My 85 2.8 4spd makes a deep clunk sound whenever I move her from a stand still and also when I put the clutch in while I am moving. I thought it would have something to do with the Dog bone so I changed that out for a poly mount but it's still making the sound. Any ideas?

Also just for my own knowledge, How tight should the bolts be on the dog bone? I figured once the bracket that connected the bone to the engine started to compress that it was tight enough, is that right?

Thanks.

I hammer down the bolts with a 3/8" drive impact generally. But then again, I am lazy!

And the clunk... does it also happen when you use the engine to slow you down? it could very well be a loose engine mount, ripped trans mount, or maybe even cradle bushings rotted. Also don't forget control arm bushings back there.

[This message has been edited by Racing_Master (edited 06-15-2011).]

Motor mount. They are rubber and they rip open......I think I have a picture of one of mine here someplace.....

[This message has been edited by Gall757 (edited 06-15-2011).]

quote Originally posted by McCool: Also just for my own knowledge, How tight should the bolts be on the dog bone? I figured once the bracket that connected the bone to the engine started to compress that it was tight enough, is that right? Thanks.

Crank it right down, the bracket needs to compress so the metal teeth on the dog bone bushing sleeve grab into the bracket and prevent movement. The poly version may not have teeth on the bushing sleeve, just gotta depend on it being very snug.

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Crank that dog bone down or your motor mounts are shot. It is hard to tell if they are bad until you unbolt them since there is an engine holding them together.

I too agree that the most likely problem is either an engine mount or a transmission mount, although when mine was clunking it turned out to be a bad CV joint. You can test for a worn CV joint by jacking the rear end of the car up, putting the parking brake on, grabbing each axle (not wheel) separately and trying to turn them back and forth. If one or the other, or both of them rotate even a little, then the CV joints on that side is worn out. If that's the case, the clunking you hear is the internals of the joint smacking back and forth in the excess clearances as the drivetrain is loaded and unloaded during shifting.

An easy way to both tell what and how bad it is:

With it idling in neutral pop the decklid. Grab the throttle cable by hand and rev it. Your engine will most likely move considerably. Not only should you be able to see if its the dogbone but you should be able to track down where the clunk is coming from. If you have a helper it is fairly easy to track done which motor/trans mount it is if thats the case.

Some motor mounts (I think the stock ones as well) have a safety interlock that in spite of the mounts failure is meant to catch the engine. They clunk pretty good. If it bucks as well when you are starting out or has bad vibes when cruising at a constant rpm or engine braking this is a likely culprit. They can all be changed with the cradle still in the car (on the 4cyl anyways not sure on the 2.8) though some are easier than others.

One (or more) of the lower mounts is probably trashed. You can get an indication of this by putting the transmission in gear (with the engine off), and rocking the car back and forth by hand. Have an assistant push the car back and forth while you look / listen into the engine bay. If the clunk comes from the passenger side, it'll be the lower engine mount. If the driver's side, it'll be one or both of the tranny mounts. Along with the clunk, the engine and/or transmission should also visibly shift its position.

And if it turns out to be a tranny mount, just replace 'em both. Because if you only replace one of them, the other will probably fail soon.

Best of luck!

[This message has been edited by Blacktree (edited 06-15-2011).]

mine has the same clunk noise, i looked from under the rear bumper to see the front engine mount was mutilated from all the oil my engine likes to throw.

My valve covers used to piss out oil, so I guess it probably is the mounts. I'll peek my head under the car tomorrow and check her out.

Another question; If I do change out the mounts, should I stay with the rubber or should I go poly?

well, you could.

But, when i was more interested in cars, i had read that you should buy the rest of the poly mounts, since the stiffer mount would put more stress on the other rubber mounts.

But you never know, it could've been marketing talking.