Dec 15, 2009

TCBoomer said:
The input sprag failed. The transmission will have to be removed and torn down to repair

Thanks Boomer. I don't know what an input sprag is but I sure do need one. I notice that the gear shifter itself seems to feel diferent when moving from the drive to the park position, and from park to drive. It could be just my imagination but it seems to have a mich lighter "detent" between the gear positions and it will actualy go past park to never never land

.

I may have to wait until I am back to work to get this thing fixed. Will it hurt it to drive it to the shop to get it fixed or should I take it over on a trailer?

Do you have any idea what the repairs would normaly cost? $500, $1000, $1500?

clemsonfor · Dec 16, 2009

yea i would say tranny fluid change wont do any good. reason is that it drives if u mannually shift it, needs fluid flow to do this so i dont think thats it. That truck is of age where if its to high you can probly get a junk yard tranny installed for $500-800 just guessing though and that i guess is also going to vary by region?

clemsonfor · Dec 16, 2009

thought you were up north then i looked dont trucks head for the heap earlier there than here in the south cause the rust if so there should be a plethera of then at the yard.

Steve C · Dec 17, 2009

clemsonfor said:
thought you were up north then i looked dont trucks head for the heap earlier there than here in the south cause the rust if so there should be a plethera of then at the yard.

Yes they should, but the people who drive these little trucks up north are frugal bunch and they don't mind a little rust as long as they keep running. I have seem many of them with the cab and box mounts rusted out and the body sagging over the frame but still going down the highway.

They look like they are breaking in half!

aggiehortguy91 · Dec 17, 2009

If your shifter "feels different" and you are able to shift past park, you might have an issue with the shift cable or what ever linkage the truck uses. It is atleast worth a check.

Stimw · Dec 22, 2009

Not familiar with your trans but it sounds like a governor sticking. I had two turbo 400 GMs that the mechanical governor acted up.
Yours should be electronic and might not have a mechanical governor.