Slow_go_400

Hi,

I'm currently performing major maintenance on my 96sc400 with 210K miles on it. The shop called me and said I better take a look. When I got there I saw the pan with all the diff fluid and it was silvery with metal shaving.. I had recently changed my diff at 190K due to it started hearing poping, which was replaced by the lexus dealer with used stock diff I got from NIX99.

I got to admit I did not take care of my first rear diff. But how come my the 2nd rear diff went bad so quickly? Arent these diffs pretty solid.I know your suppose to change rear diff every 15k-20km, but having the 2nd diff going bad on me soon . What else can be wrong? Might be stupid question. Does the drive shaft have gears that connect to the diff that may have already been bad from the first failure?

Oblviously since I'm going to change the diff anyway, I might as well get an LSD, so looking for the cheapest solutions

-Try to get an used TT Auto LSD ... So far not having any luck finding one
-Get an TRD LSD for around 950$ from suprastore or titan and use the stock pumpkin.. If I do go this way what else will I need?
-Just bite the bullet and buy a new LSD 3.76 Torsen from a toyota dealer

Any feedback would be appreciated. Just want to make sure this does not happen the 3rd time.

Sc dRifta

u got pics of the oil ?its ok to have little shavings if the diff is new and needs to be broken in. the ring and pinion gear need to seat. when back lash and pinion depth is adjusted. did u have any driving problems? anyways best bang for the buck is kaaz 2 way DAT3020 id use a sc400 rear end to get better final gear ratio.

ive broken 3 of stock open diffs and thats like trying to drift with a open diff for 6 months straight parking lots and dry lake beds lol how the hell did u break 2 so soon.

O. L. T.

iTrader: (17)

MOVED to the proper forum.

Slow_go_400

WOW .. thanks for the quick reply.. This issue is causing me a sleepless night...anyhow..

I wish I had a camera to show you, but I'm sure its not a simple break in process.. When I saw the drain bolt on diff, it basically looked like a metal fishing reel..

Yes I have traction problems.. When it rains I have to consiously be very easy on the gas, one tire spins so easily and the car gets loose.. (and no I just dont mash on the gas)

I have never heard of Kaaz LSD. So I'm going to ask the noob question..They any good? Better than TRD? I googled Kaaz and found them about the same price as the LSD. Also anything else I need? meaning it bolts right up to the pumpkin and drive shafts. Lastly I know with Supra LSD's it matters what gears people here to get TT auto LSD 3.76 or NA LSD (forgot the gear ratio). Do you know what gear ratio the KAAZ DAT3020 comes in..

I do not drive particularly hard, heck I dont even really race.. My frist diff, I got to admit really didnt take care of it, only changed it like once every 50K or 60K miles But this 2nd one I'm not really sure, maybe I just got a used diff with too many miles from NIX99.. Thats why I asked maybe the gear that connects to the drive shaft. I didnt replace those.. (if it has teeth)

Again thanks for reply..

SUPRMSC

iTrader: (7)

I would question your mechanic. An open differential is very difficult to break. Did you have any prior noises or problems with your differential before going to your mechanic?

Slow_go_400

Yes I have always had traction problems as I described above with my first and 2nd (currenlty installed diff). I through the years I slow started hearing a loud thump when taking going from Park to Drive, but from what i read this is a transmission mount (or bushings can't remember) going bad. Which is not realated to the diff problem.

Sc dRifta

if you dont race id say find a complete pumpkin from either a sc300 or sc400 or gs300 or gs400. should cost you about $250-$400 for the entire sealed pumpkin with warrenty from a reputable dismantler.

with the kaaz unit u have to reuse your old RING and PInion Gear and SIDE bearings to complete the install. there is more labor involved as well and your looking around $1200 for parts and labor.

you could probably get away with $800 for parts and labor if u use a used junkyard replacement.

if your mechanically inclined its a straight forward job simple stuff.

Sc dRifta

wrong tranny mount has everything to do with diff breaking. if u have tranny flex its gonna move your drive shaft and make it unbalanced then ur flex coupler cant compensate for that much play and your pinion gear moves up down side to side on the ring gear thus destroying the ring pinion and possible open diff carrier

Slow_go_400

Hmm that makes perfect sense. I will have the mechanic check those also.. Now if that is infact the case. Getting the diff itself would not be a good Idea since the pinon and ring gear are probably shot. I would have to get the entire LSD assembley. Since its so hard to get a used I have to buy a new one from Calrson.

So here are my choices.

92-96 SC400
8 cyl (3.92 ratio)

97-00 SC400
8 cyl (3.266 ratio)

92-96 MKIV Supra

w/o turbo; (4.27 ratio) Limited Slip ** Correct me if I'm wrong this would give me more quickness but suffer gas mileage? Also how much will my speedometer will be off if I get the 4.27?

97-98 MKIV Supra
w/o turbo; (4.08 ratio) Limited Slip * closets thing to stock? So I should get this.
w/o turbo; (4.08 ratio)
w/turbo, AT (3.769 ratio) Limited Slip

Which one do you think I should get. I'm going to run 19" wheels. I want more performance, but if I will lose gas milage how much will I lose?

jacobzking

i've got the 4.27 mated with my 5spd tranny and it tears through the gears. i can get away with skipping 2nd and 4th gears

bishoptane

some one didnt adjust the bearings correctly, and have the mechanic check out the lateral runout. something isnt lined up right.