Rear Differential Bushing Leak
 

So - I saw, what looked to be burnt oil on my freshly installed exhaust system, so I took it to Nissan - A buddy of mine works there - and he said it's the rear differential bushings + drive shaft.

Warranty is covering the drive shaft but obviously not the bushings... My question is - the smart move is to just order the rear differential bushing set off of Z1 Motorsports for $65, instead of $1500 + labor from the dealership - and have a buddy install it - right?

Am I missing something? The Pros of the forum / 370z's are there cons / pros to this route? Should I add anything to this change or replace anything while I'm doing this work already? What's the best route for this?


Here's the part I'm looking at...

https://www.z1motorsports.com/z1-pro...t-p-10356.html


Thanks guys. I am not super smart about all this - just know what I read and see on here!

Did you mess up your driveshaft? The bushing will wear out and pop from normal wear and tear.
Yeah, get some after market bushings and change them out instead of Nissan changing out the whole $ubframe. Its not as hard as alot of people make it out to be as long as you use the right tools and take your time (sawzall is involved and you have to be careful cutting out the bushing collar so as not to put any burrs on the subframe...ask me how I know..lol).

So this all started because I saw that burnt oil/grease on the exhaust.

The car is running perfect other than that. So then they put it up on the lift and saw the bushing and the drive shaft issues.

So I don't know of when / how / or where I would of damaged the driveshaft - the mechanic was vague about the issue - it sounded more of a let's do this to avoid other issues down the road than an immediate issue.

He said there's more oil or 'grease' on it than he'd like to see - He is afraid of it twisting / moving too much - if that makes sense?

It doesn't seem to be a 'pressing' issue but I am warrantied out on it... so I might as well do it - if it's covered.


(I bought this car used with 20k miles on it - the guy got it in 2015 and I bought it Nov 2019 - so it wasn't driven much. But this could of been an issue from the beginning. I got it from out of town - and didn't get my mechanic to look at it before the purchase.)

Thanks for the response!

I guess if its covered then get it changed out. You didnt feel a vibration, hard to turn, weird noises etc? Unless they saw that it was chipped, or something.

You might also want to weigh your options on the bushings. SPL solid bushing seem to be the favored bushing. Some have even gone SPL everything with their suspension (Rusty).

Oh, and after the bushings are replaced, change out the diff fluid, falls under the "while im at it" situations.

Naw - so no issues. No chip - no nothing - He just said it looks quite greasy - as in it may be leaking? I wish I knew more about drive shafts! ha!

also - can you link me what you would get - the z1 motorsports SPL solid bushings don't say they are usable for the 370z... Am i missing something?

And yeah I'll do the diff fluid also. Thanks for the tips - I'm down to do whatever else if it makes sense and while I'm at it category :D

It's a 2016 nismo with 30k miles on it.

Drive shafts dont leak...can you ask your buddy what exactly was wrong with it?

Just do a search on Z1 for 370z diff bushing. Youll even see the type of diff fluid to use. If you REALLY want to do more than just maintenance, you can get a finned diff cover for better cooling and slap on a diff brace..

Whiteline makes a great diff bushing set also.

Yea - I'll check with him tomorrow. I"m sure I just didn't get something right on it and I'm mixing the drive shaft issue up with the bushing issue.

I'll check into those diff parts also - once I talk to the performance shop that's going to do the install.

Appreciate you taking the time to help!

That big old bushing is filled with silicone, not grease. And it's nasty. When that bushing goes bad. It normally leaks down the diff cover. The bushing has 2 chambers filled with the silicone. Only one chamber normally lets go.

I've installed 3 diff bushings so far. 2 SPL's and 1 Z1. The SPL's were easier to install. They're a solid bushing, where the Z1 is poly. The poly moves around during installation. The poly transmits less vibrations.

Alright so yeah - Silicone leaked down my Diff - thought it was diff fluid.

So Rusty - which bushing do you suggest? If install isn't an issue?

I like the SPL's. But that's me.

Question. You do have the black streaks on your diff cover? Correct? The reason I ask. Some have blown gear lube out of the breather hose. The end of the breather hose is on the driver side of the sub-frame. So, it will drip on the exhaust on that side.

yeah - here's what it looks like

Yep, diff bushing.

To change to bushing out. You're looking at at about 6 to 8 hrs of work. Depending on skill set. To drop the diff. You got the exhaust, drive shaft, axle shafts, frame bracing, sway bar. It's best to work from the front of the sub-frame. Install the new bushing from the front. Push it all the way in. Until the front of the bushing is flush with the sub-frame. This should get you where the diff should be. Bunk had to drop his diff a second time, and push the bushing a little deep to get the front 2 bolt holes to align up.

Thanks man. What a pain in the ***. Damn Nissan. Why even allow this out on these cars... I've got 30k on the car...

Nissan has this style of bushing in different areas of the car. The lower rear front control arm bushings, the front sub-frame frame bushings.

Crazy....

Here's my next question - Mechanic says I can drive it - and I should be fine... Is this true? Do I need to baby it?

You're be fine. Long as you don't do any hole shots, and side stepping the clutch.

Thanks Rusty. You've been lots of help!

:tiphat:

If you have any more questions. Let me know.

I pushed my Z1 bushing in from the back; used a bigass washer and a piece of angle iron and a long bolt w some washers and nuts and whatnot, and ratcheted it into place. Lots of threads here on ways to do it.

Sent from my SM-G955U using Tapatalk

Don't go to a dealership. Find a reliable, trusted, and credible mechanic. The pics clearly say its your bushing. Your butt and your ears will tell you if there's a driveshaft issue. When bushings fail, dealers will replace the entire assembly vs just the bushing. It is quick and heftier on the cash register.

Good to know!

Thanks - I feel like I’m being had even though it’s a buddy of mine. Seems like it’s more of the protocol - like you said - when bushing goes - they want to replace it all - even if it’s ok.

If warranty doesn’t cover it fully - I’ll be passing on it. Like I said - car drives perfect 👌

If you are able you can replace them yourself. It’s really a lot easier than most people think. I have a video replacing mine on my YouTube channel RiceburnerZ https://youtu.be/aWZI15smSzw

It's easier if you would have gone in from the front. ;)

What about adding a aftermarket diff brace that bolts the diff to the subframe in the meantime so the diff isn't bouncing around in the broken bushing?

Wouldn't this prevent the bushings from breaking in the first place as well?

Yo. I ended up getting some bushings, upgraded cover, and brace from z1 ;) already installed and oh so nice.

Bushings
 

I'm planned on having a Quaife diff put in my base 370z. With the new diff being installed, would installing the Z1 Motorsports Urethane Rear Diff Bushing Set be any more work?

I got the z1 cover + urethane installed - I’m pretty sure it was a smart move to do all at the same time - if you’re having one thing done - might as well have the other.

Get both lsd and diff bushing done at the same time. Since you have to drop the diff anyway. The diff bushing will tack on a few extra hours on the labor. Time to do it depends on your mechanic's skill set.

Thanks for the info guys!

With the diff already out, how come it takes a few more hours to replace bushings? I'm just a noob at this but curious? And I hear a special removal tool is needed?

Nice I don't even want to get to the broken diff bushing saga. Figuring if installing the diff brace it'll save the bushings. :ugh2:

Do a search and it will go into detail about removal of the diff OEM bushing. In a nut shell you will need to remove a brass sleeve when removing the oem liquid filled bushing. Some people press it out when installing the new bushing. My mechanic cut it out he replaced it.

I've done 3 bushings, mine, and 2 members on here. To remove the old bushing. I used a 2" diameter, extra deep hole saw to cut through the rubber and metal inner bushing. Don't use a cordless drill. Use a good plug in drill. You'll be doing some hard cutting. I tried the Z1 removal tool and thought it was a joke. Next was a sawzall to put 3 cuts into the outer bushing shell.Then used a inside muffler cutter to remove the bushing outer shell. Once you got the outer shell out from the frame. MAKE sure that there is NO burrs, boogers or anything sharp inside the frame hole. I used a 80 grit flapper wheel on a 1/4" die grinder. The frame hole where the new bushing will go is NOT perfectly round. Then they welded the sub-frame together. The welding distorted the hole. Something that you have to live with. Grease the inside of the hole up with anti-seize. Grease it good. I found that the solid SPL bushings are easier to install then the poly style. The polys like to squeeze out just before the hole. Also,installing the bushing from the front of the sub-frame is easier. I can remove the bushing in about 20 to 30 minutes. Installing about 1.5 to 2 hours.

The Z1 tool presses the inner bushing out. It's easier to just cut it out.

Note. The oem bushing has 2 chambers that are filled with a black silicone liquid. You HAVE to be careful when removing the inner bushing. The silicone WILL squirt about 4 ft and cover everything when you start to drill or cut through the rubber. :facepalm:

I can tell from the tone, this is experience talking, not some "hurr durr text book says so" moment:icon17: