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Date:         Fri, 13 Oct 1995 16:11:45 -0400
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         drew@interport.net (Derek Drew)
Subject:      Syncro Front Drive (MUST read for 4x4 owners!; Big TRANS post)

This message is a response to skidooer's request for information about ADM front final drive transmission pieces apparently available thru Wheedle for the Syncro Vanagon.

Firstly, the possible availability of ADM front final drives in North America is stunning.

>From my reading of a special 4x4 trans manual by VW it appears that ADM refrers to front final drives with a final drive ratio of 38:7=5.43. This is a special gear ratio. All USA syncros have ratio front and rear of 4.86 (regardless of the mistake in Bentley that says otherwise!!!)

I cannot understand why Wheedle is offering to supply 5.43 diffs when there are no 5.43 gear sets running around this country. It may be that Wheedle got fooled by the mistake in the Bentley book and is offering ADMs thinking that we need this ratio. Or perhaps Wheedle has access to some ADMs that have been altered to 4.86 so then they are OK for you to buy.

On the other hand, a 5.43 gear ratio transmission such as this is an excellent proposition as it allows you to mount taller tires in a syncro and not loose power and acceleration, and thus you get more ground clearance. I would die for this, personally.

The rub is that there are no rear transmissions with 5.43 gear ratio in North America. This is important because the final drive ratio of the front diff and rear trans unit must match.

You can adapt a regular North American transmission to 5.43 by ordering the 5.43 gears themselves (ring and pinion) and have these installed by someone. But you would pay a lot for the parts plus about 10 to 15 hours labor by a skilled transmission mechanic used to fixing syncro trannys, (plus the cost to remove and installl the tranny.) Since there are not such mechanics around (except possibly Wheedle or others I don't know about) the job isn't likely to be done right and so your 5.43 rear is likely to break down after a year of use.

I know a skilled mechanic in Queens, New York who fixed his own 4x4 tranny last summer. But by February he was on the phone to me looking for another unit as the unit he worked on destroyed itself in the intervening eight months.

You could order a brand new tranny from Europe with 5.43 gears. But this would cost you many thousands of dollars--$10,000 wouldn't suprise me. (Rebuilt units are less, of course.) A dealer in Germany quoted me $8,000 on a brand new ADM unit. This price doesn't include shipping or duty or installation.

One factor is that it is easy (labor wise) to alter a ACU 4.86 front final drive to change it into a ADM 5.43 unit. It is just the rear trans that is so difficult. So you might want to buy an ACU for now knowing that you could upgrade it to ADM later if you truly go off the deep end (as I plan to do some day).

In order to avoid a botched ring and pinion swap job, I am about 75% of the way toward acquiring every factory tool mentioned in Bentley/microfiche repair manual for transmission work on these units. I didn't pay anywhere near this amount, but the price VW dealers have to pay to acquire such a toolset seems like it is tens of thousands of dollars. The 381 and 385 transmission sets alone is somewhere around $7,000 to $10,000.

I plan to acquire every single factoy tool that exists for Vanagon 4x4 transmissions and then send the tools to Wheedle along with my trans when I decide to get it modified to 5.43, asking Wheedle to use them and perform all the measurements and tests. The rest of the time these tools will sit unused in the closet, or possibly out on loan (rental?) to fellow list members in need of them.

One reason mechanics may have trouble working on these units is that there are some repair steps for the trans that Bentley left out. You have to get the *microfiche* verision of Bentley to see these steps (~$25 at Dyment).

The ADMs came with diff locks but I don't know if all of them did of if this was just an option on ADMs.

According to my book, valid codes for 4.86 ratio include ACU and ADH, it looks like. After studying my European microfiche, showing all parts for the Vanagon available over there, I have determined that the following final drive gear ratios are available for the transmission:

37/6 6.17 (16" vanagon?) 35/6 5.83 (diesel?) 38/7 5.43 (diesel?) 34/7 4.86 (DEFAULT USA) This is what all you gasoline people have. 32/7 4.57 (?)

I am told that you cannot order any of these weird gears (including the 5.43s) in the USA at a VW dealer and actually get delivery as there is no stock. No idea on what would happen if you tried to order 5.43s at a VW dealer in Europe.

Wheedle says they get around the problem of not being able to order the right gears by welding together pieces that will work. Carter's Gear Box shop also mentioned this procedure as the one they would follow. I cannot recall right now exactly what is to be welded but I would try first to get the right gears rather than perform this welding procedure.

Of the gear ratios mentioned above, I would shoot for the 6.17s unless they would obligate one to install tires so tall the tires won't fit in the Vanagon wheelhousing. Any list member that gives this matter thought (or calculation) is urged to report on what the tallest tires that will fit into a Vanagon, and hence which gear ratio we should be switching to (6.17s, 5.83s, or 5.43s).

The selection of a shop to do the transmission work seems to be of paramount importance. Wheedle and Carters come to my mind but I have no experience with these guys and seek recomendations. Any VW owner who has had trans work done by a trans shop is urged to report on their experience to help us select a shop to do the work. (Can you offer advice Bus Boys?) Once we get a particular shop up to speed on these units and the factors involved, all list members with 4x4s should probably use the same shop to keep them in practice and benefit from the combined experience.

All the trans pieces we are discussing here are Austrian parts. As you all know, the syncro along with these transmission pieces are made in the same Graz factory that makes the Mercedes G-Wagon. Thus, syncro models are the only Vanagon made outside of Germany. Therefore, syncro owners should wave at all Mercedes G-Wagons they see passing them on the road except that, of course, this would be silly as the driver would have no idea why they are being waved at.

Any person ordering a front diff from Wheedle should order the loc rite kit to be installed--ask Wheedle about this kit and be sure to get the new, quieter version of loc rite (detroit locker type thing.) The latest version of Loc Right actually be a superior balance of factors than the air operated front locker that I have. Wheedle is quite pround of having adapted this to Vanagon Syncro and I am inclined to think they know what they are doing.

Finally, before closing, it is advisable whenever working on the front diffs to upgrade them to the beefier models with four small differential gears rather than two small differential gears (pinions?) as we have now. There are some "heavy duty" components that are optional for the front final drive whereas USA models are only medium duty. But this subject is too complicated for me to go into now and shall have to await another post.

Here is a note from my hard drive:

"My Locking Front Diff The new transmission I bought with front locking diff has a part number of 094 409 410 SOP and code number ADK 248 (manufactured in early 1988?). None of these numbers are in my german microfiche that I can see, however!"

"ACU 12266 is the code on my 87 non-locking diff. (meaning that Styer Daimler Punch whatever spelling made this unit on 12/26/86)"

Now that I have told every body about ADMs, can someone tell me about ADKs? That is, what the heck diff do *I* have?????????????????????

>Finally....I'm back on the list and also doing something about my front >drive. Got through the summer, but now that winter's coming, I've got to get >front diff and driveshaft back in shape! > >I've located a source of new front drives, but the designation on the units >is "ADM", which is different from what Bentley and mine show. Does anyone >know what this desig. might mean? Locking capability? Or different gear >ratio? John, at Weddle Engr., couldn't find the answer, so I told him there >might be someone on the list that would know. Sure would be great if it would >work in my '87. And it might be a source for you fellow syncro owners who >ever need help. > >Great to be back!....now if I can keep up with the mail! > > >Dan > > > > > > > ___________________________________ Derek Drew drew@interport.net (main address for e-mail) derekdrew@aol.com (alternate/backup address, checked infrequently)


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