Is my GS300's rear diff on its way out ? (Video inside)

mullingar

I have a 98 Gs300 with 130k and for a long time I have felt a clunk from the rear end of the car when I reverse out the driveway and hit the go pedal when in D.

Thinking my rear diff is on its way (or any shafts/spines etc), I got under the car and propped up the diff input and one side of the output to stop them moving, I then rotated the "free" wheel back-forth to see where there was any play.

Here is a video of the play within the diff, apologies for the low quality (iphone video was compressed for youtube)

https://www.youtube.com/watch?v=mnbfgHBJwEk

Any thoughts?

Voodoomelon

Not exactly the same thing, but it sounds familiar, take a look at this post:

http://forums.bimmerforums.com/forum/showthread.php?t=1502504&highlight=cv+joint

Could be a drive shaft joint alright, possibly CV joint.

mullingar

Voodoo, some good pointers in that link, but I have isolated all the driveshafts/cv/propellor. What you see moving is the output plate of the diff which then connects to the driveshaft

mullingar

Just to visually help on the description, here is a pic of a diff removed from a GS300



(plus a shameful pump)


Edit,

It looks like there is a spline where it meets the driveshaft output called a "Differential Side Gear Shift"

http://bahamutcars.free.fr/workshop/GS_97-05/rm/rm588e/m_sa_0060.pdf

I need to pop the rear cover off the diff, and see what is happening, I hate Diff oil

Voodoomelon

Hmm, just thought i'd post that link, I just remembered reading about it, I won't be much help on this, sorry.

v300

The clunk on this diff can be mostly cured by getting the diff reset up to close to factory standards. This would involve a new crushable flange and checking where the input shaft pinion and crownwheel are mating and shimming and adjusting them closer together. For what It's worth my old TT Aristo (a more powerful Lexus Gs300, but with two turbos etc...), which I sold to a mate in Mullingar strangely, enough had a lound clunk between reverse and going forward from the diff for the 5 years I had the car, it never got worse, and that car got driven hard. I put in super hypoid 140W gear oil and it made zero difference either way

I'd recommend living with it for the moment, but only because it's a Lexus...

mullingar

Thanks for that v300, but doesn't the aristo have a LSD?

You are probably right but I think I will just hunt for a good low mileage second hand diff next year as it still works fine, its just the clunk.

but only because it's a Lexus...

To me it will always be a glorified Toyota (with all the toys) as the only difference between a NA Aristo and a GS300 is just a badge, the Aristo was manufactured first!

v300

mullingar wrote: »

Thanks for that v300, but doesn't the aristo have a LSD?

Some do. Some don't.
Mine had a factory torsen diff, so no clunking or jumping on tight corners.

It just had the ever present clonk from the play in the pinion and crownwheel (common to both diff's with, and without a tricky centre diff') upon changing from reverse to forward, and vice versa.