If you've ever tried to find an LSD differential for a z or zx from 70-89 you know that they're just about impossible to find. When you do find them they're usually very expensive. We now have a much more practical solution available. We're now selling an LSD conversion kit that allows you to change your open style differential to a posi or limited slip (LSD) without having to change out the carrier or touch your pinion gear. This kit works on any open style R200 from 74-89. We recommend having these units professionally installed.
We also sell a kit that will work on the R180's and one for the R160's as well. See listings.
To install this kit you have to remove the differential unit from the car, and remove the carrier assymbly from the housing. Then you have to remove the ring gear, drive out a drift pin, remove the locating pin and then take out the side and axle gears. The next step is to remove about .030 of metal off of the axle gears inside surface making sure that the surface is smooth and flat. Then clean off the gears and install the gears back in place. Then slip the LSD conversion kit into place, provided you have taken enough metal off of the gear surface for it to fit. Then you temporarily install the locating pin and measure the clearance between the LSD kit and the gear surface. Tolerances should be between .010 and .030. Once that tolerance has been achieved then put the drift pin back in, pry off the locking tabs on the LSD unit, remove the 4 dowel pins, and install the ring gear. Next you lube the gears a little and install the carrier assymbly back into the differential. Put the cover back on, and install the unit back into the car. Make sure to fill it with fluid at your convenience. Then go and drive your z for about 500 to 800 miles. That will break in your new kit. Now your car has LSD and your handling and performance has a much needed improvement.
We recommend having the gears machined by a machine shop that is capable of doing the job properly. It is possible to grind the surface down with 2 different types of hand held grinders but you have to be very careful how you do it. A big coarse wheel for taking most of the metal off and a di grinder for the final surfacing. You need to make sure that you take off enough metal but you want to keep the ground surface as flat as possible, and parallel to the back side of the gear. If you have any doubts about doing it yourself, then don't attempt it. Have it done by a professional.
You can send your carrier assymbly to us and we can do the conversion for you. Then ship your modified carrier back to you and you can put the ring gear back on, and install the carrier back in your differential unit. Labor cost to do that service is about 500.00 plus the cost of the LSD kit and possibly a rear cover gasket. Shipping is extra.
Tools needed to do this modification on the bench are: Lathe or mill with grindstone attachments or hand held grinders, a vernier caliper with a dial indicator, an inside micrometer, a long shank drift punch, 1/2" impact, torque wrench, flat feeler guages, large and medium slotted screwdriver, vise, deadblow hammer, cleaning agent, and compressed air.
We do have pics on file showing at least some of the more critical and different steps. They are available only after purchasing a kit from us. Posted pic shows the LSD unit installed in an R200 carrier after the locking tabs have been removed. This unit is ready for the ring gear and to be put back into the differential. Then after the break in period it's time to pour on the power.
These are temporarily a special order only item. Please allow an extra 7 to 10 days for delivery.
Last update 0715