alrite guys, i just purchased an LSD 1984 3rd member and i wanted to make sure that it works correctly. i put this diff into my 84 GS. The 3rd member looks like its been sittin for quite awhile and developed minor rust on the outside but i put it in my car anyways hoping that it will work. does anyone have any suggestions on how i can check whether the LSD is functioning correctly??? it drives fine but i sometimes i hear a random clunk. the noise is really really really light clunk and not often at all, very random. not mutiple clunks either... it kinda sounds like something disengaging. and also, i had to swap the companion flange because the guy i bought it from was planning on putting on his rx2 which connected to a different driveshaft and i heard i'm suppose to reset the backlash. i just tried doing this by marking a line on the flange and nut and just over tighting it to that point or a little tighter. but anyways i jacked the car up today and i lifted up the rear rolled the tires i hear nothing... smoooth.. but when i stop one tire and roll the other one. how lose should it be?? i dunno... i just want to find out whether i purchased a good LSD or not?

 

oh yeah, i forgot to mention that when i have both tires lifted and i roll them they roll the same direction. as in, if the car were to be driving forward the other tire looks like its driving foward as well. i thought one tire rolls one way and the other tires rolls the opposite, only when its lifted??? and when i stop one tire and roll the other one its pretty rough.. sorry guys forgot to mention that

 

I have a good set if you need one

 

standard diff, one tire will pin forward while other spins backward. LSD, both tires will spin forward, or both will spin backward. Now, that only tells you that you have an LSD; can't really tell if its a 'good' LSD that way, just gotta drive it and see what it feels like

 

With the rearend in the air and one tire stopped, the harder it is to turn the other wheel the better your LSD. If it spins pretty easy, time to hit wacky up for his.

 

thanks guys i appreciate the help... now that i know that the LSD somewhat works, i think i found out what the clunk noise is. there's a little play on the drive shaft... just slightly very little... is this good or bad??? when i move the axles one way and the other.... there's a slight play very little as well... AND i started to notice that when i make a u-turn or a 90 degree turn the rear kinda jitters real quick. what might that be??? anyone have this problem before or know these symptoms

 

It is probably the U-Joint.

 

i didn't have this noise on my NON-LSD diff. the car ran perfectly fine... the car runs fine with the LSD but the noise is still random and chatters on cornering. today i did a fatty burnout and the car launches fine. i actually have power to both wheels not just one!!!! the noise didn't get louder or anything. still real light and random

 

The harder it is to spin just one tire when the rear is in the air,the tighter the LSD is and the better its condition.Our LSD units are multiplate and dont tend to ratchet or chatter much unless you forget to use LSD gear oil or you purposely set them up tight.I believe the factory break-away force is supposed to be around 100lbs.....dont know for sure.

I just rebuilt my entire rearend and LSD to near original specs and I can turn one tire by hand,but I have to bear down pretty hard on it.Here are links to my rebuild threads should you need to tear into your unit.Also,pulling the companion flange and re-installing without a full teardown is scetchy and you can almost never get the pinion preload back where its supposed to be.I elaborate on that about 1/2 way through the diff rebuild thread..........

https://www.rx7club.com/1st-generation-specific-1979-1985-18/differential-rebuild-tutorial-711712/ ......diff rebuild

https://www.rx7club.com/1st-generation-specific-1979-1985-18/gsl-se-lsd-teardown-pics-drivetrain-tutorials-coming-soon-707958/ ......LSD rebuild

 

Sounds like the clutches in the LSD. Did you add the correct gear lube for limited slip differentials? Did you add the special friction modifier such as Sta-Lube Equa-Torque? Should be available at most parts stores and at Chrysler under #4318060, Ford #M2C118-A, GM #1052358.

 

the additives i used was lucas stabilizer and royal purple 75w-90

 

the play in your axle might mean its time to replace your axle bearings. When you do that make sure the machinist knows how too, usually requires cutting off the retaining collar, and bearing, and replacing the small retaining collar(the thin one on the outside of the bearing), replacing the wheel bearing, and the retaining collar. Reputable racers recommend you request the machinist to use Loc-tite when they press the bearings on to help prevent the bearing from traveling again.

Please get some LSD additive for your rear diff, it will really help it last longer, and their is a noticable difference when used. It only takes a bit.

*how many miles were on the used diff?

 

i'm not too sure how many miles were on it. i didn't have any play or any noise when i had my GS 3rd member on it. wouldn't this occur regardless on the type of rearend?? before with my GS DIFF it ran fine and now with the GSL DIFF i started to notice the play and noise

 

sorry guys i was at my buddys house and i accidently used his screenname