ZF's from the "Ford Dealer" parts department were ONLY about $800 new across the counter then.
I know a few people that bought a few of them.
They weren't even worth fixing then.
About 950 hp will do this with a standart zf .
Only 1 time full throttle
What about the mendeola transaxle ?
Renault is rated lower than the zf.
The zf is rated 500 nm torque max.
The Renault about 250nm.
Only 1 time full throttle
What about the mendeola transaxle ?
Renault is rated lower than the zf.
The zf is rated 500 nm torque max.
The Renault about 250nm.
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Peter,
You're assuming this damage was due to too much torque for the ZF to handle. Perhaps the person who rebuilt this particular ZF didn't know what they were doing. Perhaps the R&P should have been replaced when this ZF was rebuilt. There are too many variables involved to simply blame the design of the ZF.
It's my understanding that most ZF failures occur in racing situations and involve broken input shafts on cars with slick tires. On a street driven Pantera, the tires limit how much torque can be transmitted through the transaxle. A 950 Hp motor will simply spin the tires under full throttle.
The best transaxle option for you, without spending $$$$$, is probably a brand new RBT ZF.
You're assuming this damage was due to too much torque for the ZF to handle. Perhaps the person who rebuilt this particular ZF didn't know what they were doing. Perhaps the R&P should have been replaced when this ZF was rebuilt. There are too many variables involved to simply blame the design of the ZF.
It's my understanding that most ZF failures occur in racing situations and involve broken input shafts on cars with slick tires. On a street driven Pantera, the tires limit how much torque can be transmitted through the transaxle. A 950 Hp motor will simply spin the tires under full throttle.
The best transaxle option for you, without spending $$$$$, is probably a brand new RBT ZF.
Racing tires . The zf was rebuilt direct from zf.
I am looking to change my stock 4.22 ring and pinion to a 3.56 or 3.78 anyone got one? will swap or sell after change. Note it is a 25-1
Larry 772-284-0331
Larry 772-284-0331
It would be worth checking interchange between -1 and -2 on the ring & pinion with someone like Lloyd at RBT. Is it the -1 that has a shorter input shaft and uses an extension?
GT4, that picture is a mind blowing example of the ZF limits. I would contact Loyd as he sells many different racing transmissions, his father was the trans guru on the Shelby GT-40 program.
Chris,
I think GT4Peter's unfortunate experience is more of a lesson in how to service your transaxle than it is in the limitations of the ZF trans.
You'll recall when Peter bought this ZF it was essentially a box of parts. The pinion gear was pitted but he decided to save a few $ and see how long it would last. The first time he used it, he got his answer.
This is also a reminder to use a known expert when rebuilding your ZF. This means using the manufacturer (RBT) or one of a known handful of Pantera shops. Sure, there are lots of people that are perfectly capable of servicing a ZF trans but it's an expensive gamble if you aren't 100% sure of their ability. Don't just send it to a transmission shop. If I'm not mistaken, GT4Peter used an ex-ZF company mechanic for his rebuild.
ZF "washed their hands" of our transaxles about 25 years ago. At that time they sold the rights, tooling and entire inventory of parts to Lloyd Butfoy's father, Roy. RBT has been the manufacturer ever since.
I think GT4Peter's unfortunate experience is more of a lesson in how to service your transaxle than it is in the limitations of the ZF trans.
You'll recall when Peter bought this ZF it was essentially a box of parts. The pinion gear was pitted but he decided to save a few $ and see how long it would last. The first time he used it, he got his answer.
This is also a reminder to use a known expert when rebuilding your ZF. This means using the manufacturer (RBT) or one of a known handful of Pantera shops. Sure, there are lots of people that are perfectly capable of servicing a ZF trans but it's an expensive gamble if you aren't 100% sure of their ability. Don't just send it to a transmission shop. If I'm not mistaken, GT4Peter used an ex-ZF company mechanic for his rebuild.
ZF "washed their hands" of our transaxles about 25 years ago. At that time they sold the rights, tooling and entire inventory of parts to Lloyd Butfoy's father, Roy. RBT has been the manufacturer ever since.
I agree, David. FWIW, with a very high torque engine, it's well known that the aluminum ZF cases 'spread' under load, moving the ring and pinion apart a bit and unloading the differential side gears- which usually fail. Originally, the GT-40 ZFs had cast aluminum side covers, no crossbolts in the access cover and no bellhousing brace-bolts. Those parts and more were upgraded to steel or cast iron in an attempt to stiffen up the ZF cases for LeMans, at the strong suggestion of Ford engineering. Ford went with a Collotti transaxle for the 427 GT-40s and had even more trouble with that POS.
IMHO, if you're going to go pro racing, use a pro racing transmission and put up with the fitment adaptions, shifting ills etc. The unsynchronized Hewland DG 300 (& others) was a popular replacement back in the day for F-5000, Can-Am etc, and the boxes wore out very fast but worked. Hewland is still in business in England and a quick Google search shows a few Hewlands for sale at ZF prices. There's no synchronizers because the gears are wider- which makes them stronger but requires even more care in gear-speed-matching than with the ZF.
IMHO, if you're going to go pro racing, use a pro racing transmission and put up with the fitment adaptions, shifting ills etc. The unsynchronized Hewland DG 300 (& others) was a popular replacement back in the day for F-5000, Can-Am etc, and the boxes wore out very fast but worked. Hewland is still in business in England and a quick Google search shows a few Hewlands for sale at ZF prices. There's no synchronizers because the gears are wider- which makes them stronger but requires even more care in gear-speed-matching than with the ZF.
All good points Jack, plus the added benefit of easily changing out gear ratios to match the various tracks.
My last race weekend in Sonoma I had the Hewland apart 3 times and back together ready for the next session. Try that with a ZF!
I seem to recall reading the later ADA Si Pantera ran a Hewland transmission?
My last race weekend in Sonoma I had the Hewland apart 3 times and back together ready for the next session. Try that with a ZF!
I seem to recall reading the later ADA Si Pantera ran a Hewland transmission?
This was not mine zf , youst one from a friend. I bought a new ring and pinion for mine. At this time, we are closer to make more than 800 nm hapen in a zf.
We tried to call rtb and zf direct , we also bought a quife and we did a lot of basic groundwork with the zf now. I am happy to say : we are able to do it better now !
Friends from a big austrian aircraft company redesign ring and pinion to a modern "klingenberg" theeth with a bigger area and some other oil skills , so that the peassure between the teeth is not to high. All the new parts we develop now are at minimum factor 1.5 better than stock. We also do a new aluminium housing in cooperation with zf . Also the ratio is changed to about 4.0 , I think its a nice ratio for the engines with more power than stock.
And yes , this all is done by us. One had worked at zf and have done maybe more than 100 25-2 ,
So he know everything about the zf. Also he have better sinter plates for the diferential. The man who develop the new ring and pinion works for more than 20 years in the car and aircraftindusteoe and develops several gears for turbopropengines or mercedes.
I am happy to initiate this all, If somebody like a new ring and pinion please pm me.
We tried to call rtb and zf direct , we also bought a quife and we did a lot of basic groundwork with the zf now. I am happy to say : we are able to do it better now !
Friends from a big austrian aircraft company redesign ring and pinion to a modern "klingenberg" theeth with a bigger area and some other oil skills , so that the peassure between the teeth is not to high. All the new parts we develop now are at minimum factor 1.5 better than stock. We also do a new aluminium housing in cooperation with zf . Also the ratio is changed to about 4.0 , I think its a nice ratio for the engines with more power than stock.
And yes , this all is done by us. One had worked at zf and have done maybe more than 100 25-2 ,
So he know everything about the zf. Also he have better sinter plates for the diferential. The man who develop the new ring and pinion works for more than 20 years in the car and aircraftindusteoe and develops several gears for turbopropengines or mercedes.
I am happy to initiate this all, If somebody like a new ring and pinion please pm me.
Ps : not only the zf housing is the problem.
The teeth are to hard. Ring and pinion is about 1.2 mm hardened. Sorry for my english.
This means that the teeth is hardened complete at the small side.
Here starts the damage. Small parts break out. The next damage is on the bearing from the pinion. The "play" between those parts getting bigger. Now its the time and its only a matter of time and it chrash. The housing problem have only rtb. Theire mould is not hot enough and the quality from the aluminium is ok but the have some problems . Old zfs or the new zfs for the gt5s should not have those problems.
The teeth are to hard. Ring and pinion is about 1.2 mm hardened. Sorry for my english.
This means that the teeth is hardened complete at the small side.
Here starts the damage. Small parts break out. The next damage is on the bearing from the pinion. The "play" between those parts getting bigger. Now its the time and its only a matter of time and it chrash. The housing problem have only rtb. Theire mould is not hot enough and the quality from the aluminium is ok but the have some problems . Old zfs or the new zfs for the gt5s should not have those problems.
some intersting comments about improvments to the ZF.
You mentioned harding depth...I would assume with new manufacturing techniques this depth is better controlled thus given the wear surface but keeping a ductile core.
I am not familiar with the klingenberg profile.
Do you know if the work (with explainations) being done will be made public. and the improved ZFs be marketed
You mentioned harding depth...I would assume with new manufacturing techniques this depth is better controlled thus given the wear surface but keeping a ductile core.
I am not familiar with the klingenberg profile.
Do you know if the work (with explainations) being done will be made public. and the improved ZFs be marketed
Yes, the harding depth is the major problem. Back in the days, they can not control the "hardening" so good, so its getting to deep. This lets the bearing failure. I hate this bearing , because the size is terrible: 83 x 46 x 25 mm and they are hard to find .
Peter, that's very interesting.
Please continue to keep us updated on your work on the transmission, including parts availability and prices.
Sounds like a brutal Pantera you guys are working on - any pictures and details?
Please continue to keep us updated on your work on the transmission, including parts availability and prices.
Sounds like a brutal Pantera you guys are working on - any pictures and details?
hi Push, yes we have some crazy people here in Austria :-) But in fact, the last zf , I have rebuild here was from 1972! The ring and pinion, states the date also and it was from 1972!
I think in the near future the ZF "problem " will grow up ! The engines are stronger than in the past and the zf´s are getting older and older.
We have worked out that our new Ring and Pinion have a live time from 32 000 hours @ 141 nm and 4500 rpm. But with 9000 RPM and 700 nm it is dead after only one hour! The function is not linerar - its like a e-function. But our new Ring and Pinion is minimum 1.5 factor better than the stock one!
So you can imagine how long a old ring and pinion set works, when you drive hard with a 700 nm Engine! Maybe a couple of weeks! Friends with racing BMW M1 change every year the ring and pinion sets, because they do not want to have a big zf failure during the race! When you increase the power from the Engine, the zf is realy a weak point. Right now we collect orders for the new ring and pinion sets. The ratio is about 4.0 . price something arround 2500.- and 3000.- euros it depends on the quantity. please pm me, when you are interessed.
I think in the near future the ZF "problem " will grow up ! The engines are stronger than in the past and the zf´s are getting older and older.
We have worked out that our new Ring and Pinion have a live time from 32 000 hours @ 141 nm and 4500 rpm. But with 9000 RPM and 700 nm it is dead after only one hour! The function is not linerar - its like a e-function. But our new Ring and Pinion is minimum 1.5 factor better than the stock one!
So you can imagine how long a old ring and pinion set works, when you drive hard with a 700 nm Engine! Maybe a couple of weeks! Friends with racing BMW M1 change every year the ring and pinion sets, because they do not want to have a big zf failure during the race! When you increase the power from the Engine, the zf is realy a weak point. Right now we collect orders for the new ring and pinion sets. The ratio is about 4.0 . price something arround 2500.- and 3000.- euros it depends on the quantity. please pm me, when you are interessed.