2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

86-91 Rx7 Rear Differential - Front Mount

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Old Nov 11, 2021 | 01:12 PM
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86-91 Rx7 Rear Differential - Front Mount

++Note...Mechanically Stupid+++

I been having this KICK CLUNK noise coming from back of my car when switch gears. I figured this sweet ride just had to much torque and just wanted to go go go. We put it on a lift and noticed the rear Differential has about 6in of play vertical by hand, Here are pics, looks like a bushing is worn down, trying to figure out the proper part to replace this to fix the issue.

I have had 1 opinion it is the 86-91 Rx7 Rear Differential - Front Mount https://www.atkinsrotary.com/store/8...s-tab-comments

Just trying to make sure before i order the wrong part and waste money, time, and time on a lift. Thank you in Advance



Can see Worn "Bushing here"

from another angle

Can see Worn "Bushing here"
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Old Nov 11, 2021 | 01:26 PM
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Yes, that's the part. It's a common failure on our cars.

Do yourself a favour and install a snubber while you have the mount out. It costs like $10 and adds a bunch of extra insurance for next time. I think the guide is in the archive section.
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Old Nov 11, 2021 | 01:35 PM
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Aye thank @WondrousBread , ordering the part right now, thank you again. So... you know what the part # for snubber is? I had 6 FC stock 25 years ago in my teens and just reliving my teens and the car i have now was all done 4 hours from me so i really am blindfolded with everything unless i take a long weekend and drive.
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Old Nov 11, 2021 | 01:48 PM
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I can do you one better, I found the actual guide:

https://www.rx7club.com/2nd-generati...nstall-867300/

The snubber doesn't have a Mazda part number because it isn't a stock part. It's a mod designed to help avoid ripping the front diff mount.

The stock diff mount has some shortcomings. Under acceleration the nose of the diff wants to pull upwards. The front diff mount bolts to the side of the diff nose on one side and to the subframe on the other side. This means that whenever you accelerate the diff nose is trying to pull upwards, putting a shearing force on the diff mount. More power = faster destruction of the diff mount.

A new mount is the obvious solution, but the added snubber is an improvement. It's basically a little bump-stop that bolts into the car right above the diff nose, facing downwards toward the diff. When you accelerate and the front of the diff moves upwards, the nose hits the snubber instead of being allowed to pull upwards and start stressing the diff mount.

One thing to note is preload: Some people like to space the snubber downward with washers until it touches the nose of the diff. I like to have about 1mm of space between the snubber and the diff to prevent vibration being transferred into the chassis. Not sure if it's an issue but I wanted to avoid that if possible.

There are plenty of V8 swap guys running the Mazdacomp mount + snubber and having no issues, so a new mount (not necessarily Mazdacomp) + a snubber should provide you plenty of security.
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Old Nov 11, 2021 | 01:51 PM
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Well alright alright @WondrousBread , makes perfect sense to me actually, and i will def. do this. Thanks again. new to the forum as a member and im sold on it now.
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Old Nov 11, 2021 | 01:55 PM
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No problem, welcome to the forum

You should take some pictures of your car when you get a chance and add them to the "pictures of your FC" thread in the general discussion section too
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Old Nov 11, 2021 | 02:10 PM
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Yes i will, its been a work in progress and bank account but it fun. Ill try and dig up the old pics also, had 3 at one time in my driveway, at16-19 i never appreciated what i was driving till decades later, back in late 90s you could buy a FC for 3k-5k all the time. Def. miss them days now, they where all grey also, which i dont see anywhere these days.
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Old Nov 11, 2021 | 03:01 PM
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Originally Posted by Alycium007
Yes i will, its been a work in progress and bank account but it fun. Ill try and dig up the old pics also, had 3 at one time in my driveway, at16-19 i never appreciated what i was driving till decades later, back in late 90s you could buy a FC for 3k-5k all the time. Def. miss them days now, they where all grey also, which i dont see anywhere these days.
Yeah, the decrease in availability and increase in price has been pretty surprising. Three years ago I was kicking myself for not selling mine and finding a better condition one, now I'm glad I didn't sell it because I would've been priced out of all the clean ones near me.
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Old Nov 12, 2021 | 11:00 AM
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+1 on the Pinion Snub

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Old Nov 12, 2021 | 02:40 PM
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Just added pics and about me on the new user thread, let me know what ya think.
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