The Stovebolt Site Forums The Shop Area General Truck Talk Drivetrain questions!

When I 55 in drive it will not proceed to go forward with out me giving it gas. Then when I let off the gas it stops. Shouldnt a vehicle start moving forward on its own when put it drive? I have already checked the brakes. I am running a "trans am" rear end with full posi.

Have you checked the wheel bearings & the rear end bearings? Have you done any work to the drive line?

Could be when you 55 in drive. I'd check the muffler bearings and have the johnson rod adjusted.

On a serious note..maybe you have a high stall torque converter?

I have not done any work to the drive line. I have recently purchased this truck that has been sitting for nine yrs. Now I am trying to work out all the quinks!!! I did add gear oil to the rear end it was almost a quart low.

Somethings dragging. Usually brakes, but not always. Drive it a bit, then start feeling/smelling for a hot wheel is one way to check. Another is to place the vehicle on jackstands and turn the wheels by hand, listening and feeling for something dragging.

Fred, I have done that. If fact my truck is on stands right now. I have the brake drums off the rear end. So I know its not the brakes. Tonight I am going to disconnect the driveline form the rear end and turn both the drive line and rear end by hand and see which has the most tension.
I will keep you guys posted!!

Is it the truck in your pics on webshots?

If you didn't put the drivetrain together, I'm with rsg2506 on this one. I think the torque converter has too high of a stall for the engine.

Hy guys just what trans are we talking about here, the factory hydramatic, or something else. The hydramatic uses a fluid coupling not a torque convertor.

i was also thinking about the stall convertor.

I believe the trans is a 350 but I am not sure. I will check the numbers over the weekend. However I did disconnected the driveline at the rear of the truck. I was able to turn the yolk with not much tension. Then I turned the drive line with my tranny in neutral and it had quite a bit of tension. Should a tranny spin freely with no tension while in neutral?

4.3in84toy - This is the truck in those pics!
Thanks for you input!
Much appreciated!

I think you have found the culprit. I figured when I saw the pics someone had started a "hot rod" project and you are having to fix everything they lost interest in.

I see so many of these stall converter issues at the shows. Some dingaling in a chevelle has a small block with a radical cam and a stall converter that makes it almost undriveable in the car corral, so he spins the engine up, spins the rear tires and slings gravel all over someone else's car.

Partly cause it ain't easy to figure out which stall converter you need and mostly cause people think, "If a 2400 stall is good, a 3000 stall is better."

Sometimes trial and error is the best process, but that's expensive and tedious. Just as you thought, when you put the vehicle in drive on a flat roadway, you should have just the slightest amount of creep or forward momentum on a driver.

Do you know the specs on your engine? Post them here and I'll try to help or even better call TCI on the phone and they will tell you what stall you really need.

I dont realy engine spec's. What I (visualy) know is:
-350 small block
-202 double hump heads
-Edelbrock Performer Intake
-Edelbrock 600cfm carb
-HEI Distributor
-Mild Cam (what I was told)
-The truck as alot of low end. But as I get going down the road it has no power.
But its hard to hear the motor. The PO has some straight pipes coming out of the collector. They are about 3'-0" long and loud as hell! Im worried if my tranny is bad.

I was also told the truck has 350 hp. But I dont feel 350 hp when I drive it. I mind keeps leaning towards my tranny. I just hope its not that. I can not afford to fix that right now.

Trust me rogpatt if you had 350hp you would know it! A good stall converter for these animals is anything bewtween 1800 and 2300. 2300 is good for road but will also give you a good launch!

I would get those pipes fixed you might not have enough back pressure good for dirt track racing tho!

popcorn The Truth is Out There (Keep us posted this is interesting) Ben

Okay fellas, I had my truck up on jack stands and put it in drive with the tires on. The tires did not move with out giving it gas. Once I gave it a good amount of gas they turned. When I let off they stopped turing. Here's the "kicker". When I put it in reverse they turned without giving it any gas. Im alittle confused now.
Please advise!!!!!!!

don't know about stall speeds and such w/ automatics, but remember that reverse is always waaay lower gearing than 1st/low

Bill

Well, I went back and re-read the thread and I thought the problem was your rear brakes. In the event that you didn't check the rear diff here's some ideas. I'm thinking it's the rear diff.

Take off the driveshaft and try turning a wheel. Is it hard to do?

Also, check the backlash in the diff by wiggling the input yoke. I bet you that there's more than a quarter inch rotation before the rear wheels start to move.

Check and see if the pinion nut it loose. It's most likely the culprit. It's located inside the diff's input yoke.

Zeke

Check your pinion bearings-if one of 'em is going bad,it'll "cam up" in drive,and loosen in reverse.
Speed

By "cam up",I mean it'll try to push all the bearing's rollers together and wedge itself,causing lots more drag on the gears.
Speed

"Okay fellas, I had my truck up on jack stands and put it in drive with the tires on. The tires did not move with out giving it gas. Once I gave it a good amount of gas they turned. When I let off they stopped turing. Here's the "kicker". When I put it in reverse they turned without giving it any gas. Im alittle confused now.
Please advise!!!!!!!"

Well, you may not like my thoughts…I think the trans may be toast. When you gas it to go in forward, do the RPM’s flair up, then you move, but in reverse you just move? Makes no difference to a stall converter if the trans is in forward or reverse, the flywheel and input shaft always turn the same direction. Reverse gear ratio on a TH350 is in between first and second, so I don’t think that’s a factor. (1st= 2.52, 2nd=1.52, 3rd=1.00, and reverse=1.93) Check the fluid, is it low? Fluid should be hot for most accurate reading, the cooler it is the lower it will read, but some should always show on the stick. (Vehicle must be running in park or neutral while you check it). Look at the color of the fluid by dripping some off the dipstick on a white piece of paper. It should be red-ish, not brown. Smell it, it should not have a strong “burnt” smell. Also, I think that there is what’s called a “sprag” (one way roller) that’s in play in forward when you start out. (In the transmission) It could be slipping/failing. But if you pull the shifter into manual low (all the way back/down) a clutch kicks in to hydraulically hold low gear. You could see if that makes any difference.
Anyway that’s my two centavos.

I was a fraid that it was the tranny. I just picked up another one and will swap them out with in the next couple of weeks. I will let you all know how everything turns out.

Even if the trans is dead, check the specs on the converter. If the PO was hod-rodding, you may still have a converter with a higher stall than you want. No point pulling the trans twice!

Good luck.

I been watching your post. Have you or anyone else changed the filter in the trans recently. There is a small gasket between the filter and the valve body, that sometimes slip to the side when you put on a new filter. If it does this it will block off part of the oil going though the tranny. I'd pull the pan and check and see if its something this simple. This is a 350 tranny problem, you never see it a 400 tranny.