ZF 5DS-25/2 Transaxle Inversion

[Lance]

I’m know I’m going over old ground again, but just in order to confirm, I'd appreciate some input from those more expereienced. I’ve had my ZF inverted, but I’m checking the work that’s "been done". The place that did it was a bit casual about the whole thing and I want to be sure that it’s been done correctly. Having said that, there seems to be few critical items and I don’t want to pull it apart unnecessarily.

Apart from the work associated with the physical inverting of the box and reversing the crown wheel, the items that seem to get mentioned are:

1 Various fill holes and drain plugs. I think we’re OK there.

2 A breather gets mentioned occasionally for hard use. Not required for street use or is this recommended anyway? What’s the view?

3 A trough under the gears feeding oil to the crown wheel. This is supposedly in place in the standard GT40 configuration (inspection plate on top) so no action required?

4 Drill a few holes into the bottom of the wall between the gearbox and crown wheel housings. I assume this is for drainage to change the oil (?), but this isolated oil could be removed by a suction tube, or are they required to distribute the oil after filling? I would have thought not. If they’re not required and they’re not in place, I won’t be pulling it apart to install them.

5 Output shaft bearings have to have oil input holes(?) on top and the bottom ones filled in. This seems like the item that could be a problem if it’s not been done. Does anyone have a photo of what this looks like? Are these the square openings in the bearing housing shown in the manual? What are the existing holes filled with? I would have thought welding would have distorted everything. What is recommended?

Is there anything I’m overlooking? I don’t want to break this transaxle. The trouble I have is that, in Perth, there is no-one that knows anything about ZF transaxles.

Any help or photos greatly appreciated.

Cheers,

Lance

 

[Jim Rosenthal]

You might write to RBT, or to Pantera1889 on this forum. Both know a lot about ZFs and have done this. Also Dennis Quella at Pantera Performance in Colorado, USA.

 

[Julian]

ERA's website has a free build manual for download (the free version omits the pictures, but you can get the full version for something like $30), it describes the inversion process.

Primarily it's the drain holes between the R&P and main gearbox sections for free oil flow, plus the drain and fil holes. Basically that is all ERA are recommending, but take this as more a minimum as I'm told Lloyd at RBT goes above and beyond in his inversions. That said I have not heard of any ZF failures arising from the more simple minimum mod and I believe this is all Dennis Quella and Larry Stock (Pantera Parts Connection, NV) do for an inversion.

 

[Mike Drew]

I dropped off a couple of Pantera Dash-2 gearboxes at RBT on Saturday for a friend. By lucky coincidence both Lloyd Butfoy and Oliver Ring were there, and we had a nice BS session.

(It was interesting hearing about the ZF test rig that Oliver uses; each new RBT gearbox is run on a dyno (that he purchased directly from ZF) that has an electric motor on the input shaft, and two motors on the output flanges. He can load the gearbox both ways (that is, use the input shaft motor for drive, and use the output motors to apply a braking force, and vice-versa). In this way, they test all the shifting characteristics, and listen for noise etc. to ensure that the thing performs as it should when it goes out the door).

Anyway, one of the gearboxes I delivered is getting repaired for use in a Pantera; the other is going to get overhauled and flipped for use in an SPF GT40. I'm going to go back down there in a few weeks and photograph the entire process, and if Ron approves, I'll generate a new thread here.

It won't be a 'how to' piece, as I've agreed to protect some of Lloyd's trade secrets. Instead, it will give insight into the not-insignificant amount of work that goes into rebuilding one of these gearboxes, as well as the extra work that is required to invert them for GT40 operation. Hopefully it will enable a greater appreciation of the handful of experts who are capable of reliably performing such work, such as Lloyd Butfoy, Dennis Quella, Ron McCall, Les Gray, Guy Trigaux, and a handful of others....

 

[Vinny]

Here I am with a ERA gt40 where the zf trans does not have the oil level hole installed on the passenger side per ERA. There is an existing bolt on the side just rear of where ERA recommends installing an oil level hole. Why can't this existing be used? It's at the same elevation. Am I missing something here?

 

[Bob Putnam]

Here I am with a ERA gt40 where the zf trans does not have the oil level hole installed on the passenger side per ERA. There is an existing bolt on the side just rear of where ERA recommends installing an oil level hole. Why can't this existing be used? It's at the same elevation. Am I missing something here?

I believe that bolt retains one of the internal shift shafts (or something...). You need to put in a separate fill-level hole.

 

[Jack Houpe]

Lance I have some photos of a -2 pantera zf being split and some photos of my M1 ZF which I had to take apart to switch the shift lever from left to right. PM me your email and I get them to you.

I found that cutting a 2 in hole in my work bench made like much simpler as you could put the input shaft through the hole and start stacking sections of transaxle.