SPL diff bushings
 

I broke my rear diff bushing a few months ago, and I had a set of these bushings laying around (never got to install em on my 350Z). Can't have the diff flopping around like that so I dropped off the car & some parts at jnaut's shop (J Spec Auto). J Spec Automotive Inc.

Yep, solid aluminum diff bushings from SPL. These are a set made for a 350Z but I had Jason aka jnaut squeeze them into my Z. What a royal pain in the *** these were. It took quite some time & effort to remove the rear bushing. Squeezing the aluminum bushing was slightly less annoying (but still a pain the ***). NOTE: The 350Z bushing was slightly oversized and needed some work to be squeezed into the 370Z subframe. Installing the front set were cake by comparison. The entire rear subframe had to be dropped from the car to get the job done. And yes an alignment was needed afterwards. Perfect opportunity to install a set of rear camber arms.

How do they drive? I picked up my Z from the shop and went on a 180 mile road trip to the other side of FL. DAMN these bushings are LOUD. Any and all gear whine is transmitted throughout the entire cabin. Certain mph ranges are worse than others but highway speeds are tolerable. Note: I had Jason install another pumpkin with 4.08 gears at the same time. These gears had a little bit of a whine (in comparison to my stock 3.7 gears). On the brightside, shifting seems smoother but then again I had all the fluids replaced for this visit as well. No wheel hop on the street. Car feels planted onto the road.

The road trip gave me some time to think about what to do about this? So I grabbed a sheet of 45mil (approx. 1mm) thick EPDM rubber liner and gave it to Jason to squeeze between the bushings & subframe in an attempt to quiet down the noise. He ended up putting a few pieces between the subframe and body as well to reduce the noise. In the end it helped. Noise was reduced and now it is liveable (but still noticeable over stock). Would I daily drive the bushings w/o the rubber insulation? HELL NO. Would I daily drive with the rubber insulation? Yes.

Props to Jason @ J Spec Auto for all this work done to my Z!!! I had decent amount of work done on this visit and the car feels awesome. THANKS!!

http://jspecautomotive.com/

PICTURES!!!!!
http://www.the370z.com/members/tranc...me-off-car.jpg

http://www.the370z.com/members/tranc...ushing-out.jpg

http://www.the370z.com/members/tranc...-gonna-fit.jpg

http://www.the370z.com/members/tranc...g-1mm-time.jpg

http://www.the370z.com/members/tranc...nally-twss.jpg

http://www.the370z.com/members/tranc...t-bushings.jpg

CLIFFS NOTES:
-stock bushing is a piece of sh*t
-SPL aluminum diff bushing set (from a 350Z) adapted to my Z
-350Z bushing is slightly larger diameter than 370Z bushing
-removing stock rear bushing sucks hairy ballsack
-installing aluminum rear bushing sucks hairy ballsack (could have been avoided if I had access to a lathe)
-installed bushings feel great but noisy as f*ck
-fitted 1mm sheets of EPDM rubber between subframe & bushings and between subframe & body; helped make the noise tolerable
-should be less noise w/ stock gears
-I wish I knew someone was working on a set of urethane bushings earlier

So the 350z bushing is not the same size as the 370z? Or was it just sanded down because it was difficult to install?

350Z bushing is:
1) slightly larger in diameter (requires some machining)
2) slightly longer, not important, it just sticks out a little bit on our subframes

Just contact SPL for the 370Z specific kit, or wait for a urethane replacement set. I didn't feel like waiting for the SPL bushings and already had these on hand. Someone had to try it. :icon14:

Thanks again to Jnaut, I would have burned my car to ground out of frustration if I attempted this myself. :icon17:

I'm just worried about the bushing comming off of the subframe. I want to do this myself, hope it goes smoothly.

from what i saw, it was a ton of fun getting the stock bushing out. i'll let jnaut chime in and put in his 2 cents. :icon17:

Out of curiosity.....how do you break a rear diff bushing??

good question. i have no idea how i did it.:confused:

everyone that i know personally who has done it either has FI and/or track abuse (1/4 mile).

or drives it like he stole it*

You can also break it if you like going sideways.. true story.

or driving iit the way it was meant to be driven! :icon17:

Damn... I got out of my car today and heard some hissing coming from the rear.... Looked under and saw oil dripping on the hot exhaust.....hoping extended warranty covers this....:(

UPDATE

Swapped out the SPL diff bushings for the urethane Whiteline bushings. It's a night & day difference! And I think the Whiteline ones are a bit cheaper too. I wish I knew about these before I installed the SPL ones.

How was the fitment? Did you have to modify it to fit?

We used a 350Z kit. 350Z rear subframe has a slightly larger diameter rear diff bushing (just a few thousands of an inch). the front bushings are identical.

we already cut a little bit of metal (a few thousands) in my rear subframe to fit the SPL aluminum bushing so the urethane one went in like butter. I don't see a problem squeezing in the SPL bushing if you have not done what I had done already... it will compress slightly to fit in (unlike solid aluminum).

So if I read this thread correctly, if I wanted to just to replace my old bushing and install a new urethane Whiteline bushing in my 370z, I am still going to have problems with 1) removing the old bushing and 2) installing the Whiteline one since it is for a 350z (like the SPL version)? Is that correct? From what I can tell no matter what, I will need to shave the subframe right? :confused:

Removing the old bushing will be a pain.
The Whiteline should slide right in.

^yup what he said. if you can get that far with the install, the few thousands of an inch difference shouldn't be a problem. the real problem is getting the stock bushing out.

Just out of curiosity, what conditions caused you to check your bushings in the first place. Was there extra noise coming from the diff?

rev out first gear then powershift into 2nd gear, I felt a clunk and slight noise from the rear end. then I looked under the car, and the telltale sign was there... black fluid dripping on the diff cover. I expected this to happen eventually so I knew to look/wait for it.

Just an FYI - I talked to Sean at SPL Parts and they do indeed have all the new bushings needed for the 370Z diff. No shaving needed for the install of their parts. They just don't advertise very well I guess since some of you have gone through a lot of bull sh*& to get the sub-frame bushing out and buying other 3rd party 350Z parts to make all this work. I will be buying the kit later this week for my diff seal rebuild. What the heck - the diff is going to be dropped no matter how you slice it to replace my "breathing" oil leak issues on the side seals so I might as well replace all the OEM bushings that are going to wear out sooner rather than later - to hell with the noise. Give me track time.

My next question is does anyone know the fastest/easiest way to get that bad boy bushing out of the sub-frame? Seems that is the hardest one for replacement. :confused:

Drop the subframe to gain access to the rear diff bushing.

Then, since it's all apart install SPL Chassis subframe bushings and optional knuckle monoball bushings.

Noise be damned :driving:

I don't find the SPL solid AL rear diff bushings to be t0 loud...Yes, the rear diff drivetrain noise will sound like woo, woo, woo every ~0.5" @ ~40+ mph (my350Z also supports this claim); inherent in teh rotation of the ring gear in the rear diff. It's not too loud though! I have a gutted rear Nterior trim, Ncluding no d0Nut. The strate piped Xhaust w/bullet mufflers drowns out the noise....Of course I don't daily drive my Z34, but for a "for fun" weekend car these bushings R "teh shizer!" I highly recommend 'em to anyone looking to cure the dreaded wheel hop...:tup:

yeah aluminum bushings don't work well on a street car, i mean they work great but it will sound like your diff is ready to go. the 350z energy suspension bushings also fit no problem.