ZF pantera transaxle?

[PaulGT40]

Well there it is 30 years of dust and all. I am going to pull the 500 HP high nickel roller cam and rocker engine I got with the Fiberfab and start with the Pantera transaxle and engine. It's supposed to have roller rockers and some other internal mods. Any advice would be much appreciated.
Thanks
Paul

 

[Julian]

One more question for someone, the guy had a 4:11 ring and pinion put in but still has the originals, is it worth trying it with this ratio or just put the original back in.

Here's a neat resource from Mike Dailey one of the great Pantera guys, it's a gear ratio speed calculator.

It's set at the std Pantera Dash 2 gear ratios and final drive (4.22), which you can change to any available gears from RBT to find your ideal set up. I don't know that a 4.11 final drive was available, maybe in the early Dash 0?

 

[PaulGT40]

The guy couldnt remember the exact ratio he had put in but he figured the stock ratio was to high for a sandrail, he also said the gears cost him $3200 back in the 70's. Fortunatly he still had the originals and fortunatly for me he never finished the rail.

 

[Bob Putnam]

Paul,

I think what he meant is that he had to maintain the Pantera orientation because the GT method puts the engine too low for a sand-rail application.

Reversing the ring and pinion requires some special tools (or some creative work). IIRC, there have been some previous threads on the process.

There are instructions for the inversion process in the ERA manual (available as a $30 download). Of course, you can also keep the current orientation at the expense of a higher CG.

 

[Dave Wood]

Although he may have had the transaxle correct, that's no Cleveland attached to it. It looks like a 302 engine with some 5.0 valve covers. If it was set in there in the 70s it would have to be a 289 or 302, it could be a 351W, but there is not enough picture to determine.

 

[PaulGT40]

Maybe hes confused, although I asked him again and he said he paid $ to have it flipped, new bell housing and new bottom plate, He never heard of a GT40 WOW. I asked if he had the old parts he said no, just the extra ring and pinion. I guess it doesn't matter I will have to flip it. I looked at it very close and can't see the reason to invert. Does it lower or raise the axle height?
Thanks

 

[Dean Lampe]

Paul, what is he going to do with the sand rail? It looks like a fun project.

 

[PaulGT40]

I am giving it to my Daughter with the audi transaxle and chevy motor.
Bummer about the ford motor, never really looked at it, its no 351C is right. I called the guy this morning and asked him about it. He bought the ZF in the 70s I was there! He took it to a guy in Tucson to finish in 1992. The guy stole the $6000.00 shocks and etc's and swapped the 351C for whats in it now, a regular 5.0 I shoulda looked closer. Oh well at least I got my son A ZF and my daughter a sandrail

 

[Randy V]

I'm not at all put-off by a member here with a Valkyrie.... I always liked them even though not a faithful replica of the GT40.. Good luck with your project and welcome to GT40s.com!

 

[MReid]

Welcome, Paul! You have quite a project on your hands, but everyone here will be very willing to help and offer advice. Scan through some of the build logs and you will see everything imaginable in a build. You will fit right in!

 

[Jac Mac]

Its either a 289 or 302 ( 289 if my suspicions are correct ) check it out more carefully as per my thoughts on the other thread. The 'robber' may have actually done you a favour!

 

[Mike Drew]

Paul,

The gearbox that you are showing in the photos is a Pantera ZF 5DS-25/2 gearbox, which is a VERY good thing. If it's in decent condition it's worth about $6000-7000, and the extra ring and pinion are worth another $2000 or so. As an unknown quantity in need of a rebuild (which I would suggest that yours is), it's only worth $4000 or so.

The stock rear end ratio was 4.22, which sounds pretty low, but both 4th and 5th gear are overdrive, so a 4.22 gives about a 160 mph top speed. Changing to a 4.11 would actually make the car marginaly faster (but not as quick), so it's likely that dune buggy man switched to something more appropriate. ZF doesn't make a 4.11 anyway. Final drive ratios were 3.77, 4.22 (stock) and 5.25, the latter of which would seriously limit your top speed, but if he changed it that's probably what he used--or something along those lines. Assuming he geared it down (for off-road performance) and not up (for higher top speed), your best bet would be to retrofit the original ring and pinion. The gear ratio will be engraved along the circumference of the ring gear.

Rebuilding a ZF is NOT a job for an amateur--in fact it's not even a job for a professional transmission shop that has never seen or worked on a ZF. They are finicky, tricky to set up (although it's apparently not all that hard if you know how to do it AND you have the numerous special tools required). Too, inverting the gearbox to run in the original GT40 configuration is a non-trivial exercise, as there are several internal modifications that need to be made to the case.

POCA, the Pantera Owners Club of America, sells a reprint of the ZF shop manual (which covers both the 5-DS-25 and 5-DS-25/2, but oddly not the /1 variant) through the club store, at

https://www.asajayinc.com/pocastore/

The manual is $23, and is very well-written for a professional. I suspect reading it will convince you of the wisdom of entrusting the job to one! There are numerous internal tolerances which must be set up very exactly, using a bunch of extremely fine shims. Unless you have a bunch of these exact shims on hand, and know somebody locally who wears a pointy hat with moons and stars on it who works on high-end gearboxes, I'd plan on shipping it off to one of the pros and then waiting a LONG time to get it back.

Plan on budgeting a minimum $3000 to have your gearbox configured for the GT40 application and freshened, knowing that the price could go down slightly, or go WAY up (like, $6000 or more) depending on what it looks like inside. There is nothing worse for a gearbox than sitting for 30 years unused; it's quite possible that it will be extensively rusted/pitted above the 'waterline' of the oil that was (hopefully?) inside this whole time.

You will also have to buy a new bottom (now top) cover incorporating mounting lugs, from which the gearbox will hang. That's another $500 or so, although you will probably be able to trade in your old bellhousing for a few hundred bucks.

Have you decided how you want to actuate your clutch? The Pantera used an external slave cylinder, but most GT40 guys are running a hydraulic internal throwout bearing. You're fortunate in that your gearbox has the setup for the external slave; if you choose to use that (which personally I would recommend), you'll have to conjure up a method of mounting the slave cylinder. Some GT40 bellhousings are drilled/tapped to support a slave cylinder mounting bracket and others aren't. There are several different schemes available; others here will have more specific guidance.

If you go the internal throwout route, that will render the L-shaped arm the slave cylinder actuates, and the internal cross shaft it's connected to surplus to your needs. To give you an idea of what those parts are worth, check out the Panteras by Wilkinson website. Here's the L-shaped clutch arm:

Panteras by Wilkinson On-line Store

and the bellhousing:

Panteras by Wilkinson On-line Store

Here is the page that shows the cross shaft and clutch fork and etc.:

Pantera Store

The retail value of the cross shaft and fork pieces combined exceeds $500. With the bellhousing and clutch arm and stock bottom cover you're nudging against $1000, and I'd see about offering up those parts as a partial trade towards the cost of your rebuild.

Good luck!

 

[PaulGT40]

I took the cover plate off and it is coated in some kind of assembly grease very clear grease not dark. It looks new no sign of anything but shiny gears.
Call me a fool I am trying the procedure to invert. I bought the manual. It wont be the first stupid thing I've done. I do laser alignment for a living where an 8 thou beam travels through 14 mirrors over 18 feet and must be aligned within a few thou. I have dial indicators etc., etc.,etc. I figure you never lose anything trying to learn something new, besides my son is going to help and maybe he will learn something.
Paul

 

[Mike Drew]

I took the cover plate off and it is coated in some kind of assembly grease very clear grease not dark. It looks new no sign of anything but shiny gears.

That is GREAT news! Consider yourself very lucky!

Call me a fool I am trying the procedure to invert. I bought the manual. It wont be the first stupid thing I've done. I do laser alignment for a living where an 8 thou beam travels through 14 mirrors over 18 feet and must be aligned within a few thou. I have dial indicators etc., etc.,etc. I figure you never lose anything trying to learn something new, besides my son is going to help and maybe he will learn something.
Paul

Well, the manual is great for doing a simple rebuild, or changing the ring and pinion. But as far as I know, nowhere in the manual is it detailed what must be done to invert the gearbox because that eventuality was never considered. They, logically enough, assumed that one would be removing a gearbox from a given application, working on it, and then reinstalling it.

There are several holes and internal passages that need to be drilled in the case when you flip it over. There are also other holes that need to be plugged (I believe using ball bearings?) or else the side bearings will run dry and seize. Last time I was at Lloyd's shop, he showed me two home-brew invert jobs that went bad, which totally trashed substantial (read: $$$$$) portions of the gearbox; the customers then had to send the gearboxes to him to be salvaged and the job done properly.

You will probably have to machine special tools and jigs to hold the various components you'll be working on (which is probably child's play for you) before you start actually doing anything substantive.

It sounds to me like you are much better equipped (both in terms of tools, and skills) than most of us to do the job. But having a drawer full of sharp knives, a steady hand and a book on physiology doesn't qualify you to do brain surgery. If all you're going to do is rebuild the gearbox, you're probably okay. But if you want to flip the thing on your own, do yourself a favor and speak to an expert first (which I am definitely NOT) and get a VERY clear and exact procedure for the modifications that are absolutely necessary. It's involved, so plan on taking notes, making diagrams etc.

It sounds like you scored big-time when you found this gearbox. Nothing could be better than a zero-time ZF that is in perfect shape inside. I'd hate to see it trashed.

 

[Ron McCall]

He is probably speaking of the ERA manual that Bob Putnam mentioned in a earlier post..NOT the ZF manual.

 

[MReid]

I have ERA's manual with the procedure for flipping the transaxle. It seems pretty straight forward, but there are requirements for special tools or a lot of cussing. I can send you a copy of the necessary pages if you need them. Just send me a PM.

 

[Gary Kadrmas]

I am not a ZF expert, but I have gained enough wisdom over the years to understand that I hate paying someone else to do work that I can do.

Along with that wisdom, I also understand that making a stupid (unknown at the time) mistake will take double the money to get the fix unfixed and fixed right.

So the conclusion is: Best money spent sending a job to an expert, but make sure you do your homework on the expert first.

 

[Jac Mac]

I am not a ZF expert, but I have gained enough wisdom over the years to understand that I hate paying someone else to do work that I can do.

Along with that wisdom, I also understand that making a stupid (unknown at the time) mistake will take double the money to get the fix unfixed and fixed right.

So the conclusion is: Best money spent sending a job to an expert, but make sure you do your homework on the expert first.

In my 40 odd years in this 'trade' I have yet to find a trans- motor- or rear axle assy that I cannot strip, modify, rebuild. Now some will say , yes Jac but maybe you have a bit more knowledge or experience than most of us. That may well be the case, but I have never worked on a ZF, that said if a guy fronted up at my front door tomorrow and asked if I would look after a car equipped with one I would have no problem with doing so & I can assure you I would not be sending the damn thing halfway around the world for an 'expert' to refresh between meetings on the time frames being mentioned in these pages.( In fact after all this time, the more 'experts' I meet the less faith I have in them.) Im sure from pics I have that race teams were able to rebuild these trans overnite. Now if your trans in this case is in good condition inside and has not suffered any wear from a prior botched assy job, then the ring gear flip should be a simple matter of maintaining the side brg preload and the backlash as installed now. I see no reason to even touch the pinion depth settings. Then you would have to drill holes etc & perhaps block a few existing ones to establish a suitable oil level setup -- this area would require some thought & in depth knowledge or appreciation of oil flow dynamics in practice, but its common sense stuff, not rocket science.

This is one subject that would be excellent to get the 'new' trans 'how too' forum of the ground. The only downside being that parts for these trans seem to be available from only a couple of sources and in many cases are on back order.

 

[MReid]

Wow, Jac Mac, you actually just proved your point! What you described is basically the procedure. Only additional step of any merit is to ensure appropriate clearance on the other side of the case where the ring gear will now sit and then check the side bearing preload. It does seem there are some challenges with removing the ring gear bearings and I would be particulalry careful with this step.

 

[PaulGT40]

Jac Mac,
You are my kinda guy. An expert is someone who has the determination, the patience, and the willingness focus on the task at hand and to ask questions when needed.Yes experience is important but you only get it by having the above. I will certainly make a photographic record of my ZF flip and post it for others whom might be fortunate enough to acquire a ZF. At any rate not all of us have the money to buya ZF and then pay someone an equal amount to set it up. My son (Justin) is certainly going to learn something on this Project. A person is only as smart as he will allow himself to be.
Paul Hall

In my 40 odd years in this 'trade' I have yet to find a trans- motor- or rear axle assy that I cannot strip, modify, rebuild. Now some will say , yes Jac but maybe you have a bit more knowledge or experience than most of us. That may well be the case, but I have never worked on a ZF, that said if a guy fronted up at my front door tomorrow and asked if I would look after a car equipped with one I would have no problem with doing so & I can assure you I would not be sending the damn thing halfway around the world for an 'expert' to refresh between meetings on the time frames being mentioned in these pages.( In fact after all this time, the more 'experts' I meet the less faith I have in them.) Im sure from pics I have that race teams were able to rebuild these trans overnite. Now if your trans in this case is in good condition inside and has not suffered any wear from a prior botched assy job, then the ring gear flip should be a simple matter of maintaining the side brg preload and the backlash as installed now. I see no reason to even touch the pinion depth settings. Then you would have to drill holes etc & perhaps block a few existing ones to establish a suitable oil level setup -- this area would require some thought & in depth knowledge or appreciation of oil flow dynamics in practice, but its common sense stuff, not rocket science.

This is one subject that would be excellent to get the 'new' trans 'how too' forum of the ground. The only downside being that parts for these trans seem to be available from only a couple of sources and in many cases are on back order.