I've recently changed my tranny mount, and I was hoping to get rid of a clacking sound when I shift from D to R (and vice-versa), and also a humming sound when I'm at 40mph/70mph (which is really annoying, 'cause it's the speed limit) and luckily the tranny mount just minimized the clacking sound and also the humming but didn't entirely get rid of it. Now, somebody suggested last time I posted that it must be the LSD? What is that, and what does 'LSD' stand for? I wanna learn more about this before jumping into it.

I'm gonna post a few pics later on of changing the tranny mount for the 1995 SC400 since most of the posts here where SC300. It's pretty easy, the only thing that gave me a hardtime was cleaning the metal plate that the mount was bolted to. But I cleaned that mo'fo to its aluminum finish and it looks great now!

 

You do not have an lsd in an scx00 and lsd means limited slip differential aka posi etc

 

Ugh no lsd I have ever had makes any clanking noise but carrier bearings or pinion bearings could have ran dry or low on fluid over the years causing the noise.

 

Does it break or its fixable? Or just need to lubricate it?

 

It most likely be best to buy a good used one which can be had for 100.00 or so.

 

ok no stock diffs make noise just going straight even if its an LSD, which no stock SC has and if you installed one you would know what it is then, i would look elsewhere for the problem, if you have a noise at a certain speed its probably either your tranny mounts, engine mounts, or the driveshaft. do a search these are pretty common symptoms for the sc400. how many miles do you have? chances are if you need trans mounts you need engine mounts too.
https://www.clublexus.com/forums/per...vibration.html

 

Carrier Bearings most likely

 

Well when I changed my tranny mount awhile ago, I kinda figured I need to change the engine mounts too... Will do it it in a couple of weeks 'cause I already scheduled something else for now... And it kinda sounds like its coming somewhere in the driveshaft, so it must be what they're saying, the carrier mounts, which quite frankly is ticking mo off by now 'cause I coudn't find any thread that discusses it, or a diagram I can look at, not even a pic of that damn thing... It's too late to make calls, but when I called Autozone, they don't sell it, but they know what I was talking about...

 

Carrier bearings are inside of the differential. I would check your diff oil and if its level is ok your problem is most likely in the driveshaft. These cars have a bearing mid way on the driveshaft that can go bad and allow the shaft to move under load which causes a clank sound.

 

im gonna throw in a random question since im a few weeks away from purchasing a sc400 shell with hopes that it comes with an lsd rear end. i was under the impression that the sc400's came with a stock lsd (i hope) and the sc300's had the "one tire fire" situation (which is true). so are you saying that ALL stock sc's have this one tire fire? if so where is a good place to purchase an actual LSD since we're on this topic.

 

No sc400 ever came with an lsd so your parts car will not have what you are looking for and you either need one from a supra tt automatic or an aftermarket unit.

 

Snap! I should've listened to my uncle if that's the case! (He's the master mechanic btw) He told me when we where working on the wheel bearings that I'm low on differential oil...

 

Did you put any in ? Now, on these cars with the independent rear end not having any oil in the diff won't make the wheel bearings go bad. They are nonserviceabe, sealed units that can only be replaced, and they never come in contact with the diff oil. If your diff oil did get very low you could have worn out the carrier bearings, pinion bearings, ring and pinion gears, or any combination of those. If you really think the problem could be in the diff you should get someone who knows what to look for to check it out, worn pinion bearings or preload bushings can cause clanking but need experience to check out.