[watermouse]

Can someone recommend a good diff service centre in Adelaide?

I have put together my front 5.12 steel third/centre but it needs going over with a torque wrench and the preloads set.

What could I expect to pay for this kind of service?

[atari4x4]

boss differentials in lonsdale

how did you go setting the pinion depth when swapping the 5.12 R&P into the steel 3rd or does all the set up still need to be done?

[watermouse]

Thanks Atari.
It all needs to be done, but it has all bolted up surprisingly nicely. There is no oil in any of the bearings so it is slightly stiff but smooth. I have the service manual but it looks to be a pretty involved task. Do you know how much that might cost?

[atari4x4]

have a chat to scottie as he recently had a ratio change done, pretty sure he went to boss.

[watermouse]

wow, first quote $500

[atari4x4]

do you think that's cheap or expensive?

it's an intensive job & really is a bit of a black art...

[Marko_SJ]

I had a diff done for 300, I felt that was a good price.

[atari4x4]

was it a complete ratio change, new crush tube etc etc?

[watermouse]

atari4x4 wrote:

do you think that's cheap or expensive?

seems expensive (on my current income). really depends if other people quote similarly. Yet to try Boss.

[Marko_SJ]

atari4x4 wrote:

was it a complete ratio change, new crush tube etc etc?

Ratio remained the same, it was a complete overhaul though.

New pinion seal, bearings, crush tube and carrier bearings.

[jdk81]

Its possible you haven't helped them at all.
What was the number stamped on the pinion, did you measure the shim?
Which shim did you use? Shim from new pinion, or old pinion?
As the shim the pinion came with is a good starting point, its possible the cradle machining is different and you will need a different shim.

If the pinion shim isn't correct, its pull it apart, and try a different shim.

Did you set it all up and then use gear paste to inspect the pinion depth?

If you did all that correctly, you can do the rest easily.
A torque wrench is $80.

Or else they will tear it down and start again.

[watermouse]

Thanks jdk. I would have expected the pros to pull it down again anyway. Its not that hard to disassemble. Only took me 5 minutes.

I pulled it apart again just before I left the workshop. Both the 4.3 and 5.12 pinions have 94.00mm stamped/etched into them, which is also the figure that gets mentioned in the manual.
A quick check with a ruler to the side bearing housing split (assumed centre plane/axle center) shows that it is very close (93mm) but without the nut on the end of the pinion pulling it in.
Both crush tubes are exactly the same length so it is highly possible the 5.12 pinion was in the right spot (by chance or good Suzuki engineering?) It seems I just need to set the bearing preload correctly.
My homework tonight is to go through the service manual and nut out the assembly process more thoroughly. Before today I really had no clue but it is starting to make a lot more sense.
I will post up some pics tomorrow.

[watermouse]

Also, neither pinion appeared to have existing shims

[Polar_Bear]

Ive used Dinos Diffs in Brompton. Did an awesome job and was one of the cheapest i found.

[droverdave]

For what its worth it cost me $110 for a new pinion seal, new crush washer, set the pinion depth (the shims you speak of) and do up the front nut to set the preload on the pinion bearings.

What you are asking them to do is all of this, plus set the sideways movement of the centre and ring gear (which sets the contact position as well as backlash in conjunction with the pinion depth). $500 seems a bit high, i would have expected $250-$350.

Also note the shims are only put in if required, its possible that the pinion depth is correct without a shim.

[watermouse]

Thanks Polar Bear and Droverdave, those prices sound much more reasonable. I will check them out too.

However in the meantime I am having a bit of fun with this. It might all go to the pros yet but this is what I have done so far...

This morning I swapped the inner pinion bearings because the one on the 4.3 pinion looks like new. (I don't think this diff saw any work, seals are mint. no seal wear mark on drive plate either.). Then I noticed there were shims on both pinions.
The 4.3 had a 1.15mm shim, the 5.12 had a 1.21mm shim.


I fitted the thinner shim and the better bearing to the 5.12 pinion and pressed it back together.

Once back in the housing and tightened so there was no play in in the pinion and with moderate drag to rotate I measured from the side bearing split to the inner pinion bearing center face.
The measurement with verniers was 95.48mm. (measured a million times)



So 95.48mm - 1.15mm = 94.33mm. This distance is still too large by 0.33mm. The pinion needs to move towards the axle in by this amount.
The other shim is 0.06mm thicker but that will only get me to 94.27mm

The next step is to get some/make some shims but this could take a few days.

Once this is done setting the crown wheel engagement and backlash I think will be easier because it is all adjustable with everything bolted together.
At the end of the day if a feel like I am miles out then it will go to the shop. Time is on my side with this little side project.

This may end up as a How To thread but we will see. Any input appreciated.

[droverdave]

You got some bearing blue to check the contact patch?

[watermouse]

yes, theres some kicking around somewhere.

[atari4x4]

what mob gave you the $500 quote, was it SA trans & diff in the city?

just don't do this to it, incorrect set up was the cause.

[watermouse]

precision differential and gearbox, port road. Their workshop is pretty tidy, I have no doubt they would do a decent job

Diffs can really only go crunch one way. That looks like the inside of the Jimny rear diff when it blew at 240,000. But that one had never been out of the car for a service. The gears were pretty thin.

What were you doing when that blew?

[atari4x4]

Ask klutched... It's his diff that they swapped the ratios on.

Precision would be the most expensive place in Adelaide, SA diff & trans next, boss & Dino would be significantly cheaper.

[watermouse]

Progress.
I chatted with a couple of old brothers down the road who service and maintain track cars for a handful of clients. I was just seeking some advice but I came away with a handful of useful tools and a 0.3mm shim.
And an offer to redo it if I get stuck.
Top blokes. There is some serious automotive gold in their workshop.

The pinion is now sitting pretty with the extra shim and the centre is back in for backlash adjustment and side bearing preloading. This is the setup before I went home. It needs some more tweaking to get the lash within 0.13mm and 0.18mm, (checked in 4 places). Currently it is 0.10mm so I need to back it off a bit but I had to leave. (and I was just getting into the swing of it)



The contact patch check will be the sign to see if I have got it all right. That will happen after the weekend camping trip.

[watermouse]

I managed to find some time to get some more work done on the diff.
First up was getting the composite preload correct. This is the from the combined drag in all the bearings. I did this check about 4 times and had to tighten the side bearings each time to get the preload correct, checking the backlash doesn't change after each tightening. The spec is between 6 and 7Lbs of pull at the drive flange. No tight or rough spots in the rotation either. So all looking good so far.

Everything is now torqued up to spec.
Now for the contact marking


Then rotating the drive flange with one hand while applying some drag on the crown wheel with the other to load up carrier. I go back and forth few winds each way to get marks on both side of the teeth on the crown wheel.
This is what I get on the drive/power side for forward rotation.

It took me a little while to work out what I was looking at here because it is a little bit different to the diagram in the manual. It looks as if the pinion could come up a bit to move the contact patch further into the tooth. But looking at the original wear on the crown wheel teeth it looks about the same. What is more important, I am told, is that the pinion does not rub in the edge of the tooth. So I am pretty happy I am well inside the ball park, probably somewhere near silly-mid-on.
I also got bit confused to start with because the manual says the convex side of the tooth is the drive/power side and the concave side is the coast/reverse side. I quadruple checked under the car to see which way the diff mounts and rotates and it definitely is a typo. The concave is the drive side for the front diff (it is opposite for the rear diff, cut and pasted from rear diff setup instructions me thinks)

I did the same for the rear too but first I checked the lash and preload. The rear 3rd I have is much more used looking (naturally). It has pretty loose preload but with good wear and pattern.I took 0.05mm of lash out of it.
I have dropped both the front and the rear diffs into the race car guys down the road to get them to check my work and their initial response was that I was very close, maybe close enough but they had a diff guru dropping in today and will get him to evaluate as well.
One thing to consider is that both of these diffs are second hand so checking contact patch shape and position is always going be affected by how they have been set up originally and how they have worn in with use.