I just picked up a 1995 LS400 2LS
the car has 185k miles but i don't know when was last time the diff was serviced
the condition of the car is pretty good but!!!
I been experiencing some weird stumping coming from the rear end every time i come near to a complete stop.
so i decided to service the rear diff oil to no surprise the rear diff oil is very dark and the magnetic drain plug has a fine layer of metal dust.
No big chunks or large shaving thou just fine film of dust.

i change the rear diff with some new mobil 1 75w-90 gear oil.
I hope it will fix the problem.

anyone ever experience this problem? maybe i should try to source a new diff from junk yard?
are the rear diff interchangable from 90-97? or i need 95-97?

 

you would need a 95-97 diff.

 

Does that fluid change require a friction modifier?

 

no, all LS400s are open diff.

 

May also be worth checking the tranny mount, diff mounts and propshaft bushes.
I alway thought worn diffs had a tendency to whine.

 

the engine and and tranny mount are in good condition i already have extra set of mounts on hand if they need replacing.
i took the car for a quick drive yesterday it seem to be much better. the diff before has a clunk feeling like it was locking up when it was coming to a stop. no whine sound.

 

check the trailing arm bushings

 

sounds more like bushings rather than the diff itself. could also be your prop shaft. check for play on the whole drive line.

 

hmm i'll double check the bushing and put up some pictures later.

 

i took some pictures of the rear under carriage.
everything seems to be looking ok
the clunking still persist esp when i come to the quick stop. the clunk only happen around 5 mph - complete stop. it feel like rear end or transmission is locking up.



trailing arm bushing looks ok



The rubber all around the prop shaft mount to the diff is all cracked could this be the problem?

diff mount looks ok also

 

here is a diagram i found on the drive shaft

 

posting pictures of bushings won't do anything, for all the suspension bushings you need to pry on them to apply load then look for cracks. the guibo (sp) bushing in the transmission is a common issue at this age as well as the rear transmission mount.

 

the guibo bushing is #18 on the top diagram correct?

the front guibo bushing is in good condition but the rear guibo bushing connecting to the diff is cracked pretty badly. i already ordered replacement.
the transmission mount looks ok also not crushed as i seen in many threads on here.

why is it call guibo btw? wierd name LOL.

 

IMO the end link in the pic provided looks bad to me but it could just be the angle of the pic. The lower joint particularly.

 

endlink boot is probably about to do and about time for new one.
i just changed out the transmission mount. the replacement was fairly straight forward.
i compared the new one and old mount there is about 0.25" difference in height and the old mount is a bit slanted backward maybe 5 degrees

i jacked up the transmission.
removed the 4 nut that hold the mount to the cross member.
removed the transmission cross member and 4 bolt holding it
removed 4 bolt holding the transmission mount to the transmission
the do everything in reverse.