My rear on my 85 GSL-SE is whining pretty bad now. When I am decelerating it is especially noticable. Its a turbo car and had its fair share of beatings at the drag strip so I am not surprised about the noise. I just want to know if rebuilding it will eliminate the noises from behind. In your experiaence, how much power can these stock diffs take?

danny C

 

they're very strong diffs. replace the gears you your good to go. preload the greag properley otherwise your noise will come back to haunt you. i've also swaped out 5.0 mustang read ends into 1st gens. gas tank requires some adjustments.

 

preload the wha?

 

wait, replace what gears? ring and pinion? Mazdatrix want $500 for them. What is the usual known failure, bearings? broken gears? Whats making noise, I would think it is a bearing.

I dont know if I am ready for the big swap to a 9" ford rear because I still like to drive the car on the street. Although I would love it for the track;then I could mount some slicks on the car and really launch it.

 

No one has any input on rebuilding a rear .. oh well. I guess I will just figure it out myself.

 

Usually due to a worn ring and pinion gear. Easy to check by following the manual.
Your better off if it is worn out to buy a good used diff for far less. rx7doctor

 

i have the whining noise as well, but not as much.

i wonder if there's a rebuild kit or someone to take the FB LSD to and get it done?

 

There are several places where you can get it rebuilt in LA but for the price, you're better off getting a used one. I know someone with a couple of GSL-SE 3rd member.

 

yo mama?

 

ITs probaly the pinion bearings. Make sure to get a new crushsleeve, and properly set your pinion pre-load. If you dont know what that means, than take to a shop.

 

The noise is coming from the bearings, not the diff. The diff only makes noise around corners, and even then most of that is tire shudder.

 

I already yanked my differential out to look at it. I haven't disassembled anything yet. I am reading the factory service manual as we speak.

It looks like I will change the pinion bearings(front and rear as per the FSM). I won't even disassemble the LSD, I will just inspect the exterior bearings and replace as necessary. I have to check the pinion height and adjust the backlash as per the FSM with help from an 'experienced' friend. ~$65 in MazdaComp parts:

0305-27-171 - collapsible spacer
0755-27-210 - pinion bearing front
M005-27-165 - oil seal
0223-27-030 - lock nut
0221-27-210 - pinion bearing rear

Sounds like a plan.

I would rather do this than spend money on a 20 year old differential. Unless it is was really cheap.

Thanks for all your inputs
danC

 

I changed the pinion bearings and their races. I also swapped out the old pinion spacer for a new one of the same thickness(3.11mm). Ring and pinion, LSD, and all else remains the same (stock). Do I need to recheck the pinion depth?

I asked 2 local shops how much they would charge setup my rear and I was told $240 by one and $350 by the other! D-A-M-N!

So now I am ready to start adjusting the backlash myself but I am missing a few tools that the FSM calls out. I am willing to spend some money but if I buy everything that the FSM mentions I will surely be (even more) broke. I am not sure which measurements are really critical and which ones can be worked around. For instance:

A differential wrench? Can I turn the adjusters by hand, with a screwdriver?

Backlash - I do not have a dial indicator, nor do I have any way to mount it rigidly to the carrier.

differential bearing preload - Do I really need to measure with an 7~8 inch micrometer to measure the distance between both pilot sections on bearing caps?

preload drag- how important is it because I dont have a torque wrench that goes that low.

red led - Is there a substitute or can I get that locally?

For anyone who has done this can you help me out with some tips.

thx

 

wow. no one has any tips? that's disappointing.