Gearbox failed after rebuild - my fault?
Discussion
Last year I experienced a gearbox failure requiring a stripdown and rebuild. My car requires 35 hours of labour to remove and replace the gearbox (the engine must come out). And that’s before the cost of the rebuild itself.
Shortly after collecting the car post gearbox rebuild in March, I started to notice an issue with the box coming out of 3rd gear by itself. It only happened occasionally and as this is a weekend car that gets used infrequently, the car was given the benefit of the doubt.
Six months after the rebuild I finally brought the car to the specialist who did the work (a 200 mile round trip). After road-testing the car they could not replicate the issue and gave it a clean bill of health.
It was apparent that the issue was there however, and getting worse. Finally in December I returned to the specialist and was able to replicate the problem myself on an accompanied test drive.
After leaving the car with them for inspection they have opened the box for a second time and found damage to a synchro and baulk ring. They have said this cannot be related to the rebuild and that it is in fact due to my overly enthusiastic gear-changing style (as apparently evidenced by the technician observing me during the test drive). And while a small amount of goodwill has been offered, I’m responsible for paying a sizeable sum for a second major repair, less than 12 months and 4,000 miles after the first.
In 31 years of driving I’ve never damaged a synchromesh before. I habitually H+T on every downshift and in fact as never as much as worn out a clutch. Does it seem plausible that I could have done enough damage through bad gearchanging habits to destroy a synchro on a modern gearbox after less than 4,000 miles?
Shortly after collecting the car post gearbox rebuild in March, I started to notice an issue with the box coming out of 3rd gear by itself. It only happened occasionally and as this is a weekend car that gets used infrequently, the car was given the benefit of the doubt.
Six months after the rebuild I finally brought the car to the specialist who did the work (a 200 mile round trip). After road-testing the car they could not replicate the issue and gave it a clean bill of health.
It was apparent that the issue was there however, and getting worse. Finally in December I returned to the specialist and was able to replicate the problem myself on an accompanied test drive.
After leaving the car with them for inspection they have opened the box for a second time and found damage to a synchro and baulk ring. They have said this cannot be related to the rebuild and that it is in fact due to my overly enthusiastic gear-changing style (as apparently evidenced by the technician observing me during the test drive). And while a small amount of goodwill has been offered, I’m responsible for paying a sizeable sum for a second major repair, less than 12 months and 4,000 miles after the first.
In 31 years of driving I’ve never damaged a synchromesh before. I habitually H+T on every downshift and in fact as never as much as worn out a clutch. Does it seem plausible that I could have done enough damage through bad gearchanging habits to destroy a synchro on a modern gearbox after less than 4,000 miles?
Are we talking a Fiat 500 or a Nissan Skyline GTR running 850HP?
It’s possible you could have worn it out, or the garage have used knock off parts or old / used parts rather than new, or the parts were defective ...
No warranty on the work completed?
given the fact you raised the issue between the rebuild and today, I assume today is 4000 miles completed, how many had you done the first time it went back?
It’s possible you could have worn it out, or the garage have used knock off parts or old / used parts rather than new, or the parts were defective ...
No warranty on the work completed?
given the fact you raised the issue between the rebuild and today, I assume today is 4000 miles completed, how many had you done the first time it went back?
H+T does nothing to reduce stress/ load/ wear on the synchro rings (all it does is reduce wear on the clutch and make things smoother). To reduce wear on the synchro rings you need to double-de-clutch, which can of course be combined with H+T
I would image however, that someone who has the understanding and ability to H+T / rev match has somewhat of a mechanically sympathetic driving style.
I’d suggest that unless you totally abuse the gearbox, very fast harsh gear changes, slamming it into gear - you haven’t caused the issue yourself.
I would image however, that someone who has the understanding and ability to H+T / rev match has somewhat of a mechanically sympathetic driving style.
I’d suggest that unless you totally abuse the gearbox, very fast harsh gear changes, slamming it into gear - you haven’t caused the issue yourself.
Lord.Vader said:
Are we talking a Fiat 500 or a Nissan Skyline GTR running 850HP?
It’s possible you could have worn it out, or the garage have used knock off parts or old / used parts rather than new, or the parts were defective ...
No warranty on the work completed?
given the fact you raised the issue between the rebuild and today, I assume today is 4000 miles completed, how many had you done the first time it went back?
The specialist is saying the damage is unrelated to the rebuild and only have been caused by driver error.It’s possible you could have worn it out, or the garage have used knock off parts or old / used parts rather than new, or the parts were defective ...
No warranty on the work completed?
given the fact you raised the issue between the rebuild and today, I assume today is 4000 miles completed, how many had you done the first time it went back?
From memory car had done approx 2k miles first time it went back - no official record though.
mph999 said:
H+T does nothing to reduce stress/ load/ wear on the synchro rings (all it does is reduce wear on the clutch and make things smoother). To reduce wear on the synchro rings you need to double-de-clutch, which can of course be combined with H+T
I would image however, that someone who has the understanding and ability to H+T / rev match has somewhat of a mechanically sympathetic driving style.
I’d suggest that unless you totally abuse the gearbox, very fast harsh gear changes, slamming it into gear - you haven’t caused the issue yourself.
Thanks - I naturally take that view myself, particularly as I had no problems for the first two years and 10k miles of ownership only to be informed that I had abused the gearbox enough to break a synchro in less than half that amount of time and miles following a total rebuild.I would image however, that someone who has the understanding and ability to H+T / rev match has somewhat of a mechanically sympathetic driving style.
I’d suggest that unless you totally abuse the gearbox, very fast harsh gear changes, slamming it into gear - you haven’t caused the issue yourself.
What I’m trying to figure out is whether I might have a case to bring in claims court, or whether I chalk it up to experience and pay up again for a second major bill in two years, pushing my spend on this gearbox into five figures.
Has it got a quick shifter on it.
I know some guys who added qucikshifters to some lotuses had massive issues with lunching their boxes. The tuners who sold and fitted them did not want to know, of course.
A modern car should do 100k without any serious gearbox problems in my experience, yes, some bearing whine may occur, some vws have weak bearings or diff cages, but still will make 100k miles.
As for being unconnected with the rebuild.....are they honestly saying you’ve lunched brand new synchros is a coupe of thou miles? That’s b
ks, unless the fitted them wrong.
So if they say, they weren’t brand new, they were the old ones, ask them why they refitted fked syncros?
I know some guys who added qucikshifters to some lotuses had massive issues with lunching their boxes. The tuners who sold and fitted them did not want to know, of course.
A modern car should do 100k without any serious gearbox problems in my experience, yes, some bearing whine may occur, some vws have weak bearings or diff cages, but still will make 100k miles.
As for being unconnected with the rebuild.....are they honestly saying you’ve lunched brand new synchros is a coupe of thou miles? That’s b
ks, unless the fitted them wrong. So if they say, they weren’t brand new, they were the old ones, ask them why they refitted f
ked syncros? Standard gear shift. According to the specialist, the boxes don’t like being rushed and I have an unusually aggressive shifting style. Still can’t see how I could have destroyed a synchro so quickly unless I was deliberately trying to. They say all parts were meticulously inspected and signed off for installation during the rebuild, therefore it could only be me that caused it.
Boosted LS1 said:
As an aside, do you rest your hand on the gearstick?
Not that I’m aware of. In fact I always thought I was reasonably mechanically sympathetic. I have no fear of people pointing out things that challenge my view of myself, but it just seems too coincidental that this could have happened so soon after an expensive rebuild when I had no problems for the first two years with this car, nor during the 30+ years I’ve been driving.Gearbox jumping out of (3rd) gear is a sign of a worn or defective 3rd/4th hub and/or defects in the dog teeth of third gear. (As long as there isn't excessive endfloat anywhere. A completely separate issue to the synchro ring.
In order for a synchro ring to work properly, the ring itself must be in good order and the hub springs not broken or weak.
Slamming it through gears will wear out the synchro ring, and could cause damage to the dog teeth, but I can't see how this would cause jumping out of gear. Such wear would be on the front of the dog teeth, not the backcut part that holds it in gear.
I smell bulls
t. caziques said:
In order for a synchro ring to work properly, the ring itself must be in good order and the hub springs not broken or weak.
Thank you. I have been shown photos of a synchro ring (4th, not 3rd) with teeth ground off, and excessive wear also to the baulk ring. I am trying to understand how it could be possible that I inflicted such damage in a short space of time.plenty said:
Thank you. I have been shown photos of a synchro ring (4th, not 3rd) with teeth ground off, and excessive wear also to the baulk ring. I am trying to understand how it could be possible that I inflicted such damage in a short space of time.
But with such damage to the synchro (which as others have said won't make it jump out of gear) you'd notice it on the gearchange into that gear.Have you asked them how the damage they have noted causes the symptoms you have had?
But as far as options go, you'll be hard pushed to make anything stick in court without a lot of effort and cost of independent inspections.
Bert
paintman said:
Makes you wonder which parts were renewed & which parts were reused during the rebuild.
All synchros and baulk rings were re-used, including the parts which subsequently failed. New parts included gearsets (the cause of the first failure which triggered the rebuild) and main input shaft.The specialist maintains that the re-used parts were in good order and that damage was inflicted after the rebuild.
I've just had a gearbox rebuilt after 1600 miles. Last rebuild we did ourselves with 5 new baulk rings and 4 gears needed replacing, when i say we, it was mainly my friend who runs a specialist garage and me helping. Not long after the build 2nd gear got very crunchy so this time round I enlisted the help of a specialist of these gearboxes (they are pretty rare things).
Straight away they suggested if i didnt renew the engagement sleeve i.e. the ring with the teeth on that engages with the gear, and the baulk ring in the middle, then that would most likely be the cause. I said when inspected it looked perfect and they said that is often the case but a new baulk ring may not take to a used engagement sleeve.
Long story short its all fair and well that they said everything looked in fine condition but it may not have been but in their defense, where do they stop replacing the parts before its basically just a new gearbox. Are they a specialist in the type of car/ drivetrain?
Straight away they suggested if i didnt renew the engagement sleeve i.e. the ring with the teeth on that engages with the gear, and the baulk ring in the middle, then that would most likely be the cause. I said when inspected it looked perfect and they said that is often the case but a new baulk ring may not take to a used engagement sleeve.
Long story short its all fair and well that they said everything looked in fine condition but it may not have been but in their defense, where do they stop replacing the parts before its basically just a new gearbox. Are they a specialist in the type of car/ drivetrain?
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