Ealier this year (feb 18th 09) I destroyed my stock differential. I punched the gas in 3rd gear on the highway and a small uneven section of the road caused the tires to hop a little, I heard a strange noise from the rear end. It drove fine in a straight line, but any corners resulted in a terrible binding noise. I got it home, drove it over the pit, drained the fluid and had 2 chunks of metal on the magnet. I then decided to swap in a series 4 turbo 2 differential. Purchased one from a forum member for $250.
Pulling the differential took about 2 and a half hrs. It's pretty easy. Heres a couple pics of everything that needs disconnected for the axles to come out.
All images are thumbnails and can be enlarged.
Before:
After:
The drive shaft, has to be dropped, the ppf should be dropped, I left mine in place because my downpipe and midpipe are one piece and I didn't want to mess with that again. There are 4 large nuts holding the differential to the ppf and then 2 bolts that go through the differential bushings. Now is a good time to replace those if they are worn or you want to go with solid mounts. I made my own solid mounts awhile back that can be found in this
Thread.
My solid mounts
Once the differential case is out of the car I pulled the cover off and removed the differential. Here's a pic of the case and the stock LSD. The small spider gears were all ground off on mine.
Case:
93' stock LSD:
When the T2 differential came in I decided to take it apart and check the clutches for wear and clean everything up. Here's a pic of the T2 LSD on some blocks to measure it, the next pic is of the cover plate removed (where the ring gear mounts), and the final pics is the LSD tore down for cleaning and inspection.
T2 LSD:
Cover plate removed:
Tore down:
The FSM for the 87 T2 differential says the specs for the clutches and disks are: New - 2mm and min spec according to the FSM is 1.9mm.
THIS IS WRONG. The correct spec for new disks is 1.75 mm and min spec would probably be 1.65mm. New disks and oversized disks can be found through Mazda Motorsports or
Mazdatrix I didn't need any extra parts because The T2 differential I got was practically brand new with very little to no wear.
You can also shim the differential out to have a harder lockup. People use all different kinds of things for this with coke and beer cans being popular. The mx5 forums have very good information on doing this. It can help restore a worn differential, or provide a new differential with a harder lockup. since mine was practically new I chose not to do this.
Next I mounted the ring gear from the FD differential to the T2 differential. I don't have any pics but its straight forward. Use some loctite on the bolts.
New carrier bearings should be installed, and then put the T2 lsd in the FD case. Rarely are 2 differentials the same exact size, so you'll need to use different shims to set the backlash. I got very lucky here, and my old shims worked by swapping left to right. I doubt it will work out that nicely for me again, and very unlikely for others. The shims are rather expensive through mazda and it will usually take some trial and error to get it right. Might be best to have a differential shop do this part.
Until discovering my shims would work, I considered using several thin shims from a different kind of differential.The correct size would have to be found. This would make setting the backlash cheaper and easier. If anyone ever finds anything that would work let me know for future reference. Something like
This Is what you would look for. (without gasket) The shims have to be the right diameter though.
Pic of what I considered using:
That's pretty much it. Pinion is left alone, backlash is set. And also be sure if your spider gears were destroyed like mine to clean, clean, and clean. Those little gears get into everything. Hide around the pinion and all throughout the case. So get that stuff out of there before the new differential is in place. Put everything back in and fill with some good synthetic oil with friction modifiers for clutch style differentials. I used royal purple 75/140 if I remember correctly.
T2 differential swapped into FD
Us FC guys are lucky for not having shims though, there is adjustment on the outer race which is nice.
Hybrid Mode
