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max924 · Joined: 16 Feb 2006 Posts: 19 Location: ON, CANADA

Has anyone here ever had to adjust their differential before?? I have a 5 speed (016) from an '82 in place of a 4 speed and the differential is making a loud noise as if it is not adjusted properly. The previous owner had the tranny apart and I read that if you ever take it apart you have to adjust the differential. The haynes manual is useless as it tells you to go to your nearest dealer or tranny specialist. Looking for any info on how to adjust it.

Max

Smoothie · Posted: Thu Jul 27, 2006 12:55 pm Post subject:

Waaaaay too much to type out or explain... You need a copy of the factory manual/s. + likely some special tools.
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924RACR · Posted: Thu Jul 27, 2006 10:34 pm Post subject:

Correct, you need factory manual and some tools. Not a DIY job - even I had to have someone in the know do my trans.

If you have the trans apart - no, you don't immediately need to readjust the diff. Adjusting the diff shims is only necessary if you replace bearings. Since the bearings are so robust (per the guy who built my trans), they don't necessarily need to be replaced when rebuilding - only if they're bad.

So when you rebuild one of these trans, the only obligatory replacement parts are synchros and gaskets/seals. Other than that, you must assess what parts are worn and in need of replacement. In my case, my bearings were fine, but there were some worn shift forks we had to salvage from another trans, one bought new from EBS.

Now, there are two adjustments to the diff; there's shimming the diff carrier bearings (the bearings it spins in). We had to do this in mine, because we swapped in another diff (a 951 LSD). The other adjustment is fore/aft adjustment of the pinion gear and shaft relative to the ring gear - required if you replace the bearings on that shaft or otherwise mess with that assembly (other than replacement of the synchros). We did not need to adjust this, since we did not mess with that stack and besides which, my trans builder checked it and it still felt good.

So - one thing you could do is see where the slop is that's causing the whine. It's conceivable that it's only the diff carrier bearings that are worn, in which case this should be obvious if you remove the halfshafts from the trans and can wiggle the output flanges - obvious radial play.

The other source of noise from the diff would be excessive whine resulting from the pinion gear not positioned properly relative to the ring gear - the second adjustment I cited.

While you'll need a factory manual for either - really, you need to take it to a shop who knows how to do VW/Audi trannys - the diff bearing re-shimming is far better/easier than re-shimming the pinion shaft. The former only requires normal measuring tools; the latter requires very special tools for VW/Audi/Porsche trannys. Either one is a PITA, requiring assembly/disassembly 4-5 times before complete. Yuck.

Final note - some gear whine from the diff is kinda accepted to be normal in these cars.

You need to find a shop to assess and do the work needed - whether or not you take them the trans. Cost can be expected to approach $1000, if reshimming is needed. 10 hrs is really not unrealistic, for an expert trans tech. Consider having it rebuilt outright, or installing another used one in better shape, if it really needs this.
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max924 · Joined: 16 Feb 2006 Posts: 19 Location: ON, CANADA

well, I have a fully equipped machine shop and I have even done rebuilds on automatic trannies, so I think it could be possible for me to do it other than these specialty tools. Could I fabricate these tools? The noise is more than normal and I would just like to make it quieter as I am trying to sell the car. Where can I get the FSM's, there probably not on the internet and my local Porsche dealership (as in 3 hrs away) has never been very nice to me.

Thanks

Max

Ozzie · Posted: Fri Jul 28, 2006 9:11 am Post subject:

They do come up on Ebay from time to time.
4 books in total.
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gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

If you are selling the car anyway, unless the tranny is broken it would be hard to justify the expense of a tranny rebuild.

The cost is going to be more than the gain in selling price. Heck, the cost of a good tranny rebuild could exceed the selling value of the car.

Sell it the way it is...

Tell the Buyer that it may have a problem, give him a fair price, and let it go.