Installed NEW rear diff mount.. STILL CLUNKS! HELP! WTF? Urgent! car still on jacks
 

I installed the new rear diff mount. the old one was worn out to where we could bend the rubber part with force taking the nuts/bolts off. Now it does drive a lil stiffer and when shifting it doesnt do it as much, but still when i throw weight onto th rear i hear a THUD, not as much now since the new diff mount is on.. What else? My brother says its the struts?

thanks guys!

did you replace the two diff to subframe mounts or the front differential mount? maybe the trans mounts are bad?

i really didn't look for that. But EVERYONE was like 100% the rear diff mount is the problem even mazdatrix said that was the issue. Now i feel like the car is 75% more tighter and goes into gears better and doesnt THUD when boost kicks in, but still in some shifting it thuds and the sound is coming from the very back of the car.

5 hours of working on this and still thuding.. man am i ever so angry. Please everyone tell me what you think is going on.

and yes it was the rear diff mount i replaced, and the old one was still in 1 peice, but i could bend the rubber when i was loosing the bolts on it.

:( im just sad now. because i haven't a clue what to do now. And i dont want to take it to a shop here in orlando 1) because i dont know any that have rotary techs, and 2) I dont want to waste what little cash I have.

Time to do the subframe and diff mounts. I'm sorry it wasn't 100% the front diff mount but it does sound like it was on its way out.

Generally when you hear a thud in the rear of the car during hard shifting it is the diff front mount. Its located near were the rear drive shaft mount is (above it). The two rear round diff mounts usually don't go bad, but if you already replaced them then cool. If not, don't worry about those unless they look bad (these can be a bitch to replace). Another cause from clunking could possibly be the rear tranny mount. Sometimes if the car is really old, or if the car has a rear camber rod installed the rear subframe leaves little room for the diff to wiggle and will cause clunking as well. You can get an aftermarket diff snubber to fix it. And.. the last set to worry about and the least likely the sub frame mounts....

~Mike.............

You know the cheapest place to find those parts.

AND what i replace whats the REAR DIFFERINTIAL MOUNT the $99 from mazdatrix that has the 5 bolts.

could it be the struts?

how hard is it to replace tranny mount or that snubber thing?
Thanks for fast reply

You have been a huge help , i couldnt of done the rear diff mount so fast and easy without your guidance with links of info. Can you help me via AIM with links again. Your a rex7 saint ;( lol

Trans mounts are simple, use a jack to support the trans and just drop the crossmember and replace the mounts.

Tranny mount not hard at all. Probably 9 bolts/nuts max to get the bracket off also.

Tranny mounts is a good possibility, even a u joint.

I also thought U joint but I would think he would have a vibration issue at speed also, which he doesn't.

Well everyone i'm kinda confused now... The trans mount? The sound is at the very end behind the seats, sounds like right in the middle of the back where the rear struts are in the middle of the back hatch floor, like its hitting under that and smacking it. This is my only daily driver ... only

its off the rack now. So anyone who can hit me up on AIM and kinda more deeply help me figure out my problem, ill even paypal ya for help.

check your tires lol i tought i had poped my diff but in reality i had a tit on my rear tire

Did you check for play in the driveshaft?

No i didnt. how should I do that? just push it up and down after jacking the car up?

get underneath the car and try to wiggle the driveshaft, some play is normal but you will know its not normal. where in central fla you live? i used to live in clewiston.

im in altamonte springs around off I-4

well anyways I hope i can with as little as money as possible already paid cash for the car.. fix this rear end thuding. 99% would of been just rear diff mount, replace it.. damn it still thuds. but atleast not nearly as much and it doesnt thud when boost kicks in, only when the rear is force with downshifting.. and well you can put it in like 4th going 30mph and throttle it in and out full/none/half throttle and it will knock nasty.

Dude, a broke spring will cause something like that as well.

I've changed the diff mount on my T2 and it clunked, partly because of the camber adjuster. I raised the front of the subframe enough to give little room for the pinion of the differential to move under sudden torques.

The solution: Install a pinion snubber.

https://www.rx7club.com/showthread.p...pinion+snubber
http://www.v8rx7forum.com/v8-rx7-tec...ion-again.html
http://www.v8rx7forum.com/v8-rx7-tec...n-snubber.html

After this, your car should have no problems with clunking. The v8 guys swear by this modification.

I haven't heard clunking in mine since the install, even under hard launches, bucking intentionally in 1st, etc.

installed pin stubber... WOW IT STILL CLUNKS!!! W T F

You keep saying how you replaced the REAR DIFF MOUNTS. The problem sounds liek a FRONT DIFF MOUNT issue. did you mean to say you installed a front diff mount? Those are $99 from Mazdatrix.

Did you preload the pinion snubber when you installed it? Even with a factory diff mount, the pinion will still snap up to some degree under hard launching. People using the single rear camber adjuster rod will run into clunking as well, since the pinion is moved closer to the floorpan. Preload the pinion snubber and you should hear very little to no clunking.