I've read quite a bit on changing the diff-mount and I just broke mine last week after I installed my KTS suspension and was checking wheel hop.. Well, I dreaded doing it but I found myself without a choice. I have supplied some crappy photo's from my iphone, sorry for the glare.. But I read alot about all the things you would have to do, loosen this take off that.. Well I tried to find an easier way to get it done, I spent about 2-3 hrs finding an easy way with minimal parts removal. I found it pretty successful, but I'm sure a few others would yawn, but I figured it out and I hope my terrible narration helps someone tackle this job..I should have taken more pictures so try to use some imagination. I tried lol.

Some of my MOST helpful tools were a short 17mm socket, 2 floor jacks, and some wobble head extensions (these were the key for me) a serpentine belt wrench, a set of gear wrenches, and an impact gun..


I started by lifting up the car pretty damn high..CHOCK THE WHEELS!


I removed the exhaust from the down pipe back...


Removed some of the heat shield and disconnected the drive shaft(not remove it), left it hang..


In anticipation on dropping the subframe, I placed a jack under it to lower since I had no idea how fast it would drop. IMHO, I dont see a reason to loosen the half shafts from the diff.. just loosened the e-brake (I hope you chocked the wheels lol) and everything flex's as the diff moves, plenty of room..


The only bolts/nuts I loosened on this entire job, were the 2 large nuts holding the subframe and the 2 small ones holding the bracket that was also held by these 2 same large nuts. not to mention the stuff holding the drive shaft, heat shield, and removing the diff-mount, geez..


Something that I learned that caught me off guard was there is a small lip on the diff mount that kept the subframe from dropping completely, I made the mistake of assuming it was not going to fall any further and removed the jack, and when I removed the part of the mount bolted to the subframe, the subframe fell the rest off the way down ontop of me. Yea, pretty dumb, but thank god it wasnt that heavy and didnt pin my arms down. So let this be a warning to anyone attempting to do this themselves at home.



Back to it! After the subframe is lowered, you should be able to get that wobble extension with that short 17mm socket on your impact gun and loosenit..this is the rest of the way the subframe dropped when I loosened those 2 nuts on the subframe side..


After the broken piece is removed from the subframe, and its lowered a good bit, you should have plenty of room to remove the rest of the broken mount from the diff, this is where the gear wrenches prove their worth!


After you've installed your new mount to the diff, put that jack back under the subframe and start lifting back up. You gotta line them long studs back up to go into the subframe(picture #7), I found this the hardest part in the whole operation, and even that wasn't that bad, have a pry bar or equivalent handy! Here's a trick on what I did, after I had the studs through, I threaded the nut on about half way so that I still had clearance to line up the diff-mount to the sub frame. Its slotted if you havnt noticed that in this process so it should be easy to line it up. get them as low as you can in the slotted hole, I did this using the jack. (just like in Picture #4) there should still be enough room for you to be able to reach your fingers in there to get that socket on the nuts (you wont be able to using the extension) after you get the socket on, direct the extension from the outside of the car, through the space left between the subframe and the body, and tighten them nuts. I don't know the torque but with the extension I tightened them with an impact gun. After its all tight, lift up the subframe completely with the jack, re install those bracket things to the ends of the subframe and tighten it back up and finish re assembling the drive shaft etc. That should do it. Clean up your crap and go for a ride! Some say stock diff-mount is better than the competition. I bought the competition diff-mount from Mazdatrix, and I look at it like, its cheaper, its stronger, and ANYTHING is better then that f**king CLUNK!! This guide worked for me, this is how I did it. I don't know if it will work for everyone. This is my first ever guide for anything, if anyone wants to try and clean it up or add there input feel free. I hope this helps!!!!

 

nice write up.... but dont be cheap... get some jack stands for christ sake.

 

LOL I figured someone would notice.. but this is what I use when I work on machine's in the field. I'm a caterpillar field mechanic.. They work great on heavy equipment..

 

nice write up, I have to do this on both of my 7s soon.

 

you should have installed a pinion snubber to prevent any future failure of that mount. i went thru 2 of the mazda comp mounts and finally on my third mount i had enough. never ever will i have the same problem. good write up BTW.

 

Thanks guys I appreciate the compliments. I've herd of this snubber but only vaguely.. What is it? I might install it anyhow. I don't ever want to deal with this crap more than once.

 

https://www.rx7club.com/showpost.php...0&postcount=22

 

Holy crap dude, I can't believe that subframe fell on you. Jeez reminds me of the whole stock catback falling down on me when I was taking it off. Good thing you lived to write about it : )

 

Man, thats all those things are. I can get those at my job! Why didnt anyone think of this sooner..

 

I enjoyed the write up. I did mine a couple of weeks ago. I replaced the side mounts with solid ones from supernow and did the front with the mazdatrix comp. This inspires me to do a write up on my next mod... thanks

 

I almost had this happen to me when a buddy and I were doing a clutch job on an EVO. You have to drop the subframe as far as you can to get the transaxle out. We dropped it too far and I felt the subframe hit my hair, little power steering line bracket saved my dome.

 

Yeah, let me know what you did I think I'm gonna do them too..


good so i'm not the only one lol

 

I pulled the diff, and used a rivet gut to push the stock bushings out but it took forever and some muscle just to get one out, the other one I got a solid steel rod and hammered it out, which was alot easier. It actually took me less than 90 seconds. Just dont use a chisel cuz u run the risk of hittin the cast aluminum which we know doesnt share the same integrity as steel.

Make sure and double check you have the supernow ones the right way before you push em in, they go in with a few lights taps. By now, you know how to it back on, I did the job by myself (pushing the diff up from the floor, and bracing it with my knees- cuz a friend flaked on me). After this mod you actually hear the diff now. Im gonna start moddin my car again soon, and Ill start takin pictures of all of my steps

 

i agree... if anyone ever has to pull their diff for anything they should put a pinion snubber in.. its cheap and easy.. takes like a half hour and saves your front diff mount... i love mine

 

sounds like this is something ill have to do when i pull mine soon!

 

I'm waiting for a good one to pass by at work and I'll add the pics to this thread, if anyone else doesnt do it by then so its one bid howto type deal.

 

is the pinion snubber necessary on a stock n/a s4? or is it more for the 7's putting down power?

 

I would regardless. I have a friend of mine that has an s4 n/a vert.. His broke.. If you plan on having some power..I'd consider it definitely..its a cheap +!