How to swap a MA61 diff into your MX73?

[RA35GT]

G'Day all,

I've recently did this swap in my cressida and wrote a step by step guide on how to do the swap (including some pics).

The guide is located a few posts below now.

PM me if there are errors or if there is something you want to add etc etc.

I hope someone finds it useful :)

Rudi

[CrUZida]

Couple of points.

Put oil in BEFORE you reinstall the new diff. Its at least eleventy billion times easier.
And make sure you remove the fill plug BEFORE the drain plug. As if you remove the drain plug first, and then find out you can't get the fill plug off, you are stuffed.

MX73's from 1986 onwards have the diff spaced down by ~4mm (different top mount, and holes in subframe have washers in-situ).
So you will need to swap that top mount over.

[RA35GT]

I had this hosted elsewhere but figured I would put it in here. I did this again recently so have added some extra photos also.


Disclaimer: I take no responsibility for the work that you do on your car, or any damage caused while following this guide.

Tools you will need:

1/2" Drive Socket Set (with breaker bar) (14mm, 17mm, 19mm sockets)
Spanners (12mm x 2, 14mm, 17mm, 19mm)
Pliers
Zip Ties
Jacks
Jack Stands



Parts you will need from Toyota

Top Diff Nut - 90179-12045 x 2 - AUS$5.05 ea.
Diff drain and filler plug washers - 12157-10010 x 2 - AUS$1.30 ea



Step One: Raise the rear of the car.

Chock the front wheels (behind and in front of the wheel to be safe)
Make sure the handbrake is on tight
Get jack stands ready on either side of vehicle
Jack vehicle up, I jacked it up from the rear crossmember, make sure you jack it up on a flat surface.
Place jack stands into a position that will leave the car as level as possible, this will make putting the new diff in much easier


Step Two: Undo the Rear Axles

Undo the four 14mm nuts that hold each axle to the diff, Easily done with the breaker bar and 14mm socket. (See Photo for reference).
Pull the axle away from the diff by sliding it off the studs and secure them with zipties or similar out of the way (if you swing them forward you can zip tie them to the suspension arms)

http://members.reynolds.net.au/~poulose/Axle_Nuts_Studs.jpg

Step Three: Undo the Tailshaft

Take the handbrake off and put the gearbox into neutral so you can turn the tailshaft around.
Undo the four 12mm nuts and bolts holding the tailshaft onto the diff, you will need two 12mm spanners, these shouldn't be too tight. (See Photo for reference)
Put the handbrake back on and the gearbox back into gear (or park)
The tailshaft may be a little difficult to pull off, this just means its stuck on the spigot. Use a piece of wood and a hammer to persuade it off

http://members.reynolds.net.au/~poulose/tailshaft.jpg

Step Four: Undo the front diff bolts.

Undo the eight 17mm bolts holding the front of the diff to the rear crossmember, you will need the breaker bar and 17mm socket for these as they are fairly tight (See Photo for Reference)
You may want to put a jack under the front of the diff to make it easier to get the bolts out.
Note: The order doesn't matter, the numbers in the photo are only to show the location of them all

http://members.reynolds.net.au/~poulose/Diff_Bolts.jpg

Step Five: Undo the top diff bolts.

Firstly place a jack under the back of the diff so you will be able to lower it down slowly.
Undo the two nuts on the back, you will only need the 19mm socket and breaker bar as the head of the bolt is attached to a tag that is bent up around the top diff support. (See Photo for reference)
Once both the nuts are undone adjust the jack until you can pull the bolts out.
You will need a mate to help you lower the jacks and to make sure the diff doesn't fall off the jack
You have to drop the diff out fairly square to get the rear mount out at the top so put another jack under the front of the diff
Lower the jacks carefully and evenly, if at any point the diff doesn't want to drop any further make sure the rear jack is say ~5mm under the diff and then use a hammer handle etc. to lever the top mount out. Don't use too much force as you don't want the diff crashing into the jack and potentially knocking it over.

http://members.reynolds.net.au/~poulose/Diff_top_bolts.jpg
http://members.reynolds.net.au/~poulose/Diff_top_nuts.jpg

Step Six: Compare the MX73 diff with the MA61 diff....In particular the top bracket that bolts to the diffs. (See picture for reference)

If your lucky they will be the same and you can continue to Step Seven, otherwise you will need to swap the top brackets over on the diff...See note to check if this applies to your year MX73
You will need the 19mm socket and the breaker bar. Undo both bolts on the two diffs. (See picture for reference)
Swap the bracket from the MX73 diff onto the MA61 diff and reinstall the bolts. Torque the bolts to 61ft-lb (or 83Nm).




Pre 1986 MX73's have the same top mount as the MA61 thus you don't need to swap them over
1986 onwards MX73's will need to have the top mount swapped over
1986 onwards MX73's are spaced downwards 4mm and the holes in the subframe have washers in situ


http://members.reynolds.net.au/~poulose/MA61vsMX73.jpg
http://members.reynolds.net.au/~poulose/Diff_Top_Crossmember_Bolts.jpg


Note differences in height of mounts.
http://img641.imageshack.us/img641/8808/topmountcomparison.jpg

Note spacers in diff mount on car. (1986 MX73)
http://img203.imageshack.us/img203/5617/spacersindiffmount.jpg

Note no spacers in diff mount on car (1984 MX73)
http://img687.imageshack.us/img687/125/nospacersindiffmount.jpg

[RA35GT]

Step Ten: Change the Oil - This has been moved up in the sequence as while its possible to do this at the end it is heaps easier to do it now

Before draining the old oil make sure you can undo the filler plug first, a 24mm socket and ratchet should do it
Have a drain pan ready and undo the drain plug, using the 24mm socket and ratchet
Let the oil drain for a few minutes
Reinstall the drain plug with a new washer *See Note below, Torque the plug to 36 ft-lb (or 49 Nm)
Take the filler plug out, if you haven't done so already
Fill it up with LSD oil, specs are given in the picture below
You don't have to use Toyota Oil, some people on the forum have had success with Penrite Limslip
The manual states it takes about 1.2L, the oil should end up just under the level of the filler plug, as in the picture below
Reinstall the filler plug with a new washer, Torque the plug to 30 ft-lb (or 40 Nm)




Toyota Part # 12157-10010 AUS$1.30 ea


http://members.reynolds.net.au/~poulose/Diff_Level_From_Manual.gif

Step Seven: Installing the MA61 Diff

Although not absolutely necessary its a good idea to run a tap down all the bolt holes and run a die nut down the bolts, this will ensure there are no surprises once its all in.
You will need a mate to help you again. Make sure you have the two top bolts (the ones with the tag on them) nearby.
Lift the diff into position, either using the jack or by hand, some jiggling is required to get it to sit right so the jack is the preferred option.
Once the diff is sitting properly in the top mount you can put the top bolts in. (Remember they are put in from the front)
Put the nuts on so the bolts can't slide out (Do them by hand only at this stage) NOTE: These nuts are listed in the manual as a Non-Reusable Part, I don't know if you can still get them from Toyota.*See note below
Now depending on how level the car is you should be able to get the front diff bolts in, get them all started before tightening any
If you are having trouble with holes not lining up etc. try jacking up one side of the car (use the Toyota jack under the jacking point for example)
Once you have got all the bolts started you can do them all up with a ratchet, once they are all done up firmly with the ratchet you can torque the bolts down.
The front diff bolts and the top nuts are torqued to 61 ft-lb (or 83 Nm)




These nuts are available from Toyota, Toyota Part # 90179-12045 AUS$5.05 ea



Step Eight: Reinstall the tailshaft

Install all the bolts, nuts and washers (I used new spring washers).
Tighten the bolts evenly (tighten one and then tighten the diagonally opposite bolt)...You should be able to see if its seated properly
These should then be torqued to 31 ft-lb (or 42Nm), but I couldn't get my torque wrench into them so had to guesstimate, (If you had a crows foot you could possibly torque them)


Step Nine: Reinstall the rear driveshafts

Cut the zip ties and position the driveshaft over the studs, you may have to rotate the diff until the driveshafts slide down into place
Install the four nuts and washers (I used new spring washers)
Tighten the nuts evenly, same as for the tailshaft previously.
Then torque the nuts to 51 ft-lb (or 69 Nm)
When it comes time to line up the other driveshaft, you may have to rotate the diff once again.
Due to being LSD make sure to jack the wheels of the ground!
Ensure you put the handbrake down and the gearbox into neutral before rotating the diff
Re-apply the handbrake and put the gearbox back in gear (or park)
Proceed as before, install all nuts and washers, tighten them down evenly and torque them to 51 ft-lb (or 69 Nm)


Step Eleven: Go for a drive

Make sure there are no rattles, vibrations, oil leaks etc
Note: Your speedo may be out if the ratios of the diffs are different