Is this pinion damaged ?
Only to be sure. I do not know it exactly because maybe they built them not so perfect back in the days.
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Looks like cleaned-up rust-pitting. Not quite in the tooth root, but if luck is not on your side and your engine has more than stock horsepower, it's a guess as to whether that will become a broken tooth or not. The Ford/ZF steel is not normally considered weldable, either. You've been trying to decide whether to change ring-and-pinion gear ratios; this is an excellent reason to do so.
Looks like the other tooth in view may have a similar mark, maybe a contact wear pattern from an improperly lashed ring and pinion.
Guy's,
This is what a pinion looks like when its' useful life is coming to an end. This tooth is beginning to break down the surface heat treating performed when new. ALL ZF pinions do this and I've seen many with much more severe a breakdown.
It may last ten years with light use or completely fail next week........ but it will continue to shed material and accelerate the wear of other components, especially all of those needle & roller bearings in the transaxle which do not come cheap besides the labor to get to them.
You can roll the dice or as suggested by Jack, now is the time to decide on another ratio or stock replacement ratio.
Hope this helps ! !
This is what a pinion looks like when its' useful life is coming to an end. This tooth is beginning to break down the surface heat treating performed when new. ALL ZF pinions do this and I've seen many with much more severe a breakdown.
It may last ten years with light use or completely fail next week........ but it will continue to shed material and accelerate the wear of other components, especially all of those needle & roller bearings in the transaxle which do not come cheap besides the labor to get to them.
You can roll the dice or as suggested by Jack, now is the time to decide on another ratio or stock replacement ratio.
Hope this helps ! !
As usual , Les is exactly correct. The condition is known as surface fatigue failure or spalling. The gear will eventually fail but could last for years under light use.
Ron
Ron
Thanks a lot for your answers.
This is what I think Ron.
Does somebody saw a broken pinion ?
I only geard that it will make some noise.
Maybe Patric Hals will also make a statement here. He drives the candy and sold me this zf .
Thanks
Peter
This is what I think Ron.
Does somebody saw a broken pinion ?
I only geard that it will make some noise.
Maybe Patric Hals will also make a statement here. He drives the candy and sold me this zf .
Thanks
Peter
Peter,
This is a prime example of why you should never buy a ZF transaxle unless you've had it checked out by someone who's qualified to offer an opinion as to its condition. That is, unless the potential cost of a major repair was factored into the price or you're willing to take the risk.
Mind you, if it was sold to you as a newly rebuilt ZF, the question that begs to be asked is, in the course of a normal rebuild, should the ring and pinion have been replaced? Was the rebuilder qualified to work on a ZF? If the pinion gear looks like that, what other expensive parts might not have been replaced, that should have been.
Do you have a bill of sale or any written documentation that represents the condition of this ZF as better than what it is? I gather from the tone of your posting that you think you were lied to about the condition prior to purchase.
This is a prime example of why you should never buy a ZF transaxle unless you've had it checked out by someone who's qualified to offer an opinion as to its condition. That is, unless the potential cost of a major repair was factored into the price or you're willing to take the risk.
Mind you, if it was sold to you as a newly rebuilt ZF, the question that begs to be asked is, in the course of a normal rebuild, should the ring and pinion have been replaced? Was the rebuilder qualified to work on a ZF? If the pinion gear looks like that, what other expensive parts might not have been replaced, that should have been.
Do you have a bill of sale or any written documentation that represents the condition of this ZF as better than what it is? I gather from the tone of your posting that you think you were lied to about the condition prior to purchase.
David, thanks for your words.
I bought this zf fresh rebuild.
The seller said that he invest more than 4000 euro !
In fact , right now it is in a specialized company wich works for Zf and they said that there is no part new inside !
Nothing new ! It was only dissambled and glued together with silicon.
The seller do not answer my emails.
Its a verry poor situation.
A new zf from rtb would be cheaper now
I bought this zf fresh rebuild.
The seller said that he invest more than 4000 euro !
In fact , right now it is in a specialized company wich works for Zf and they said that there is no part new inside !
Nothing new ! It was only dissambled and glued together with silicon.
The seller do not answer my emails.
Its a verry poor situation.
A new zf from rtb would be cheaper now
In your current situation I would put it back together and drive it until it fails. I see no point in spending thousands to fix something that isn't broken yet. It may live a happy life. If it fails no problem you were going to spend thousands on a new RBT anyway.
I tend to agree with ItalFord.
What does the wear pattern look like in that area on the ring gear?
I personally would want to see a loading pattern (wear pattern) on the teeth.
It might just be that portion of the gear flaked in that spot OR for some reason developed rust right there?
That COULD be an indication that there is no direct tooth to tooth contact in that spot.
There is no guaranty that a new ring and pinion would not show some kind of a "concern" in spots on the teeth.
I would guess that you would want to do some kind of a surface imaging on both.
Many years ago Chevy was having problems with the 427 steel crankshafts. The hardening process that they went through were showing spider web pattern cracking on the bearing surfaces AFTER they sat on the "shelf" for a period of time.
Chevy removed them under fear that they would fail in competition. I don't remember what the fix was. It MIGHT have been caused by "tough-triding" the cranks?
It's a long time ago and I just don't remember specifically, just generically.
The other thing is that all designs have stress factors in the calculation (a safety factor). It could well be that the gear is already oversized and probably has a 85% (or less) stress loading. Parts are rarely stressed 100%.
Supercharging something like a 427 probably would be the concern here.
What does the wear pattern look like in that area on the ring gear?
I personally would want to see a loading pattern (wear pattern) on the teeth.
It might just be that portion of the gear flaked in that spot OR for some reason developed rust right there?
That COULD be an indication that there is no direct tooth to tooth contact in that spot.
There is no guaranty that a new ring and pinion would not show some kind of a "concern" in spots on the teeth.
I would guess that you would want to do some kind of a surface imaging on both.
Many years ago Chevy was having problems with the 427 steel crankshafts. The hardening process that they went through were showing spider web pattern cracking on the bearing surfaces AFTER they sat on the "shelf" for a period of time.
Chevy removed them under fear that they would fail in competition. I don't remember what the fix was. It MIGHT have been caused by "tough-triding" the cranks?
It's a long time ago and I just don't remember specifically, just generically.
The other thing is that all designs have stress factors in the calculation (a safety factor). It could well be that the gear is already oversized and probably has a 85% (or less) stress loading. Parts are rarely stressed 100%.
Supercharging something like a 427 probably would be the concern here.
The problem with 'using a damaged ZF until it REALLY fails' means constantly being on edge while moving, and if this car is to be a race-clone, failure may well come at high rpms & speeds. I've heard of teeth and other hard objects getting in the ring/pinion mesh under power and the forces involved splitting a ZF's aluminum cases open like a walnut! Not something I'd want to risk on a track or in highway traffic; YMMV.
quote:Originally posted by Bosswrench:...splitting a ZF's aluminum cases open like a walnut!..
would that be a Persian (J.Regai)? since an Eastern Black (J.Nigra) is pretty hard to open
quote:Originally posted by Bosswrench:
The problem with 'using a damaged ZF until it REALLY fails' means constantly being on edge while moving, and if this car is to be a race-clone, failure may well come at high rpms & speeds. I've heard of teeth and other hard objects getting in the ring/pinion mesh under power and the forces involved splitting a ZF's aluminum cases open like a walnut! Not something I'd want to risk on a track or in highway traffic; YMMV.
Isn't that part of the "rush" a driver gets from racing, i.e., they "dodged a bullet" and lived to tell about it?
In a race car, anything at anytime can go wrong at extreme duress?
The problem is : what happens when it fail?
The zf specialist said that I should change it.
He have build some zf for the m1 and this will fail in about 5000 km .
Does someone know what happens when the pinion break ?
Thanks
The zf specialist said that I should change it.
He have build some zf for the m1 and this will fail in about 5000 km .
Does someone know what happens when the pinion break ?
Thanks
Pretty easy, the car stops...
quote:Originally posted by GT4Peter:
The problem is : what happens when it fail?
The zf specialist said that I should change it.
He have build some zf for the m1 and this will fail in about 5000 km .
Does someone know what happens when the pinion break ?
Thanks
I would say, "bada boom, BIG BADA BOOM".
As Boss Wrech said, it will probably destroy the case also, BUT it MIGHT NOT fail. Maybe?
You HAVE TO look at the contact patterns on both the ring and the pinion. That will show you where they make contact. That is the stressed area.
If there is no contact at that "imperfection point" there is no loading on it.
Steel crankshafts get wrecked all the time and a large portion of the time they can be ground down to take the imperfection out.
My concern would be that the hardened surface of the steel could continue to separate itself from the softer layers inside and will act like the grains of wood separating in layers.
Like plywood that gets wet and the layers of the veneers start separating. Super hardened steel can do that also.
The steel won't peel off like wood veneer would but it will flake off probably .015 or .020" deep about the size that you already have with material missing.
The real problem is that at this level you really need to use some kind of an examination system like magnaflux or I think zyglow is similar to look for patterns in the surface of the steel. It will look a lot like glass cracking in a random pattern.
Then those parts become at best paper weights on the work bench. The temper of the metal is just done at that point.
The experts are not wrong. They simply can not tell the nature of the imperfection and presume the worst case scenario.
The cost is relative here. Here you are wagering a $3000 ring and pinion vs. a $12,000 transmission.
I actually discovered a very inexpensive way of checking for cracks purely by accident. You take the real heavy duty wheel cleaner that smells like battery acid and smarts you eyes.
You squirt the stuff on the polished surface of the part you are "cleaning" and let it sit for about 15 minutes.
Then you hose it off with fresh water.
IF there is a crack in the STEEL, (works on iron too) the part will separate right in front of your eyes and create a fisher like we would see in a glacier.
Works every time.
FWIW, be careful of the ZF version made for the BMW M-1. Almost none of the internal bits interchange with a 'std' ZF 5DS-25/2. The shafts have larger ODs, the internal bearings & gears are larger so do not fit and the diff case section is externally changed. Halfshafts used CV joints rather than std U-joints. Supposedly stronger M-1 guts can be fitted to the earlier ZF cases by a skilled machinist, but I've never seen one so done. Again, because the M-1 ZF was a limited semi-racing/production sub-model, few spares exist and almost no one is an 'expert' with that ZF variant. I suspect most have had a far rougher life than the avg. Pantera ZF. Maybe someone at ZF in the Schwaebisch Gmuend Werks could give you more info, if you find one.
Peter Hi
as said befor I can recommend ZF Service in greater Stuttgart area. The tech section is led by a very Senior fellow - a guy with gray hair - he was involved in the development of the Gear box in his junger years in Schwäbisch Gmünd, so my box did cause him a nice smile. He led the rebuild of my box. Manfred Huber..! Well parts came via RBT
=======================0
ZF Friedrichshafen AG, ZF Services Stuttgart
Robert-Bosch-Str.6 73660 Urbach,
Telefon/Phone +49 7181 9800-21, Telefax/Fax +49 7181 9800-50
manfred.huber@zf.com
==========================
Matthias
as said befor I can recommend ZF Service in greater Stuttgart area. The tech section is led by a very Senior fellow - a guy with gray hair - he was involved in the development of the Gear box in his junger years in Schwäbisch Gmünd, so my box did cause him a nice smile. He led the rebuild of my box. Manfred Huber..! Well parts came via RBT
=======================0
ZF Friedrichshafen AG, ZF Services Stuttgart
Robert-Bosch-Str.6 73660 Urbach,
Telefon/Phone +49 7181 9800-21, Telefax/Fax +49 7181 9800-50
manfred.huber@zf.com
==========================
Matthias
quote:Originally posted by Bosswrench:
FWIW, be careful of the ZF version made for the BMW M-1. Almost none of the internal bits interchange with a 'std' ZF 5DS-25/2. The shafts have larger ODs, the internal bearings & gears are larger so do not fit and the diff case section is externally changed. Halfshafts used CV joints rather than std U-joints. Supposedly stronger M-1 guts can be fitted to the earlier ZF cases by a skilled machinist, but I've never seen one so done. Again, because the M-1 ZF was a limited semi-racing/production sub-model, few spares exist and almost no one is an 'expert' with that ZF variant. I suspect most have had a far rougher life than the avg. Pantera ZF. Maybe someone at ZF in the Schwaebisch Gmuend Werks could give you more info, if you find one.
************* Jack, I'm sorry to say you have erroneous information on the ZF used in the M-1 cars. The street box for the M-1 major differences are: Synchro cones will only work with an M-1 gear - the limited slip is the conical disc higher lock up unit- the CV stub axles can be swapped for the standard 1/2 shaft pieces in the Pantera - ALL of the bearings and shafts are the EXACT SAME size as the Pantera type 2 box and the externals of the case have been majorly reenforced along with more bosses for different mounting uses.......that's all.
I've swapped M-1 components (guts) into our cases dozens of times and put our guts into M-1 cases and EVERYTHING fits.
I have also serviced and repaired several "racing M-1" ZF's and all points I have stated above hold true also!!!
Now....... gears, bearings, input shaft, and synchro rings can NOT be mingled between dash-1 & dash-2 ZF's. Here there "ARE" different bearing sizes used on the input shafts, but ALL of the outside bearing diameters are the same where they press into the case.
When it comes to the very early "dash-0" ZF nothing internal is interchangeable between it and dash-1, dash-2, and the M-1 ZF. Way different sizes and lengths of these parts.
Hope this helps clarify this myth regarding the M-1 ZF. *****************
quote:Originally posted by PanteraDoug:
I tend to agree with ItalFord.
What does the wear pattern look like in that area on the ring gear?
I personally would want to see a loading pattern (wear pattern) on the teeth.
It might just be that portion of the gear flaked in that spot OR for some reason developed rust right there?
********* Doug, the gear tooth is beginning to fail at the points you see fracturing and material shedding. There does not need to be direct tooth contact here. As this area continues to shed material the tooth WILL begin to flex more and more until, worst case scenario, it has a catastrophic failure and I do mean catastrophic !!
As I stated in my first post on this, it "may" take some time to reach that point depending on the easy or hard of a life it leads. I he were to decide to leave it in, the teeth should be looked at least once a year to see how fast they are deteriorating. You would be amazed how fast this could go bad....a risk I would never take personally or allow one of my customers to take. It is like playing "Russian Roulette" with your transaxle...*************
That COULD be an indication that there is no direct tooth to tooth contact in that spot.
There is no guaranty that a new ring and pinion would not show some kind of a "concern" in spots on the teeth.
******** The "NEW" ring and pinion will NOT show this indication or concern as it is new! You must remember that this pinion could have been in use for the last 46 years and is finally showing its' age. **********
I would guess that you would want to do some kind of a surface imaging on both.
Many years ago Chevy was having problems with the 427 steel crankshafts. The hardening process that they went through were showing spider web pattern cracking on the bearing surfaces AFTER they sat on the "shelf" for a period of time.
Chevy removed them under fear that they would fail in competition. I don't remember what the fix was. It MIGHT have been caused by "tough-triding" the cranks?
It's a long time ago and I just don't remember specifically, just generically.
The other thing is that all designs have stress factors in the calculation (a safety factor). It could well be that the gear is already oversized and probably has a 85% (or less) stress loading. Parts are rarely stressed 100%.
Supercharging something like a 427 probably would be the concern here.
I am just the suspicious type. New doesn't guaranty anything necessarily to me.
thanks for your answers, the zf specialist also say : when the car have only 100 HP no problem.
But with 500 Hp it will fail. Its only a metter of time :-( BUT : Nobody have seen a broken pinion in a ZF ! I spoke to so much people and all what they say is : a ring and pinion never broke.
Some of them changed a ring and pinion set, when it looks like mine now. But nobody hade a broken one.
So I guess the first " layer" / sorry for my english , I hope you understand the meaning/ is a hard metal. Maybe it is normal that a pinion looks like this after maybe only 5 years ? I know the safty factor in Germany bac in the days was a least 1:2 so the ZF can take more than 900 NM for a while. So maybe those parts will live longer than you think ?
when it realy break, It will break in the 5 gear at full throttle and only the theeth from the pinion. I guess that there is no massive ZF chrash. The broken parts will fall to the side on the bottom from the zf. The Ring and pinion is "allone" in the zf. No other parts are in their way. Maybe it will fail one time , but without Booom and bang ?! :-)
But with 500 Hp it will fail. Its only a metter of time :-( BUT : Nobody have seen a broken pinion in a ZF ! I spoke to so much people and all what they say is : a ring and pinion never broke.
Some of them changed a ring and pinion set, when it looks like mine now. But nobody hade a broken one.
So I guess the first " layer" / sorry for my english , I hope you understand the meaning/ is a hard metal. Maybe it is normal that a pinion looks like this after maybe only 5 years ? I know the safty factor in Germany bac in the days was a least 1:2 so the ZF can take more than 900 NM for a while. So maybe those parts will live longer than you think ?
when it realy break, It will break in the 5 gear at full throttle and only the theeth from the pinion. I guess that there is no massive ZF chrash. The broken parts will fall to the side on the bottom from the zf. The Ring and pinion is "allone" in the zf. No other parts are in their way. Maybe it will fail one time , but without Booom and bang ?! :-)
quote:Originally posted by GT4Peter:
thanks for your answers, the zf specialist also say : when the car have only 100 HP no problem.
But with 500 Hp it will fail. Its only a metter of time :-( BUT : Nobody have seen a broken pinion in a ZF ! I spoke to so much people and all what they say is : a ring and pinion never broke.
Some of them changed a ring and pinion set, when it looks like mine now. But nobody hade a broken one.
So I guess the first " layer" / sorry for my english , I hope you understand the meaning/ is a hard metal. Maybe it is normal that a pinion looks like this after maybe only 5 years ? I know the safty factor in Germany bac in the days was a least 1:2 so the ZF can take more than 900 NM for a while. So maybe those parts will live longer than you think ?
when it realy break, It will break in the 5 gear at full throttle and only the theeth from the pinion. I guess that there is no massive ZF chrash. The broken parts will fall to the side on the bottom from the zf. The Ring and pinion is "allone" in the zf. No other parts are in their way. Maybe it will fail one time , but without Booom and bang ?! :-)
Is this betting time? Who holds the money?
My bet is that the nature of the failure will be, the top super hardened outer layer will flake on the contact patch.
It will cause a strange vibration in the transmission. It will get disassembled and replaced.
That's my bet.
You are making an assumption that if a tooth broke off of the pinion in a chunk, that it would fall to the bottom and not interfere with the operation.
What happens if the heat that causes the failure causes the piece of tooth of the pinion to stick to the ring gear?
That's called friction welding.
That was BossWrench's vision of the failure.
In that scenario, bada boom. Me? I'm not betting on that one at all. Odds are very bad on it but some times a 50 to 1 wins?
quote:Originally posted by GT4Peter:
thanks for your answers, the zf specialist also say : when the car have only 100 HP no problem.
But with 500 Hp it will fail. Its only a metter of time :-( BUT : Nobody have seen a broken pinion in a ZF ! I spoke to so much people and all what they say is : a ring and pinion never broke.
Some of them changed a ring and pinion set, when it looks like mine now. But nobody hade a broken one.
So I guess the first " layer" / sorry for my english , I hope you understand the meaning/ is a hard metal. Maybe it is normal that a pinion looks like this after maybe only 5 years ? I know the safty factor in Germany bac in the days was a least 1:2 so the ZF can take more than 900 NM for a while. So maybe those parts will live longer than you think ?
when it realy break, It will break in the 5 gear at full throttle and only the theeth from the pinion. I guess that there is no massive ZF chrash. The broken parts will fall to the side on the bottom from the zf. The Ring and pinion is "allone" in the zf. No other parts are in their way. Maybe it will fail one time , but without Booom and bang ?! :-)
The ZF pinions DO BREAK........... I have several broken pinions which. (if I can find them) gladly show you pictures of. Trust me the do break - fail and when it happens it is usually terminal for the entire transaxle.