Diff Breathing a ...lot of oil

[Kinkstaah]

Diff Breathing a ...lot of oil

Hi Folks.

Recently got a 1.5 Nismo diff (non pro).
Seems to be breathing quite a lot of oil. Couldn't really find any information on whether this is normal or not. Haven't had it a long time so turning to the SAU brains trust to see if anyone's seen something similar here.

Haven't beaten SUPER hard on the diff. Little bit of hill driving, little bit of track day, (but the picture was before the track day). Car is used as a daily.
I believe the oil is "Total" and it's an 80-90W oil that was put in when the diff was put in. Is this getting too hot and causing it to essentially breathe everywhere?

Worth changing to an 80-250w or 80-140 LSD oil like the Nismo one?
Note: Diff IS in an auto, so you get a lot of torque down low with not a lot of speed thanks to stall converter. Unsure if that changes things, prematurely heats things, or anything.

Any alternate solutions? The oil was bad enough for a suspension place to think it was a leaking shock when it was actually diff oil over everything.

[Dale FZ1]

After a weekend at the track, I get a bit of an oily sweat on the diff - via the breather.  Kaaz 1.5 way.  And it gets a fair old workout.

Checking levels there's no obvious amount lost.  A little bit of oil on hot surfaces and being fanned about by airflow goes over everything. Think what happens in a kitchen environment. Do a regular degrease and monitor levels via the filler plug.

[Duncan]

I don't think breathing is that unusual, and particularly with redline shockproof.

I run an extended breather in the race car and have no issues, so either go that way or just clean the underside and top up the diff every now and then

[V28VX37]

Greg I'll have a look at mine when I get the car back from the shop, same diff (haha). Where does the breather sit?

Silly question but what tool do you need to get the top filler plug open without pulling the diff out? I tried at some point and it's so close to subframe a normal socket wrench wouldn't go in there, and extender didn't work either.

Also off topic but if anyone knows where to get a 1/2" drive to metric Nissan filler plug adapter I'd love to have one, my gearbox plugs are mangled now from spannering them directly with a 1/2" drive...

[Duncan]

you want something like this:http://www.ebay.com.au/itm/Laser-Tools-Drain-Plug-Key-8-13mm-Sq-1578-/380694570644?hash=item58a32a2694:g:pXcAAOxyD9JSA6YZ

13mm square drive drain plug tool.

I bought a whole kit but have never used any o f the other fittings.....

The breather is a fitting on the top of the diff on the right side rear. Looks like a little cap but the top part opens a couple of mm under pressure, assuming it's not blocked.

[Kinkstaah]

I did wonder if it was maybe over-filled, in the 34 (sedan at least?) the breather is directly connected to the inside of the chassis rail, so it's clearly 'supposed' to vent there. I'm happy to just keep cleaning it but thought it best to confirm. After sandown there was maybe a drip or two but nothing compared to what there initially was. So I am assuming it may have been initially over-filled an has now become... less over filled..

Is it worth changing the oil to something 'known' like the OS Giken or Nismo oil? If this is fairly typical then all good, it didn't affect anything under there functionally so I'm not so bothered if it's not going to cause something to go bang

[Dale FZ1]

An "unknown" oil like Castrol LSX90 will do the job more than adequately for a fraction of the cost, added bonus you can get it nearly anywhere, anytime.

(and you could substitute that brand with Penrite, Shell, etc. of a similar spec)

[Kinkstaah]

The oil in there currently is Total 90w-140 apparently. If I ever change it and it makes a notable difference I'll update the thread. I hadn't even heard the brand before it made its way into the diff, but I agree that some oils seem to get "Brand power" from seemingly nowhere.

[Dose Pipe Sutututu]

(feel free to ignore as this is just a guess)...

perhaps the backlash isnt' adjusted properly, i.e. too tight and it's causing a fair amount of friction thus cooking up the fluid...

 

I run the Nulon 80W140 LSD oil and it barely breathes much.. I do get some vapour like others have mentioned after a good day of punishing the shit box at Wakefield. Last track day, manged to do 84 laps

[V28VX37]

I just checked and my Nismo 1.5-way came new with 'Nismo Competition Oil Differential 2189E 75W140 by Motul 100% synthetic'. I'm not sure whether this is intended just for running it in, or full time use, guessing the latter.

So from a viscosity point of view your oil seems fine Greg.

7 hours ago, Dose Pipe Sutututu said:

(feel free to ignore as this is just a guess)...

perhaps the backlash isnt' adjusted properly, i.e. too tight and it's causing a fair amount of friction thus cooking up the fluid...

I run the Nulon 80W140 LSD oil and it barely breathes much.. I do get some vapour like others have mentioned after a good day of punishing the shit box at Wakefield. Last track day, manged to do 84 laps

An interesting point about the backlash, my workshop guys said that they got lucky with the centre and the shimming/adjustment was spot on first go. Apparently these can be a bit sensitive.

84 laps is totally crazy, wish my car could do that!

[V28VX37]

I've just ordered some Motul Gear Competition 75W140 100% synthetic off eBay. It's half the price of Nismo Competition Differential Gear Oil - 2189E 75W140 100% synthetic (made by Motul), which doesn't really make sense to me but oh well. My hope is that it's pretty much the same oil.

[Sick_R31]

If it says nismo on the box idiots will pay more for it.

[ichi-go]

Possibly overfill, mine does it as well as it has the greddy diff cover which increases the diff oil capacity and causing alot of froth in the diff itself, heard it's pretty common if you use the greddy diff cover

If it's happening to your car alot, just setup a diff catch can, pretty common on 4wd owners if you look it up....

 

 

[KiwiRS4T]

On 10/23/2016 at 0:54 PM, V28VX37 said:

I've just ordered some Motul Gear Competition 75W140 100% synthetic off eBay. It's half the price of Nismo Competition Differential Gear Oil - 2189E 75W140 100% synthetic (made by Motul), which doesn't really make sense to me but oh well. My hope is that it's pretty much the same oil.

If you read the spec sheets you will find the Nismo stuff is in fact different (although also made by Motul).

[V28VX37]

27 minutes ago, KiwiRS4T said:

If you read the spec sheets you will find the Nismo stuff is in fact different (although also made by Motul).

Thanks, good to know! I've now got a bit of a mix in the diff (~1L Motul, rest Nismo leftovers from the original bottle), hopefully that's ok?

Looking through the specs it looks like Nismo is the same ester-based 100% synthetic base oil as the Motul but with some nitrogen additives. Also the Nismo is to be changed every 3,000 kms. Sounds pretty voodoo.

http://www.nismo.co.jp/en/products/competition/of/competition_oil/lineup/75w140.html
http://www.nismo.co.jp/en/products/competition/of/competition_oil/lineup/basic.html

vs

https://www.motul.com/ro/en/products/oils-lubricants/gear-competition-75w140
https://www.motul.com/system/product_descriptions/technical_data_sheets/108/original/Gear Competition 75W140_GB.pdf?1290086772

[GTSBoy]

5 hours ago, V28VX37 said:

 Also the Nismo is to be changed every 3,000 kms. Sounds pretty voodoo.
 

 

How many cane toads were licked before they came up with that recommendation?

[Kinkstaah]

I'm bumping this because well, fkit I couldnt find anything on search and this thread is all about me and my diff.

In the years since this started, the following things have happened.

1) Went manual. No difference. Still Clunky Clunky.

2) Drove three other Nismo 1.5 ways, one in a 32 GTST, one in a 34 GTT, and the one in the S15. All of these were acceptable in terms of clunkiness leading me to believe mine was toast somehow.

3) Got the entire diff pulled down and rebuilt for $800. No problem was found and they said it was pretty much as-new inside there.

4) I have found no posts ever to insinuate Nismo diffs get more worn and more loose over time.

5) Car now has a V8 infront of it and it is still clunky as ever, maybe more so, because dat torque is more noticable at 10kmh. Running OS 250R fluid.

1) Do people use LSD additive with the OS Giken fluid? Is it worth trying? I am going to try it anyway.

Is there any other reason anyone can think of why my diff would be more clunky than others? I have replaced every bush in the rear end of the car, and the problem still exists. Backlash was adjusted when the diff was rebuilt, as it was entirely disassembled (I saw it all laid out on a table) at the time to "try and find the problem" of which there was no evidence...

Can anyone think of a reason why it would overheat and vomit tons of standard viscosity fluid (80-140 etc) that works fine in every other 1.5 way?

[Duncan]

So 2 problems; still breathing way too much oil, and very clunky?

I think the key test was point 3. A diff shop should immediately if there has been some issue with clearances too tight or loose causing binding/overheating/whatever, but they say it is as new. So basically that covers off about 99% of internet mechanic opinions about it being a diff issue.

Re the breathing oil, from the posts above it looks like that settled down after first track day, is it still a problem? If so I can only suggest extending the diff breather.  Attach some hose to the breather fitting and run through a loop or 2 of hose to one of those tiny air filters, up high in the boot somewhere (considering what is underneath it if it does actually leak of course!). This might prevent a lot of leaking because it takes a lot of froth to push up, around a loop, and out a breather so the oil generally drains back down again once it all settles down.

Re the diff being clunky...without being too simplistic that is either inside or outside the diff. Inside you can pretty much rule out a clearance issue assuming the diff shop is competent, but it could still be a really tight centre. Outside, every point between the flywheel and the tyre has potential slop, it is more than simply bushes. Also check cv/shafts, unis in tailshaft, even subframe and engine mounts.  

But the key test with driveline clunks is whether it clunks on and off the power in a straight line (slop somewhere) and clunks because the inside wheel is jumping in turns (tight diff). On and off the power at slow speed in a straight line will help diagnose which it is

 

[GTSBoy]

I'm increasingly of the opinion that the splines in the hubs are to blame for a lot of the clunk. Add that to all the other little slops. I also wonder if the back end of the gearbox contributes. Because I've had similar experience with trying to get my S15 helical set up nicely in my R32. Spent to get it put together right the first time. Tried to find the clunks. Spent more to get it pulled apart (different shop, for independence) only to get the "It's not the diff" report.

Le sigh.

[KiwiRS4T]

3 hours ago, Kinkstaah said:

1) Do people use LSD additive with the OS Giken fluid? Is it worth trying? I am going to try it anyway.

 

The OS fluid is made for the LSD so I don't see why it would need an additive. I used the Nismo competition oil in my GTR mechanical LSD and didn't change it in over 20,000km.

Have you checked the diff temp on a track day? Can you get (if it hasn't already got one) a finned backing plate for better cooling?