ZF questions

Brian Stewart
Supporter
Looking for some answers from folk who likely know a whole lot more about ZFs than I do. I have just taken delivery of two ZF transaxles after purchasing them sight unseen with a friend some time ago and having them sit in a warehouse in California for four years (long story). Anyway, they are a ZF DS25-1 (serial number 1031 001 061 on the tag and S/N 1031 401 054 on the housing) and a ZF DS25-2 (serial number 1031 002-020). I'm inclined to keep the 25-1 as (and correct me if I am wrong) it will not need flipping and is more original. The DS-2 will need flipping I am guessing (see last picture). My friend will keep the -2 to put in his McLaren M6GT project. Haven't had a chance to open either of them up yet, so no idea what the insides are like, but both turn very smoothly with no odd noises. Only blemish I can see from the outside is a small weld in the case of the -1 (see picture). So, questions... What cars are these likely out of? Am I silly to prefer keeping the -1? Where can I get a bellhousing to mate the -1 to an SB Ford (1969 351W)? Looks like a Chevvy bellhousing on the dash 2 - am I correct? What is the angled pipe on the side of the -1 (2nd to last picture)? Thanks in advance.
 

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Brian Stewart
Supporter
and another question... Can someone please give me the contact details of whoever it is (Mark?) who sells ZF top mount plates. Thanks.
 

Brian Stewart
Supporter
Thanks Bob. I'm not an eBay user - do you have any other contacts for Mark? If not I may have to join eBay...

Cheers,
 

Jim Rosenthal

Supporter
Brian, PM Pantera1889 off line. (Ron McCall) He knows a few things about ZF 5DS transaxles; he may be able to help you out. He did mine.
 

Brian Stewart
Supporter
Thanks Jim. Will do. So, I have taken the top off both boxes. The DS-2 looks as though it has never been used. The DS-1 appears to have been used, but all internals appear to be in very good condition. However, it looks very much as if the crownwheel and pinion on the DS-1 have been flipped to non-GT40 orientation (presumably for the M6GT application it was originally bought for) as both boxes have the crownwheel on the right hand side, if looking from the rear and with the box in GT40 orientation. My interpretation of the DS25-0 workshop manual I have has the crownwheel on the left if the box is in GT40 orientation. In other words, a GT40 ZF should have the crownwheel on the left of the pinion when viewed from behind. Am I interpreting it correctly?

Thanks.
 

Jim Rosenthal

Supporter
Brian, it doesn't matter which side the crown wheel is on; you'll still go fast either way. Of course, if you don't want to go backwards quickly, you WILL have to orient the crown wheel and pinion properly.
 

Brian Stewart
Supporter
Part way through the flipping process for the DS25-1 and everything seems to be going well. However, it looks as though this cover (first picture) needs to be swapped to the opposite bearing (second picture) for everything to fit back together once the differential is flipped. Is this correct? I cannot find any reference to this part in any of the descriptions for flipping ZFs.

Thanks.
 

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Part way through the flipping process for the DS25-1 and everything seems to be going well. However, it looks as though this cover (first picture) needs to be swapped to the opposite bearing (second picture) for everything to fit back together once the differential is flipped. Is this correct? I cannot find any reference to this part in any of the descriptions for flipping ZFs.

Thanks.
The covers are handed Brian. Have you got the build manual ??

Bob
 

Brian Stewart
Supporter
Thanks Bob. There is only one cover (cap). I have a DS25-0 manual and a DS25-2 manual (can't find a -1 manual on the web anywhere) and the cover does not appear to be shown in the exploded diagram for the -0 but appears in the -2 manual (Figure E1031.003) as "929 Cap". In that diagram it certainly appears to be located on the bearing carrier that fits against differential on the toothed side of the crown wheel. So, my assumption is that if the crown wheel is flipped, the cap must be moved to the other bearing carrier so that it once again fits against the diff on the toothed side of the crown wheel.
 
Thanks Bob. There is only one cover (cap). I have a DS25-0 manual and a DS25-2 manual (can't find a -1 manual on the web anywhere) and the cover does not appear to be shown in the exploded diagram for the -0 but appears in the -2 manual (Figure E1031.003) as "929 Cap". In that diagram it certainly appears to be located on the bearing carrier that fits against differential on the toothed side of the crown wheel. So, my assumption is that if the crown wheel is flipped, the cap must be moved to the other bearing carrier so that it once again fits against the diff on the toothed side of the crown wheel.

That would be right Brian but it might not be correct in mesh, you might have to play with the shims.

Bob
 
Both of your gearboxes come from Panteras; your Dash-1 is from a 1971 Pantera and your Dash-2 is from a later car (or at least, both wear Pantera gearbox part numbers). Because both are Pantera gearboxes, both will require flipping to be run in a GT40 orientation. I don't know the vintage of your later gearbox, but '71-74 Ford-era Pantera gearboxes did not have any identification tag on the case, so yours is either a 1980s-vintage Pantera gearbox, or perhaps it came from some other car. The non-Pantera (Chevy?) bellhousing would tend to suggest that perhaps it was originally fitted to some other car, i.e. somebody who needed a Pantera-style gearbox could have purchased it directly from a ZF source. There's no way of telling.

I presume your friend's McLaren project will run in the GT40 orientation also?

Although there is nothing specifically 'wrong' with either style of gearbox, generally the Dash-2 is considered superior in most ways--stronger, more robust, and with much greater parts supplies. The case is physically a bit larger and heavier, so you're right--the Dash-1 architecture and physical dimensions are identical to the original GT40 gearbox and thus are more 'right'.

Note that your Dash-1 is setup with cast iron side covers with bolt bosses that splay outwards at a 45-degree angle. The gearbox case itself is only secured to the bellhousing around the periphery of the front case opening with four bolts; the original GT40 bellhousing (along with the Dash-1 Pantera bellhousing, and Mangusta bellhousing) had provisions for two more long bolts to engage these holes in the side plates.

I've seen several original-style GT40 bellhousings on the market (Safir, Gelscoe, Cushman), which have bosses to accept these bolts which are not machined, so you would likely have to open those holes up. The diameter of a Dash-1 and Dash-2 case mouth is different, so the bellhousings won't simply interchange. The back of the bellhousing would need to be machined to mate with the front of the gearbox case.

Also, the Dash-1 input shaft is shorter and uses a different spline pattern. In the Pantera, it didn't actually reach the back of the crankshaft, which was more than a little inconvenient; instead, a pilot bearing adapter had to be used which ran in between the pilot bearing and the snout of the input shaft. I confess I don't know how the system works on the GT40, but would presume that the front-to-back dimension of the bellhousing is shorter, and thus the Dash-1 would engage the back of the crankshaft properly; in that case, the Dash-2 would likely be too long and some cleverness would be required.

Perhaps the Dash-2 GT40 bellhousings have thought of that, and are slightly longer? I really don't know, but need to get smart on this stuff one of these days.

Allow me to cheat a little bit, and poach from a long-ago post on a similar subject that I made elsewhere on this forum:

=====

I know of two sources for GT40 clutch bits, and suspect a third:

1) Gelscoe, in the UK
2) Safir, in the USA
3) Jay Cushman, in the USA (although he doesn't list these parts on his website--he may produce them, or may source them from someplace else? Jay?)

Safir has cast up an original-style bellhousing (I don't know if it's "original-original" or a later design, but it is visibly different from the Gelscoe offering), but uses a super-modern (and expensive) multi-disc clutch from McLeod.

Here are some photos of the Safir setup:

Flywheel.jpg


ClutchFlywheel.jpg


FinishedBellhousing.jpg


BellhousingLogo.jpg


Bellhousings.jpg


SafirClutchBellhousing.jpg




Meanwhile, here's a photo of the Gelscoe bellhousing. Compare it to the Safir unit above; the Safir bellhousing seems to have an integral cooling air scoop or something on the bottom of it? If it hangs down low, I suspect it would become a skidplate before long. The Gelscoe bellhousing has vents on the top and bottom:

344.jpg


Both units seem to be sized (and drilled) for the more common Dash-2 ZF gearbox. The Dash 1 and Dash 0 use only four bolts instead of six (plus two lateral bolts), and the opening is physically smaller.

=====

Have you seen the ERA instruction manual to flip a Pantera gearbox to GT40 orientation? The ZF manual doesn't address this procedure at all, for it presumes that whatever gearbox you are working on is coming out of a car, getting rebuilt and going right back into the same car, thus it's just a traditional overhaul manual, rather than a modification manual. The ERA manual leads you in the right direction to perform the modifications necessary.

The ZF is a very sophisticated and finicky piece of kit. Even people with lots of experience rebuilding transmissions can soon find themselves running out of talent when trying to cope with one of these transaxles, so if this happens to you, there's absolutely no shame in it. Lloyd Butfoy told me that a substantial percentage of the gearboxes he gets in for maintenance come to him in pieces, where owners or even transmission specialists blew the gearbox apart and then quickly found themselves in over their heads.

Since you're in New Zealand, you're in great luck. There are only a handful of people worldwide who are certified as specialists in these animals, and one of them is right there next to you. Paul Donderwinkel is his name, and his e-mail address is [email protected]

(Paul emigrated from London some years back, and has the distinction of owning a very special Pantera, built as a prototype in the 1980s for Carroll Shelby, and powered by a twin-turbo Dodge from new!)

Even if you are determined to pursue the DIY route, I would still touch base with him. He will be a great ally, is likely to have parts on hand, and if not, he can get them easily enough from Lloyd Butfoy as he receives regular shipments. I would strongly urge you to have him take a look at your gearbox, because now is the time to find out if your 2nd gear synchro is trashed, or whatever. Although it's certainly fun and rewarding to perform ZF surgery on your own, it's also filled with the prospects for screwing up something extremely expensive and difficult to replace (particularly with the Dash-1), and sometimes it pays to have some expert advice--or just to hand the gearbox over with instructions to go through it and make it perfect.

Keep us posted and let us know how it turns out! :thumbsup:
 

Brian Stewart
Supporter
Thanks Mike. Very useful information. I do have an ERA manual, but I shall certainly touch base with Paul Donderwinkel as well.

cheers,

Brian.
 

Brian Stewart
Supporter
The crown wheel has been flipped and side flanges are on. I have ended up with a crown wheel to pinion clearance of 0.16mm (0.0063"). I blued the teeth and get a mark just over halfway down the tooth, as in the the picture below. The various manuals and references I have recommend a lash of between 0.15mm and 0.25mm, depending on which one you read. The ERA manual says the correct lash is engraved on the crown wheel. The numbers on my crown wheel are as below. Can I leave my lash at 0.16mm or should I change it? Easy enough to do by playing around with the shims.
 

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Brian, The pattern/pic # 2 is the drive side of the tooth, #1 is coast side. Of the two drive side pattern is slightly more critical . Since R&P have been used before I would clean the bearing blue off and use a good magnifying glass to try & identify tooth wear pattern & depth of contact pattern first, maybe even take a good pic of both sides of teeth & enlarge/print to verify your getting the same correct depth of engagement it had in its previous setup. I take it you have the correct/same pinion depth as the previous setup along with setting the preload on both the pinion & carrier bearings in order to obtain this tooth marking.
 
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