Hi,

I have 4.08 gears on my HR 350Z.

The final drive was noisy at first...I went to the track and the diff oil burned...

The oil was new, and after 2h30min of track, with 30 min sessions, it was black, thick and the smell was horrible... It was litterally burned...

I returned the diff to the man who did the job in order to set it right.

Now, the diff is a lot less noisy but on certain speed i can hear it...

One question for your guys. What is the normal temperature of the diff in normal and "sporty" use ?

Today i ran the car for 1 hour, 30 min of normal driving then 30 min of sporty driving, then i measured the temp of the diff right after with my IR thermometer. (temp measured on different external spots of the diff)

The highest temperature was 105°C (221°F).

Is this temperature normal ? I assume it will be higher on the track since higher speed and constant full throttle...

Ps : 75W140 Castrol Syntrax oil (the oil which burned was Motul SAE90, i took a higher grade)

 

Did you go thru any kind of break in procedure? If so what was it?

I actually just installed a quaife in for a guy with the stock 3.5 gears. A 20 min 80 mph cruise down the highway yielded temps around 160-180°F via an IR thermometer. 70-80 second Auto-X flogging this weekend only resulted in 140°F temps.

My 4.08 gears with a quaife ran around 180°F after a 45 mins highway drive to AutoX this weekend (10k miles on the setup) to give me my IR gun back at the track and checked the temp for fun). If the gears were noisy from the get go I would bet he did not set the gears up correct. Unfortunately you've already broken the gears in with the incorrect gear mesh so you should have gone thru a second round of break in procedure after he made corrections.

Hard to say if the pinion depth is off, backlash, or bearing preload is wrong.

I had a mild gear whine when my gears were being broken in, now its pretty darn quite for a car with solid alum. differential mounts.

 

I have driven around 700km with the new diff setting...

For you how long does it take to break in a diff ? For me it should be ok now...

If i remenber correctly, in normal driving the diff temperature is around 85-92°C (180-195°F)

Considering the AutoX, is way too short to show any high temperature, and the speed is also low compared to track sessions of 20-30min...

 

I drove today 40km on twisty roads, between 30-70mph with quite a lot of moderate accelerations.

The diff was around 85°C after that...

Does it seem normal ?

Ps: Do you have the "stock" diff cooler in US (i mean the small radiator on the oil pan, i don't know if this is the correct term in English).

This one :




If not, my temperature is way too hot since we have it on european cars

 

That's 85°C = 185°F which seems okay.

The temperatures on both cars I reference have the finned rear cover like your picture. This is an performance part sold by Nismo, not OEM.

 

it seems this diff cover comes stock in Europe.

I'm going to the track the 29th of June, i will take the temperature under track abuse