Vibrations in drivetrain

[mrnapolean1]

I just replaced the Transmission mount in my truck. It was broken and was causing a strong vibration while accelerating or slowing down.

That has been fixed but now the vibrations are when accelerating down the road it goes hhhh thh thh thh hhhh.

Or to better explain: Like a shopping cart wheel that has 3 flat spots after each other.

Would this be a transmission or something in the differential or driveline?

Truck Information:
Year: 1987
Make: Chevrolet
Model: R10
Trim level: Single cab, Short Wheel base, Base trim (rubber floor mats, no AC, etc)
Tire condition: Great (Replaced all four 2 months ago) Tires are properly mounted and balanced.
Tire size: 235/75/R15
Engine: Chevrolet 262 CID 4.3L V6 (Rebuilt about 50k ago)
Transmission: I think its a TH350 but IDK. Pan looks like one off a TH350 my dad owned back in the day. All I know is it has 3 speeds and NO overdrive.

 

[chengny]

Maybe look at the u-joints. That's a good place to start. See if they show any excessive play.

A really worn u-joint can be identified by just twisting the driveshaft and watching the u-joint. If you can move the driveshaft at all without the connected shaft moving along with it, the universal joint needs replacement.

The next step is to stick a screwdriver into the opening in the u-joint and pry against the spider (the cross piece) - any movement of the spider within the yokes is reason to replace it.

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[mrnapolean1]

Maybe look at the u-joints. That's a good place to start. See if they show any excessive play.

A really worn u-joint can be identified by just twisting the driveshaft and watching the u-joint. If you can move the driveshaft at all without the connected shaft moving along with it, the universal joint needs replacement.

The next step is to stick a screwdriver into the opening in the u-joint and pry against the spider (the cross piece) - any movement of the spider within the yokes is reason to replace it.

You must be registered for see images attach

The vibrations don't happen when the transmission has been shifted to neutral.

I can manual shift 1 and 2 but when I shift from 2 to D it starts the vibrating thing again.

Some small vibrations are present while the transmission is shifted in 1 and 2 but not near as much as D.

So I eliminated the Driveline and the differential. But I will check the U joints as they havent been replaced in awhile.

 

[83kid]

The vibrations don't happen when the transmission has been shifted to neutral.

I can manual shift 1 and 2 but when I shift from 2 to D it starts the vibrating thing again.

Some small vibrations are present while the transmission is shifted in 1 and 2 but not near as much as D.

So I eliminated the Driveline and the differential. But I will check the U joints as they havent been replaced in awhile.

If it doesnt happen when in neutral, it means that the problem is with the driveline, not from the engine or anything

 

[mrnapolean1]

If it doesnt happen when in neutral, it means that the problem is with the driveline, not from the engine or anything

So in fact the transmission might not the culprit?
Do you think I should replace the Driveline from one from a scrapyard?

 

[350runner]

I would follow @chengny on this....

Sent from the dust in front of you!

 

[Lastwords]

The u joints change how they vibrate or if they vibrate with the amount of road and speed of rotation. I had a ranger that drove fine till about 60 then sounded like it would tare itself apart. It would smooth out a bit as the speed increased. U joints were chewed up.

 

[one4fun]

I would follow @chengny on this....

Sent from the dust in front of you!

Agreed.

 

[mrnapolean1]

I have pulled the Driveshaft out of the truck.

The rear U joint that connects the drive shaft to the differential had a cap that was so wore out that there where no needles left in it. about half of the cap was gone as well.

I am having the U joint replaced and I am going to request to have the old one back so I can show yall how wore out it was.

These U Joints do not use the clips so I am incapable in replacing it myself.

 

[chengny]

If you have a big vice and two sockets of the correct size, you can them to change that type of u-joint:

One socket - with an ID slightly larger than the OD of the cap - goes on one side

Another socket -with an OD slightly smaller than the ID of the yoke bearing aperture - goes on the other side

Set the yoke in the vice with the sockets positioned as below:

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and really CRANK DOWN on the vise jaws. It might take some heat and penetrating oil but the caps will eventually give and the one under the big socket will pop out.

There are several more steps to this procedure but I'm sure you get the idea.

 

[79K10]

on the old '79 I used a socket and a BFH against the floor to change all mine... ya ya i know... lol... not the best solution, but when your budget is $0 and need it done yesterday, you do what you have to do. ... also watched utube vid or two ...a vise is my advice ... lol whats the book charge in a shop? it'll be at least an hour of labor, right maybe 2

 

[79K10]

...

 

[mrnapolean1]

I got the Driveshaft back from my local mechanic.
I put it in and took a test drive and there are still vibrations present but not near as intense as it was before.

I looked at the other U joint its seems fine for the moment.....

 

[one4fun]

Have you replaced the tail shaft bushing and bearing?

 

[mrnapolean1]

Have you replaced the tail shaft bushing and bearing?

No.