Omni A525 Dogbone Mount Problems

[85GLHT-Omni]

I replaced the dogbone tranny mount in my TII omni this weekend, a week after installing it. It failed bad, a NAPA replacement part made of cast aluminum, the top lobe cracked off and was missing. This type of failure has been an on going saga since upgrading to a TII.

To be specific, this is on an 85 GLHT with a TII and A525. The dogbone connects the rear differential cover to the K-member through two bolts and clevis-like brackets. This mount conteracts most of the torque made by the engine. Vibration and shifting are greatly effected by this mounts performance.

I've gone through two OEM-style mounts, both failing in the rubber part and one cast aluminum part (above). I've also tried the Polybushing's version, but the vibration was unbearable.

I understand that the A525's life is limited at the HP and Torque levels I'm running, but I am trying to put off the A555 upgrade and bobble strut mount as long as possible. What else can I try or what am I doing wrong?

Also, is there any other supplier for this mount? Anchor doesn't carry it and PepBoys, Advanced Auto, Autozone, and all my local shops only carry Anchor. NAPA was the only store that could special order one...and even that was a challenge.

[tryingbe]

Junkyard...

[Turbodave]

What condition is your front (under the radiator) motor mount in? A new poly mount up there might help take some of the load off that rear mount. Also make sure that front mount bracket is tight to the trans, those bolts tend to loosen over time.

[Clay]

Easy solution: http://www.polybushings.com/pages/mopardogbone.html

[GLHNSLHT2]

+1 on checking the other mounts as well as getting Johnny's poly mount.

[85GLHT-Omni]

I own a Polybushings dogbone mount but the vibration was excessive...all my fillings fell out. The mount peformed beautifully and there was no engine movement during acceleration.

The front mount is visually okay, although I have a MP replacement ready to install. I've also checked the front mount bracket bolts as one had loosened itself several months ago.

I may try a poly front mount. Is this typical? Is there anyway to put a bobble strut in?

[The S is Silent]

I put in a mopar replacement this weeked...fun stuff. Like putting 10lbs of crap in a 5lb bag.

You should change your mounts anyways. Chances are the mounts have never been changed and these cars are getting up there in miles. The rubber in my front mount looked ok, but as soon as I removed it...it was fugly. The rubber was really soft, and wasn't really helping any.

[supercrackerbox]

Yes, the factory design is practically worthless compared to the PB one. I've chewed up so many of them in my '86 they're practically a maintenence wear item.

If the vibration was too much with the PB dogbone, then I'd just warranty the NAPA one again, and get a PB front mount. That front mount alone will do wonders for limiting the torque rotation of the engine and keep a lot of the stress off of the dog bone. Then when you upgrade trannies, you can install either a factory or PB bobble strut and you should be golden. I have the PB front mount and bobble strut on my Shelby Z, and I can't imagine how I got along without them before. Since the bobble strut is adjustable, the vibration is a non-issue.

[85GLHT-Omni]

When I R&R the front mount, do I need to remove the entire front bracket? I believe, there are four bolts/stud on the forward part of the bracket, and two or three bolts connecting the tranny to the mount. Any tips?

[turbovanman²]

I am currently using an OEM Omni dogbone in my van, its been in there 6 months and still good to go. I noticed the other day that the AWD 2nd gen Minivans use the same dog bone and it looks identical in size and length to the Omni, might want to check into that.

You have to remove the front mount/bracket completely, as you need to remove the mount insert and install the PB or MP insert. When tightening it back up to the block, push the bracket against the bell housing and tighten the block bolts snug. Properly tighten the bellhousing bolts then loosen and properly tighten the block bolts. This makes sure its square and seated correctly so it doesn't crack.

[85GLHT-Omni]

I found the problem today...

Front bracket was held on by only one bolt, the other two bolts were missing. The bracket was cracked and missing a piece near the third bolt hole (axial). I repaced the mount with a MP mount and through bolted with the two transverse transmission bolt holes.

It's like I have a different car, shifter feels great, no more of the vibration.

[Turbodave]

I love it when I'm right


Glad you found the problem, now more seat time and less creeper time...

I check those bolts on my car at every oil change, had them come loose too many times before.

[Force Fed Mopar]

Heh, I guess I should check those front bolts on mine, haven't checked them sice installing the engine 20k ago. I have noticed a little more engine movement through the shifter, but my dog bone is junk too.

[The S is Silent]

Heh, I guess I should check those front bolts on mine, haven't checked them sice installing the engine 20k ago. I have noticed a little more engine movement through the shifter, but my dog bone is junk too.

I just replaced those bolts on my van. Lock washers and loc-tite were in order this time around. I've also thought about putting in longer bolts and putting nylon lock washers on the other ends. That f-er wouldn't go anywhere.