something is loose when hard accelerating

[1972BlueC20]

I've had this issue for a while now when I floor it from a dead stop....something feels loose in the drivetrain (maybe)

My suspicions are motor mounts, trans mounts, u-joints or carrier bearing....LOL

It's hard to describe, but something def isn't right when taking off fast....I think its from the flexing of the engine or driveshaft

Anyone ever experience this or have any ideas??

[Fitz]

Originally Posted by 1972BlueC20

I've had this issue for a while now when I floor it from a dead stop....something feels loose in the drivetrain (maybe)

My suspicions are motor mounts, trans mounts, u-joints or carrier bearing....LOL

It's hard to describe, but something def isn't right when taking off fast....I think its from the flexing of the engine or driveshaft

Anyone ever experience this or have any ideas??

Yes. They are called TIRES. They turn too fast, make screeching noises and lots of white smoke.

Or, perhaps you should check your passenger side motor mount.

[1972BlueC20]

LOL @ Fitz


How do you check motor mounts?

Is the passenger side more prone to going bad more so than the drivers side?




Thanks,

[leftybass209]

your engine naturally wants to pull, so one easy way (but not foolproof) is to obviously do a visual inspection, but you can also pull your throttle from the carb while watching the engine. I'm not saying it's the best way, but I've been able to find a broken mount like that, albeit, a different vehicle. Best of luck!

[Fitz]

Originally Posted by 1972BlueC20

LOL @ Fitz


How do you check motor mounts?

Is the passenger side more prone to going bad more so than the drivers side?




Thanks,

Have a friend or your wife get in the truck and start it. Raise the hood and stand to one side. I like the left side. Have the person in the cab stand on the brake HARD, put it in gear and blip the throttle lightly with the other foot. If the motor rears up, the passenger side motor mount is broken. That's the one that has to fight the engine torque so it usually breaks first. if it's gone be sure to buy both left and right. It's an easy fix but you will likely have to jack up the motor on each side to get the old ones out and the new ones in.

My tires are the clutch that protects the rest of the drivetrain in my truck on hard starts, hence the flippant answer.

[1972BlueC20]

hahaha Thanks Fitz!

When jacking up the engine, how do you do one side at a time?

I thought you put a block of wood between the jack and pan and lift up....is this correct?

[GASoline71]

Put a blcok of wood between the jack and the pan. If you have a busted mount. That side will raise.

Gary

[Fitz]

Originally Posted by 1972BlueC20

hahaha Thanks Fitz!

When jacking up the engine, how do you do one side at a time?

I thought you put a block of wood between the jack and pan and lift up....is this correct?

Correct! Your method is better than mine. You'll have to release the bolts on both mounts before lifting and all you really need is to get the weight of the engine off the mount, not raise the motor much at all. 1/8th inch should do it. I usually use a pry bar but that can get a bit clumsy if the truck is not on a lift.

[Keith Seymore]

Do you have a two piece prop?

Even when new and everything else is fresh/correct some trucks have a "launch shudder" on hard acceleration or heavy loads (like pulling a trailer).

Typically it's right after the vehicle starts rolling and you'll get three to four kicks (might even feel vertical in nature) in the seat and then it goes away.

If that's the case it is pretty much inherent in the driveline design. You could try shimming, going to a one piece, or not accelerating so fast.



We were able to fix some trucks by lengthening the front shaft (moving the center support rearward) and shortening the rear shaft the corresponding amount, but I don't imagine you are able to get into a full fledged vehicle development program.

K

[1972BlueC20]

you mean 2 pc drive shaft?

If so, then yes....I have a 2 pc driveshaft with carrier bearing

[Sklptrljay]

I've had two carrier bearings on two different trucks go bad, and that definitely could do what your describing. Have you visually checked it?

I had one where the bearing itself was wobbly, which sounds like maybe what's happening to you. The other one broke the actual mounting plate off, that one was not a subtle noise and/or hard to diagnose. KER-PLUNK-KER-PLUNK-KER-PLUNK-KER-PLUNK!!!