Warranty battles over T5 gearbox
Discussion
I'm currently in a dispute with my warranty company over repairs to 5th gear on my Chimaera. Their engineers are claiming damage was the result of material from reverse gear broken off due to selecting reverse while in forward motion.
Needless to say I'm disputing the issue and have tried pointing out that damage apparent on the reverse gear is due to grinding that occurs when attempting to select reverse on the T5 gearbox. Normal solution being to pre-select 3rd or 5th. I have supplied them with references to Steve Heath's book and a buyer's guide on ChimaeraPages, both of which mention the feature. However as far as they are concerned TVR has never reported it as a defect so it is a fault I should have had fixed by the garage when I bought it.
Does anyone know of any references to this feature of the gearbox in any other publications or whether TVR's own workshop manuals mention it?
If I'm going to have to take this to court I'm going to need to prove that this is a feature of the gearbox and not something I should have had fixed when I bought it.
Cheers
Andy....
Needless to say I'm disputing the issue and have tried pointing out that damage apparent on the reverse gear is due to grinding that occurs when attempting to select reverse on the T5 gearbox. Normal solution being to pre-select 3rd or 5th. I have supplied them with references to Steve Heath's book and a buyer's guide on ChimaeraPages, both of which mention the feature. However as far as they are concerned TVR has never reported it as a defect so it is a fault I should have had fixed by the garage when I bought it.
Does anyone know of any references to this feature of the gearbox in any other publications or whether TVR's own workshop manuals mention it?
If I'm going to have to take this to court I'm going to need to prove that this is a feature of the gearbox and not something I should have had fixed when I bought it.
Cheers
Andy....
NHyde said:
Check the Cerbera forum , I am firmly of the opinion that pre selecting other gears is b****x, patience is the watchword!!
Why? Sticking it into 4th with the clutch pedal pressed stops the gears rotating, so if you then quickly slot it into reverse it avoids the crunching. Mars said:
NHyde said:
Check the Cerbera forum , I am firmly of the opinion that pre selecting other gears is b****x, patience is the watchword!!
Why? Sticking it into 4th with the clutch pedal pressed stops the gears rotating, so if you then quickly slot it into reverse it avoids the crunching. 
almost every time. Same with the old LT77 in my Wedges.Because I followed that procedure ,.........and then had a 5th gear failure on the M5 . I had several experts on here telling me that my problem was a broken drive shaft , and two independents said the same thing, until one of those looked at the car and said "Oh s**t" you were right !!
Subsequently , several other Cerbera owners had 5th gear failure.
Pays your money , takes your choice, but a little patience by easing in to reverse surely cannot do any harm.
Subsequently , several other Cerbera owners had 5th gear failure.
Pays your money , takes your choice, but a little patience by easing in to reverse surely cannot do any harm.
Unfortunately patience has nothing to do with it. There is enough drag from the "open" clutch to keep the gearbox spinning unless you stop it. Reverse doesn't have a syncro, so it crunches unless you stop it spinning. It's just the way it is in the Cerb.
Actually, it's the way the only Sierra Cosworth I've ever driven was too. I'll ask my kit-car-owning friends too. Some of them have Cosworth turbo engines mated to T5s.
Anyway, I'm slightly bemused by your belief that this technique can damage a 5th gear. What mode of failure are we talking about. Gear teeth lost? Dog teeth lost? Baulk rings damaged? In all cases I can only point to the normal operation of the gearbox - that being when you change up from 4th - as being harder on the box than dropping it into a gear to stop the box at idle.
Regardless, my preference is to drop it into 4th. As there isn't actually a 4th gear in a T5 (it's the 1:1 ratio which is just a shaft-lockup) there are no gear teeth to damage. That's not the reason I do it though ("did" it - sold the Cerb a few weeks back). It is just easier to go from 4th to reverse than from 5th to reverse.
Actually, it's the way the only Sierra Cosworth I've ever driven was too. I'll ask my kit-car-owning friends too. Some of them have Cosworth turbo engines mated to T5s.
Anyway, I'm slightly bemused by your belief that this technique can damage a 5th gear. What mode of failure are we talking about. Gear teeth lost? Dog teeth lost? Baulk rings damaged? In all cases I can only point to the normal operation of the gearbox - that being when you change up from 4th - as being harder on the box than dropping it into a gear to stop the box at idle.
Regardless, my preference is to drop it into 4th. As there isn't actually a 4th gear in a T5 (it's the 1:1 ratio which is just a shaft-lockup) there are no gear teeth to damage. That's not the reason I do it though ("did" it - sold the Cerb a few weeks back). It is just easier to go from 4th to reverse than from 5th to reverse.
The problem with 5th gear on the T5 is that it was a bit of an afterthought and is the weakest forward gear of the all. It can slip down its shaft, break/loose its key and thus loose drive although there are some well documented fixes for that. It can sheer teeth as well as the teeth profile is not as strong as it could be. So my first question would be: what was broken in the gearbox that caused 5th gear to fail? Was it the shaft key, the gear teeth or what?
The reverse clunk is due to a no synchromesh and selecting another gear aligns the gears, stops the clutch spinning and gives reverse a better chance of surviving.
The crunch can be made worse depending on which oil is used and the operating temperature.
If you want the real experts try CTS www.gearboxman.com
The reverse clunk is due to a no synchromesh and selecting another gear aligns the gears, stops the clutch spinning and gives reverse a better chance of surviving.
The crunch can be made worse depending on which oil is used and the operating temperature.
If you want the real experts try CTS www.gearboxman.com
Edited by shpub on Tuesday 4th March 22:04
Can't be bothered to search for other threads , but here is one.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There was no other failure in my box other than fatigue of the 5th gear
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There was no other failure in my box other than fatigue of the 5th gear
Edited by NHyde on Tuesday 4th March 22:12
shpub said:
The problem with 5th gear on the T5 is that it was a bit of an afterthought and is the weakest forward gear of the all. It can slip down its shaft, break/loose its key and thus loose drive although there are some well documented fixes for that. It can sheer teeth as well as the teeth profile is not as strong as it could be. So my first question would be: what was broken in the gearbox that caused 5th gear to fail? Was it the shaft key, the gear teeth or what?
The reverse clunk is due to a no synchromesh and selecting another gear aligns the gears, stops the clutch spinning and gives reverse a better chance of surviving.
The crunch can be made worse depending on which oil is used and the operating temperature.
If you want the real experts try CTS www.gearboxman.com
According to the warranty company's engineers they found damage on the reverse gear 'consistent' with selecting reverse gear while in motion. They thus conclude that material from the reverse gear caused damage to the 5th gear set. My claim was for repairs to failed syncro on 5th, they rejected it claiming I caused the damage through selecting reverse while in motion. I'm trying to find evidence that the damage seen on the reverse gear set (which is nothing to do with the claim) is normal for these gearboxs and nothing to do with my driving technique. To date the engineers have refused to accept that the gearbox grinds when selecting reverse.The reverse clunk is due to a no synchromesh and selecting another gear aligns the gears, stops the clutch spinning and gives reverse a better chance of surviving.
The crunch can be made worse depending on which oil is used and the operating temperature.
If you want the real experts try CTS www.gearboxman.com
Edited by shpub on Tuesday 4th March 22:04
I'll give gearboxman a go.
Cheers
Andy....
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