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Limited slip diff.

Posted: Mon Aug 17, 2009 6:27 am
by RWK
I have an opportunity to get a LSD for my thing (IRS) its from a thing I was told, OEM markings on it , any one know or can advise about one? It has some numbers on it and VW but could not fine LSD number 001-517-025. Are any parts availible ?clutch discs? Do they wear?
Thanks
RK

Posted: Mon Aug 17, 2009 6:50 am
by Glenn
Wait for Bruce Tweedle to post... he's the ZF LSD expert.

Posted: Tue Aug 25, 2009 5:03 pm
by Kubelmann
Although I do had the ZD LSD installed on Herr Kubelmann, I concur that a Post from our resident expert (Bruce) on VW trans should post prior to making nay decision. It is a great addition to any off road car....

Posted: Sat Sep 19, 2009 10:23 am
by Bruce2
The VW part number (001-517-025) does not appear on the diff. The only part numbers you will find are the individual ZF part numbers of some components, then the ZF part number of the complete diff.

The commonly accepted myth is that the discs wear out. I've been inside over 100 IRS ZF diffs and I haven't seen one single worn out disc yet.

There are 2 other ways for damage to occur to the discs.

The inner splines of the inner discs sometimes get beat up resulting in play between the discs and the side gears. I don't have a theory of how this happens.

If you don't change the gear oil, the lubricating properties degrade with age and use. Eventually you will see a lubrication failure resulting in the discs seizing together. Some may call this wear, I don't. Change your gear oil and you won't see this problem. I have noticed that the gear oil in my gearbox degrades within 10k miles such that the diff doesn't work the same as with new oil.

Post a pic of the diff you've found.

Posted: Sat Sep 19, 2009 8:15 pm
by Kubelmann
Frequent fluid change is the best medicine for any machine. I run high end fluids and still change them often.

Posted: Wed Sep 23, 2009 9:11 pm
by RWK
Yes will try to post a pic, got some VW info/lit. off samba regarding special oil , whats up with that, is that like an additive used with gear oil like in modern lsd like my Ford truck? Any dissasembly tricks /cautions/ dont do's. Would like to clean it up make sure nothing in side,dirt,ect.
RWK

Posted: Thu Sep 24, 2009 9:35 pm
by Bruce2
Get your LSD additive from Chevrolet.
You must use the additive unless the gear oil you are using specifically says not to use it. If your oil says compatible with LSDs or something like that, you need the additive. Then you need to change your gear oil every 10k miles.

There's nothing to cause problems when you take it apart. Just pay attention to the order of the parts. Take pics as you pull it apart. You are right, it's going to be nasty inside.

Re: Limited slip diff.

Posted: Fri Dec 18, 2009 7:07 am
by DannyK
Did all Things come with Limited Slip ?

Re: Limited slip diff.

Posted: Mon Dec 21, 2009 2:36 pm
by fusername
no, only some did. from what I can gather two of the tranny codes (there may be more) AV and AW. AW means LSD, AV is normal diff.

Re: Limited slip diff.

Posted: Sun Dec 27, 2009 4:30 pm
by Bruce2
The only Things with a LSD are ones that were ordered that way from the factory. If you think you'll check a few Type 181 gearboxes for one, don't hold your breath. VWoA did not offer the option, so none of the cars they sold had it.

Re: Limited slip diff.

Posted: Mon Dec 28, 2009 1:55 pm
by fusername
well thats dissapointing. Does this mean mostly only the ones that were originally sold to govntmt entities had em or what? There goes one more thing on my list of junkyard treasures.

Re: Limited slip diff.

Posted: Sat Jan 02, 2010 2:46 pm
by Bruce2
Some were installed in vehicles for military use in Europe. Or in other countries VW sold the option to the public.

Re: Limited slip diff.

Posted: Mon Jan 18, 2010 11:53 am
by Steve181
Hi,

to the best of my knowledge, LSD was installed mostly on cars issued to the Bundesgrenzschutz (border guards) and the forrestry. Am away from my books at the moment so cannot confirm numbers, but am not aware of any going to the military - apart possibly from some early units (with the reduction hubs - which gave additional ground clearance and gearing).

Changed the LSD on my VW82 last year - works like a dream now, and can confirm the offroad improvement of such an addition.

Perhaps others can provide more detail for the 181.

Cheers,

Steve181
Kidderminster, UK

Re: Limited slip diff.

Posted: Mon Jan 18, 2010 12:20 pm
by Kubelmann
When we part by part constructed the Trans for Herr K. We had stock 1973 AV Thing transaxle. This unit had no rear issues other than being driven for 28 years (at the time) A complete list of internal parts was created. We purchased all new OE German replacement internal parts direct from VW. Weddle entered the picture with close ratio, electron beam welded 3rd and 4th gears. steel shift fingers and a load of other performance parts. Lastly, I was able to obtain a LSD Quaffe rear diff. It came of my pals Pike Peak Hill Climb open wheeler that had shove a piston through the engine case on the first practice run of the season. The season over, cash flow low, I bought the diff as new (with less than 20 miles on it) for $300. Upon trying to install the diff we found far too much side play and built a set of shims to have every thing just so. Now, ten years later, that trans can shift to any gear any time in any terrain. Mated with its 110 hp 1915 motor. They work very well together. I suspect that the wear Bruce mentioned could result from not the correct side clearances as we cured with the specially machined side shims. With the LSD I can cover my front headlights and windshield with a pair of solid rear tire rooster tails. No lack of traction on that car.