ATC529R

I have a 84 GSL rear end. Pretty sure thats the one, it's the one with 3.909 final drive and I have a 1980 (3.909 as well) original rear end I'll probably swap the spider gears from. My questions are can anyone point me to a source for the LSD clutches and/or the bearings that go on the gears that go on the axles. sorry, not sure I know the name of those, but the bearings that are there when you remove the main caps, as I took the chunk out of the 1980 rear end and am in the process of taking that apart.

The 84 in the car has chatter and a pretty decent clicking when cornering, so it's time to go in there. Any help, advice, tolerances, torque specs etc would be appreciated.

Thanks

ATC529R

edit, looks like Mazdatrix has a lot of parts, bearings, shins, spacers, clutches etc..... damn will add up to a lot if I start replacing all that! Let me know the main things to "look" for as far as issues.

I guess my first course of action is to get the chunk out of the rear end in the car and inspect and start checking clearances etc. ugh. I hate pulling it apart and then waiting for parts while it's in the garage on jacks. I just finished the car, but really don't want to cause any more or major damage by continuing to drive it and cringing on every corner. ah well.

oh, and how do I know if the LSD disc's need replacing?

j9fd3s

iTrader: (3)

you measure them and look for scoring/burns other damage.

its worth mentioning that the break in for an LSD is just to drive slowly in a figure 8 for a bit, and you might want to try that. before you pull it apart

GSLSEforme

Side gears(spiders) from 1980 diff will not work in 84 diff as they are early small axle.

ATC529R

the axles are mosler axles.

ATC529R

LOL on the figure 8's. Pretty sure I tore this thing up doing donuts before it was broke in. Had a bad day and decided to blow off steam and went to a culdasac and let it rip.........it was fine before that!! figure 8's is a def no-no at this point.

thanks for the scoring tip, will watch some LSD videos before I dig in and check the FSM for spec's.

GSLSEforme

If axles are in 1980 diff they are small bearing axles. 1984 axles are large bearing,the two are not interchangeable,nor are side gears from each.

GSLSEforme

Moser

ATC529R

The axles are mosers. I sent them an 84 axle to them and they replicated them. Now, if the inner diameter and/or spline count is different than the 1980 and won't fit those side gears.......well, you just ruined my plans.

I hope you're wrong, but given your screen name you're probably right, but I could have sworn they were identical except for the large bearing.

GSLSEforme

Well,i'm not about ruining anyone's plans... The Moser axle will fit a big bearing rear axle,that's not a problem. The 80 differential is small bearing and nothing in that diff will work in later axle except ring and pinion. The carrier and all parts integral to it including spider gears only works with small bearing axles. Think about it,the axle goes into carrier thru splines inside the spider gear. A larger axle needs a larger id spider gear to go into...

GSLSEforme

Take apart the differential in the car and put a list together of parts actually needed.

ATC529R

Well, you are definitely right about only the ring and pinion being the only transferable parts.

I have disassembled the rear end. All the clutch plates look good and measure in the 1.99, 1.98 range with a 2.0 recommended and 1.9 minimum. They look good and the thrush washers are 1.55 with a 1.6mm factory and 1.4 minimum, so those look good. What is concerning is the conical springs.which both measure about 1.68 with considerable glazing or whatever you call it where a lot of the friction are is worn away. I’d say 70-80% on one and 60-70% of the friction area is almost smooth.

obviously these will be changed but there are no specs on them in the FSM.

I’m thinking change these, tighten outer screws on the bearing collars etc. and make sure all is within specs as to backlash with a micrometer. The ring pinion, spider gears etc have no noticeable/abnormal where from visual inspection.

I’d like your opinion on those conical spacers please.

could they be causing the clicking/binding noise I hear?

ATC529R

From Mazdatrix on a couple things.

1. lsd additive

If you get a “chatter” from the rear axle when starting from a stop, and turning at the same time, you need to add this additive to your rear end oil. This is due to the clutches in the differential locking and un-locking. The Limited Slip Additive assists with the applying and releasing of the clutch plates. One container/part number needed per rear end oil change.

people told me this, but I hardly thought that the loud clicking was just chatter. Hmmmmm.

and then this from Mazdatrix about a kaz coated differential

2. WPC is a coating applied to the LSD to allow for less noise when turning. If you will be
using this LSD in a street car and would prefer not be noticed every time you turn, it is
recommended that you get WPC coating. However, if you do not mind a loud “banging” noise
when turning, WPC coating is not needed.

keep in mind I have 245/50/16 tires and those moser axles don’t have the ring on them that goes to the disc combined with a v8 that may just have a little too much torque than what this LSD was designed for.

Add those up and the chatter/clicking on corners is something I’ll have to live with or swap to a different rear end once/if I toast this one????


kinda sucks cause I figured what the heck, I have an extra ring and pinion if I fry this one.........but that clicking........grrrrrrrrr!

If nothing else I have piece of mind knowing it’s not any of the gears and I can lay into it.😅

DriveFast7

iTrader: (1)

You do need to run Limited Slip Additive in a Mazda clutch diff or it'll make a racket.

No idea about Kaaz, never owned one.

ATC529R

So, update. Went through the rear end. The pinion needed snugging up a hair, changed outer conical plates and tightened up outer adjusters. Went through it to make sure it’s in specs and it needed a turn here and there. It had seen some track time and I think it was set up a little sloppy for a 12A. No more slop when letting off, no more clicking, hooks up hard.

sometimes you just gotta go through it I guess, but night and day difference.