Eric_Oz_S2

So who here has done a transaxle rebuild from their home workshop?

The reason I am asking is I am contemplating doing this, but just when I am getting encouraged to do this, I read something that says don't go there - too hard.

If you could post your experiences here, perhaps we could work out what really is possible using not-too-expensive tools.

So if you have done it:

What did you do (bearings, synchros, diff?)
How did it go?
What tools did you need?
How long did it take?
In hindsight would you do it again?
Is it still working?

Van

Does your home workshop include a press, a dial indicator on a magnetic stand, and maybe a welder and the capability to fab up some crude tools?

If so, I think you'll be OK. If not, it may not be a rewarding endeavor.

Scott at Team Harco

I had to replace the ring and pinion in my car. The car was purchased for the princely sum of $1000 and needed a bit of work. After I had gone through the timing belt, waterpump, steering rack, steering pump, suspension and brakes - I figured it was time to take it for a quick drive up to the local car wash.

As I "powered" away from the traffic light near my house, I felt a jolt and some hit and miss action in the drivetrain. After putting the car on the trailer and taking it home, I performed some basic diagnostics to determine it was internal to the transaxle. Brilliant!

After dropping the transaxle from the car, I removed the side cover to reveal several teeth missing from the pinion. I was between jobs for a short period here and was able to devote a lot of time to getting things right. The first step was to photocopy the service manual section on the transaxle (borrowed from a local repair shop). I then researched the cost of a ring and pinion set.

Luckily nothing else appeared to be damaged so it would be a moderately simple task to get the old bits out and swap in the new. The hard part would be getting the proper preload on the bearings and getting the gears to mesh properly.

Removing and installing bearings was quite straightforward with access to a good press and an oven to heat the occasional part. Setting bearing preload and gear mesh was a series of trial and measure, trial and measure exercises. I used (electrical) solder segments crushed between the bearing races and the housings to get approximations on the required shims. Install everything, torque to spec, check for shaft rotation, etc, then disassemble everything. Measure the thickness of the crushed solder and then install a shim that gives the desired preload. Reassemble with the new shims and do the trial again. At the same time - I used zinc oxide paste on the gears to check the contact pattern of the gear-mesh. Eventually, everything came together and I completed the final assembly.

The transaxle has been trouble free for about eight years and 53,000 miles. In those miles have been many track days, autocrosses and RallyCrosses.

Some of the basics:
Take your time.

Study everything available. Service manual is a must.

Arrange to have proper tools (bearing pullers, press, oven, etc.)

Take your time. There is nothing wrong with trial assemblies over and over again. if it's not perfect - take it apart and make adjustments.

After it is perfect - you'll have a great feeling of satisfaction of a job well done.

Keep asking questions along the way if you need help. There are a few others that have done this. My recollection of all the details may be hazy after all these years - but there are plenty of basics that I should have no trouble recalling.

Keep us updated on your progress. Best of luck.

Eric_Oz_S2

20t press can be bought for less than AU$300, dial indicators - $50, crude tools - no problem. Oven - might be a tight fit getting the case in the oven.

External bearing puller - yes.

Internal - no.

What type of internal puller do you need? Does it have to be the collet type?

Eric_Oz_S2

Thanks Scott.

As per my reply above - what type of internal pullers did you use to get the outer races from the case? Do the races get damaged as you remove and reinstall to get the backlash right?

tifosiman

I used Scott's crushed solder idea when I did mine. I had a total of about 25-30 hours invested in my rebuild, not including drop and install out of/into the car. If I recall correctly I had about $1000 wrapped up in the tools, shims, bearings, seals, and r&p (didn't need new synchros).

Based on the cost of used N/A transaxles out there it is certainly more feasible to just buy a used one and install it. Especially if your time is valuable. Of course most used N/A transaxles are ticking time-bombs waiting to grenade but if you don't mind dropping and installing you could buy 3-4 of them for what it costs in regards to your labour and the other tool/part expenses. I just wanted to tackle it myself and it worked out great because when I was done I had a nice, clean, rebuilt unit. Which worked out great when I finally grenaded the trans that was in the car; I just had it towed home and R&R'd the trans in a couple of hours and I was good to go. Have had the current rebuilt one in there for 3-4 years with about 6000 miles (I know, I don't drive the car much anymore right now). No problems.

I started rebuilding the last one I blew up but I'm only about halfway thru it and sorta lost interest. I need to finish it so I have another back-up.

Van

I think there's clearance to use something like this:



I don't know if you need to place the whole case in an oven... maybe just individual gears. But I may be wrong.

M758

That is the only job I have not done. However I think I will be looking to get a Gaurd LSD unit and will probably put it in one of my spare gearboxes. I have two spares and my third is in the car so I have some parts to play with.

The write up in Excellence make it seem not so bad.

Scott at Team Harco

Right - the whole case will not need to go into the oven. There are just a few cases where the service manual specifies heating parts. Generally it will to heat a bearing, for example, to press onto a shaft, etc. Cooling the other part is also a good thing, if feasible.

I don't recall needing an internal gear puller. I think external pullers and bearing separators in the press were the norm. I'll have to review the procedure in the manual to confirm.

Update with note from the service manual. I don't believe I had to deal with the races mentioned - or I did - they were not such a tight press fit. I believe I ended up using Loctite green (retaining compound) on most of the races to offer additional security.

Scott at Team Harco

The outer races can be gently nudged out with a hammer and a properly sized bearing tool (see photo above of such a kit), as I recall. No, the races do not get damaged when removing and installing to mess with the shims. Just be careful. Once you discover a method that works for removing the races, stick with it.

Eric_Oz_S2

Have you got a PDF of the article you could PM me? It would be much appreciated!

Thanks

Eric

badcoupe

I have done at least 3 over the years, if you have a good press the ability to make some fixtures lots of time and a good understanding of everything in there works it's not too bad but if you've never rebuilt anytype of of trans or setup ring and pinion before this is not a good one to learn on.

Mike C.

I did it in my garage but had access to an industrial oven and a metal lathe (I already had a press and assorted gear pullers, punches, etc.). The oven is an absolute must and the lathe allows you to make cheap copycat tools to do it as per the FSM. I enjoyed it and it has been operating fine since.

ibkevin

I was looking into this - now, maybe not..

Voith

Does anybody know what parts needs to be replaced to do the rebuild of transaxle (apart from parts that are visually worn or damaged)?

Bearings, synchro rings, what else?