So I just bought my 3rd FC on the 13th of this month(89 GXL w/ 105k 5spd), and it has a clunking noise in the rear end. I can tell its ether the rear diff mounts or the whole subframe. Normally I would get under the car on jackstands and have someone else engauge the drivetrain, but with this being my DD and working almost 7 days a week I really don't have the time so any help would be very greatful!

So is it likely to be one more than it is to be the other? or both maybe?

Thanks again everyone.

 

The rear diff mounts are pretty solid, its usually the front diff mount that will break. I'm not saying it's impossible for the rear to break, but they are pretty solid and would be surprised if it was them...

The same type of mount that is on the rear of the diff is used on the sub-frame, those are pretty sturdy too.

 

It's almost always the front mount. Without dropping the subframe down, it's not usually possible to tell visually if it's broken either. And you'll have to cross your fingers that the subframe tab isn't breaking off as well.

 

thanks guys.

Do you know of any replacements better and stock? MMR only has the rear diff mounts and rear subframe mounts. I'm not necessarily looking for a solid set just something I can count on for years to come, but if solid is the only aftermarket choice so be it.

 

I use the M-Trix comp front mount. Still compliant but apparently EXTREMELY bullet proof as I have been beating the crap out of it for a number of years now....

http://www.mazdatrix.com/G8DiffMnt.HTM

 

exactly what i was looking for! thanks!

 

This should help you out with the install: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/pinion-snubber-diff-mount-replacement-convertible-876959/

 

Got the comp mount in mine too. Launched it a few times every once in a while, and it's held up for the past 1.5 years.

 

awesome, that write up is nice, thanks RotoryRocket. BTW does that pinion snubber sit right above the diff or the front diff mount? i can't really tell from the pic. thanks again!

 

Pinion snubber sits above the diff. I've got a set for sale if you're looking (energy suspension)

 

if the front mount is broken, you will be able to move the front of the diff up and down by hand.

 

Thanks again everyone, I’ll defiantly going to be getting the Mazda comp front mount (if that’s the issue) and the snubbers (I’ll hit you up when the time comes Sharingan, you have PayPal?) the first chance I’ll be able to get under the car is Sunday (working Saturday...) and I’ll try and move the diff by hand (thanks LargeOrangeFont) by the latest I’ll be ordering what I need by Monday if not Sunday.

 

Yep, I sure do. PM me when the time comes.

might wanna check your trans mounts while you're down there. I ended up gettin the whole mmr driveline set (motor/trans/diff) because one motor mount was shredded, trans mounts were sagging and (as a result) the front diff mount was toast. I replaced the rear diff mounts just for ***** and giggles.

 

lol yea last time I was under my car checking why my speedo didn't work (broken cable) I noticed that one of my trans mount bolts was 75% of the way off, after I tightened it, it helped the rear a bit but didn't fix it (I think it had a hand in braking it though lol). This weekend I’m going to order a full set of the Mazdacomps mounts (engine, trans, and front diff). I would like to go with a full poly set like you but this is my DD and I know it would bug me, plus I hear good things about the Mazdacomps, I plan on driving it down to the next 7stock (hope'n there is going to be one ).

 

Oh, mine aren't poly....more like skateboard wheels lol and its my daily driver too. They aren't actually as bad as you might think, its only a specific rpm that the vibration is noticable. Mazdacomp will be fine though and plenty tough.

 

beat me to it.

anyways Im using mmr solid rear diff mounts with an old used front diff mount and haven't had any problems even with some hard launches and auto crossing.