OK, who has worked on a differential?

[Jeff Williams]

The last time I checked, Lola would not spin the Left Rear tire, when I got stuck in my wet grass, while backing up.

I guess I need to do some work on her. Any help would be appreciated.

She is a 1994 Q45t non-TCS.

[elwesso]

I assume the fluid is fresh????

Honestly its probabyl best you dont mess with the differential... BTW theres a great section in the FSM on how to disassemble the diff... not being an a$$ just letting you know... I dont konw if youve ever done stuff like that, but its really put together very precisely.. I mean if Rob's shop who BUILDS DIFFS for a living makes it go boom, you have to assume that that this isnt for everyone...

[DominickJ30]

The Q has a Viscous limited slip differential. Only one side will spin until the viscous fluid warms up. Then you have limited slip.

[Jeff Williams]

SOOOOOO, maybe just a fluid flush and re-fill could fix the problem. I have to confess, I have not replaced all the fluids on Lola yet.

I need to do a dry pavement test, with the car warmed up. It was quite cold, and I was just moving it to a new parking space.

Maybe its not broke.

[maxnix]

The Q has a Viscous limited slip differential. Only one side will spin until the viscous fluid warms up. Then you have limited slip.

Yes, but one greater rotation of one side is enough to heat the fluid to engage (lock) the differential lubricant.

[Jeff Williams]

Would there be clutches in there that are shot, then, or could it be something else?

I recall Dennis saying something about the LSD wearing out, but I could not find the post through the NICO search engine.

I didn't have time to look through the FSM this weekend. I would really like to see some more data posted on the NICO site for those who don't have access to the FSM, or an honest garage.

Thanks.

[RobertsnewQ]

The viscous fluid inside the diff itself cannot be replaced. The oil that lubricates the gears is what you replace.

The viscous fluid breaks down over time and the diff stops working as well.

There is no cure - no internal parts wear other than the fluid.

[DominickJ30]

I think it takes a little more than one rotation.

This is coming from experience in my J, Im pretty sure the Q has the same VLSD.

When I was having fun in the snow last winter it took me quite a couple donuts to get full diff action.

[Rex]

Here's a few of Dennis' older posts I found

IDEALLY Replace the oem rear subframe or just use/modify 300zx parts........and accept the downsides of extreme vibration transmission to body.

Changed my rear subframe when I replaced the diff [due to noise/lack of LSD action] at 235,000 miles [12 years typical life] took two of us 5 hours with a lift and flat transmission jack table and every tool imaginable. Tricky.

Silicone filled bushings are available [from some dealers] for one size of front Q tension rod assembly. Solid ruber and urethane will fit certain sizes.

There are differences between the standard and active Q front tension rods also some TSB versions for caster differences........one size on left different on right.............

Excerpt

... I just flip my trimode to 2nd gear start and proceed with my almost brand new LSD [55k]...........the 20 mm rear bar and Eibach's mean you must avoid abrupt changes in low traction enviroments....

$20 [BG zinc additive] compared to $2900 for a new diff plus labor or $350-$500 plus labor for a used one [that may be worn out [the viscous].

$50+$20 every 2 years [30k] is cheap!

^^ Appears additive is not for viscous LSD, just "rear" ^^

The Nissan Quasi LSD [viscous type] is sealed and need nothing special in the way of LSD additive, unlike most American cars which use clutch type LSD. The Nissan viscous LSD can function nearly as new for greater than 100k unless overheated by spinning tires [on car tire balancer errors] or stuck in snow [but cold so less likely]. Most last 150k or better.

The diff gears need the extreme additive protection of BG concentrate. Unless diff fluid is changed annually..........I use and do both for insurance.

Hope that helps.

[FarFetched]

What you can do is a "LINCOLN" differential. All you need is to pull diff out and use a "Lincoln" welder (or similar) and weld spider gears to the carrier. I've done it on some 4X4 rigs. The problem there'll be no differentiation whatsoever, meaning you wiil wear out tires prematurely but you'll have extreme traction Other side offects might be (if abused) snaped half shafts, u-joints and rubber torque coupling! Other than that it's the way the doctor has prescribed

[q45tech2]

You just find a used low mile diff from a wrecked SOUTHERN/WESTERN Q....[no snow areas]...........don't take their word for mileage go see the donor yourself! Compared to $2500 for a new one a plane ride is cheap when used are $300-$500..........plus install.