Hi all, I'm looking for a used pumpkin to replace the current one. It has 200k on it and it started humming recently. The car us a 2003 LS 430. I've replaced the oil to see if there would be any change and there wasnt. Also the oil at the bottom of the diff was black and sparkly - so something is getting ground down.

I'm in the Austin area, looking for a low mileage or rebuilt diff - I'm not aware of any specialist that would sell Lexus diffs around Austin - let alone rebuild them. Does Anyone know a shop I could reach out to?

Has anyone done this before? Is it something one could do in a garage with limited tools?

Thanks for the help!

 

Be sure its actually the differential before you replace it. It may be one or more worn or defective tires that are making the noise. Put another set of tires on the rear, maybe just move the front tires to the back, and see if the noise changes.

 

Agreed with Jabberwock, how do you know it's the rear differential? I also had a humming sound in the rear, turned out the rear wheel hub basically split in half internally. Check for play in your rear wheel hubs. DIY labor on that was a pain!

 

All four hubs have been replaced recently, so they shouldn't be the issue. I've had the tires inspected at Discount Tire, who said they're looking great. The shop who did the hubs had the car on a lift and checked the fluid (he cracked the drain just a bit to see the color of the fluid) and it came out black & sparkly. When he checked the top, the fluid was clear and yellowish (like it's supposed to be).

At this point even if it's the tires -- the differential is DEFINITELY trying to destroy itself

I'm trying to keep it on the road, but if parts like these keep failing - I'll have to get rid of it.

 

Most likely these are the tires producing the sound, however, it could be defective or low quality wheel hubs. Long time ago I installed moog brand hubs in the front (easy DIY plus cheap price), right after installation I could hear the noise coming from them. Learned my lesson and switched to Timken and Koyo.

Which brand was installed in your case?

 

Do you hear a difference in the hum between acceleration and coasting. A bad diff. usually changes between them.

 

There's not much change when coasting, at least no noticeable pitch changes.

 

Ok, now there's a noticeable change - the hum gets louder when off gas.