R33 Gtr - Front Diff - Any Easy Way To Tell If Gearing Has Been Changed?

[some_cs_student]

Hi,

In the R33 GTR the rear diff has been rebuilt, its pretty tight so it may have an aftermarket shim pack but appears to be a stock diff (its actually been machined 20thou to loosen it but still locks on most corners at slow speed).

Anyway, I've broken a transfer case, I've still got the parts to it, the shaft that goes to the rear or front wheels, had a piece of metal that broke out of it, the clutch pack itself seemed to be fine.

The symptoms were that of a worn clutch, except very severe at the end (could release clutch and car would not move or stall).

Anyway, is there any easy way to check the front diff gear ratio? To make sure the diff ratios are the same?

Sometimes when on the driveway (slight angle) the front wheels will not kick in until the rear spins a little bit, is that normal with ATTESA?

I had this happen a few times about 3-6months before the old transfer case went so I'm a little nervous, I cannot recall if RE Customs checked the front diff, I mentioned it to them when the transfer case got replaced.....

The front wheel torque gauge does show the front wheels kicking in sometimes, and they are definitely working, just not sure if its working correctly or not....

Regards,

Gareth

[Risking]

Sounds like you have broken the output shaft

Just remove the front diff cover and count the teeth on the crown wheel and pinion gears. Dividing the two will give you the ratio.

[Beer Baron]

Hi,

In the R33 GTR the rear diff has been rebuilt, its pretty tight so it may have an aftermarket shim pack but appears to be a stock diff (its actually been machined 20thou to loosen it but still locks on most corners at slow speed).

Anyway, I've broken a transfer case, I've still got the parts to it, the shaft that goes to the rear or front wheels, had a piece of metal that broke out of it, the clutch pack itself seemed to be fine.

The symptoms were that of a worn clutch, except very severe at the end (could release clutch and car would not move or stall).

Anyway, is there any easy way to check the front diff gear ratio? To make sure the diff ratios are the same?

Sometimes when on the driveway (slight angle) the front wheels will not kick in until the rear spins a little bit, is that normal with ATTESA?

I had this happen a few times about 3-6months before the old transfer case went so I'm a little nervous, I cannot recall if RE Customs checked the front diff, I mentioned it to them when the transfer case got replaced.....

The front wheel torque gauge does show the front wheels kicking in sometimes, and they are definitely working, just not sure if its working correctly or not....

Regards,

Gareth

front diff is not in the transfer case. so replacing your transfer case does not replace the front diff. the front diff is in the engines sump. so if you were assuming that the diff got replaced when they swapped out the broken transfer case I'd say it's unlikely unless the diff was damaged too. and yes sometimes on driveways etc you will get some real wheel slip before the fronts kick in. after all it's an active torque split car, not locked 50/50.

also, you can't just divide the two numbers of teeth to get the ratio. you need to divide one by the other. divide the crown wheel by the pinion. ie 37 tooth crown wheel and 9 tooth pinion = 37/9 = 4.111:1 (standard 32 and 33 GTR).

[some_cs_student]

front diff is not in the transfer case. so replacing your transfer case does not replace the front diff. the front diff is in the engines sump. so if you were assuming that the diff got replaced when they swapped out the broken transfer case I'd say it's unlikely unless the diff was damaged too. and yes sometimes on driveways etc you will get some real wheel slip before the fronts kick in. after all it's an active torque split car, not locked 50/50.

also, you can't just divide the two numbers of teeth to get the ratio. you need to divide one by the other. divide the crown wheel by the pinion. ie 37 tooth crown wheel and 9 tooth pinion = 37/9 = 4.111:1 (standard 32 and 33 GTR).

I think I'm getting mis-interpreted a little here, what I really meant was I broke (past tense and now replaced) a transfer case ~4months ago, its was replaced with a second hand unit.

RE Customs did the replacement, and they did a great job.

I've read, that often the front diff or rear diff may have different gearing, causing the transfer case to break.

The slipping on the driveway, was one of the symptoms I noticed last time, yes I understand its not locked 50/50, and that its variable (in fact I bought a Ruzic torque split controller recently, but that's off topic).

The rear diff has been rebuilt before and appears to be standard, the front diff has never been removed so I'm wondering........is there a way to check if the front diff is running a different gear ratio?

Or do you have to remove it from the car to find out?

I'm just worried about the "what if" the next transfer case breaks....is there anything obvious I can check before that happens?

Thanks,

Gareth

[some_cs_student]

Sounds like you have broken the output shaft

Just remove the front diff cover and count the teeth on the crown wheel and pinion gears. Dividing the two will give you the ratio.

No output shaft is fine, see above post, I'm speaking about the previously broken transfer case, but the past tense was not emphasized in my original post and I cannot edit

There's a front diff cover? I assume its accessible from under the car?

I might try and find it this weekend...

[blind_elk]

Yes, the front plate will be visible and accessible from underneath. Held on by 8(?) 14mm(?) bolts. Don't forget to drain the oil first!.

If you are lucky, you might be able to see the teeth numbers that are stamped on the crown wheel (because it will be difficult to count the teeth on the pinion).