Vixen 2500 - gear change problem
Discussion
Suddenly got a problem changing gear in my 71, 2500 Vixen fitted with Triumph gearbox and ‘A’ type overdrive unit.
Problem going from 3rd to 2nd as I approached a roundabout and then realised that I could not find any gears – at least for a few seconds until finally got back into third and carried on.
Continued the journey and found all gears difficult to get, but esp first at junctions. Assumed clutch may not be fully disengaging.
Checked clutch slave and rod and I have a good inch or more rod movement. Bled system – no air and no apparent issue. I seem to have clutch action and disengagement eg. in gear on sloping driveway car rolls back quickly when clutch depressed.
Went for another test drive after bleeding clutch system. Got reverse off drive, got first but could not get second. Found reverse – turned round – back on drive.
Bah ! lets give it another go.
Next attempt more successful – out of village got through gears and up into 4th – on slowing down got 3rd but could not get second.
Stopped – found 1st gear but 2nd difficult to locate – but managed to drive off.
Next junction found it difficult to get 1st – but did eventually.
Homeward bound could not get from 3rd to 2nd around tight corner
Back on drive stationary all gears difficult to locate.
Checked gear lever – spring and plunger ok. Loosen adjuster pins.
Another test drive – could not get into second gear. Abandon test drive. Found reverse – then first and back on driveway.
No previous issue with gearbox or overdrive.
Recon gearbox and OD unit – 1500 miles done
New clutch master cylinder/pipe/slave cylinder – no leaks and good action.
Clutch cover was the only part not renewed.
Any suggestions ?
Problem going from 3rd to 2nd as I approached a roundabout and then realised that I could not find any gears – at least for a few seconds until finally got back into third and carried on.
Continued the journey and found all gears difficult to get, but esp first at junctions. Assumed clutch may not be fully disengaging.
Checked clutch slave and rod and I have a good inch or more rod movement. Bled system – no air and no apparent issue. I seem to have clutch action and disengagement eg. in gear on sloping driveway car rolls back quickly when clutch depressed.
Went for another test drive after bleeding clutch system. Got reverse off drive, got first but could not get second. Found reverse – turned round – back on drive.
Bah ! lets give it another go.
Next attempt more successful – out of village got through gears and up into 4th – on slowing down got 3rd but could not get second.
Stopped – found 1st gear but 2nd difficult to locate – but managed to drive off.
Next junction found it difficult to get 1st – but did eventually.
Homeward bound could not get from 3rd to 2nd around tight corner
Back on drive stationary all gears difficult to locate.
Checked gear lever – spring and plunger ok. Loosen adjuster pins.
Another test drive – could not get into second gear. Abandon test drive. Found reverse – then first and back on driveway.
No previous issue with gearbox or overdrive.
Recon gearbox and OD unit – 1500 miles done
New clutch master cylinder/pipe/slave cylinder – no leaks and good action.
Clutch cover was the only part not renewed.
Any suggestions ?
Suggest you post on the Triumph forum.
However, l believe some Triumph 'boxes have the gear clusters held in position with circlips that occasionally come off allowing the clusters to slide back and forth - not sure if your 'box would suffer from this, l had a similar problem with a Spitfire 'box.
Since you say it was an instant problem it sounds like something has come off or broken. You should also contact the supplier if it's only done 1500 miles.
Good luck.
However, l believe some Triumph 'boxes have the gear clusters held in position with circlips that occasionally come off allowing the clusters to slide back and forth - not sure if your 'box would suffer from this, l had a similar problem with a Spitfire 'box.
Since you say it was an instant problem it sounds like something has come off or broken. You should also contact the supplier if it's only done 1500 miles.
Good luck.
Edited by ATE399J on Wednesday 22 July 20:55
By the way you describe the problem, it looks like it is in the shifter rods, the gear selector for the first and second gear is hold in place with a pointed screw to the selector rod this is the same for the reverse gear, the one for third and fourth is solid.
If the these screws are not tight properly these is a change that they will come loose and you will experience more or less the shift problems you describe.
You can check this from under the car, the fact that you have a OD makes it a bit more difficult to check, make sure that there is someone in the car to operate the shifter and that way you can check if the shifter rods are moving at the same time, the screws are external, with a bit of luck you can tight them, that of course if this is the problem.
Good luck.
If the these screws are not tight properly these is a change that they will come loose and you will experience more or less the shift problems you describe.
You can check this from under the car, the fact that you have a OD makes it a bit more difficult to check, make sure that there is someone in the car to operate the shifter and that way you can check if the shifter rods are moving at the same time, the screws are external, with a bit of luck you can tight them, that of course if this is the problem.
Good luck.
If someone with a TR6 asked me this I would say it was clutch "related" as you did mention you felt the clutch was not fully disengaging.
The issue with triumph TR type gearboxes is that there are several points of failure where small amounts of wear at each point add up to engagement/disengagement issues.
Briefly those are.
Cross shaft bushes
Cross shaft fork retaining pin (a particular favorite of mine as new ones appear to be made of cheese)
Fork pins (the pins that sit in the slot on the release bearing and move that bearing in and out
Wear in the engine thrust washers which allow excess crankshaft end float
And now my real favorite the 3 rivet clutch plate which warps just before it disintegrates usually around 12-15oo miles. TR parts resellers used to sell an AP/Magellan engineering clutch plate that only had 3 rivits holding the spline section to the grip section and they always failed. there was a bit thread 14k views I recall about it on the tr register a few years back. That one is a long shot as TR owners know what to look for in a new clutch.
Overall slight wear in all those parts do add up but the fix is inexpensive but the box has to come out.
I hope it is something simple, good luck and I will look out for your updates.
The issue with triumph TR type gearboxes is that there are several points of failure where small amounts of wear at each point add up to engagement/disengagement issues.
Briefly those are.
Cross shaft bushes
Cross shaft fork retaining pin (a particular favorite of mine as new ones appear to be made of cheese)
Fork pins (the pins that sit in the slot on the release bearing and move that bearing in and out
Wear in the engine thrust washers which allow excess crankshaft end float
And now my real favorite the 3 rivet clutch plate which warps just before it disintegrates usually around 12-15oo miles. TR parts resellers used to sell an AP/Magellan engineering clutch plate that only had 3 rivits holding the spline section to the grip section and they always failed. there was a bit thread 14k views I recall about it on the tr register a few years back. That one is a long shot as TR owners know what to look for in a new clutch.
Overall slight wear in all those parts do add up but the fix is inexpensive but the box has to come out.
I hope it is something simple, good luck and I will look out for your updates.
Thanks for the advice. Have done some more testing and to sum up the latest is:
Gear selection is fine with engine not running.
Gear selection is almost fine with engine running on tick over – but second is sometimes difficult.
External clutch operating parts seems fine, ie Lever arm starting position vertical and then good movement on slave push rod to move lever arm.
With rear wheels jacked up off ground clutch disengagement checked and there appears to be plenty of it, and no drag.
Cannot detect crankshaft end float.
Gear oil changed and no nasty bits seen.
My last test drive found one consistent scenario:
Third a bit sticky to get out of and then rarely possible to get down into second but can get back into third, or clutch down, virtually stop the car, select first and then you can go up into second, third and into fourth.
Occasionally when third to second is actually achieved there can be gnashing of gear teeth.
Methinks that the gearbox will have to come out and hopefully the problem will be seen, be box related eg synchromesh, selector forks or even a clutch related issue.
Gear selection is fine with engine not running.
Gear selection is almost fine with engine running on tick over – but second is sometimes difficult.
External clutch operating parts seems fine, ie Lever arm starting position vertical and then good movement on slave push rod to move lever arm.
With rear wheels jacked up off ground clutch disengagement checked and there appears to be plenty of it, and no drag.
Cannot detect crankshaft end float.
Gear oil changed and no nasty bits seen.
My last test drive found one consistent scenario:
Third a bit sticky to get out of and then rarely possible to get down into second but can get back into third, or clutch down, virtually stop the car, select first and then you can go up into second, third and into fourth.
Occasionally when third to second is actually achieved there can be gnashing of gear teeth.
Methinks that the gearbox will have to come out and hopefully the problem will be seen, be box related eg synchromesh, selector forks or even a clutch related issue.
After being side tracked onto easier and more productive projects I have finally got back to the Vixen 2500 and removed the engine and gearbox.
The gearshift problem seems to lay with the shafts in the top cover and the interlock mechanism. Comparing with another Triumph gearbox top cover for which all selector rod movements are smooth with an obvious feel of the ball bearings dropping into their detent, my troublesome top cover is stiff, or just non-compliant especially on one/two and reverse.
Will have to dismantle and inspect but first I have to get those tapered wedglock screws out of the selector forks/shafts. They are very tight !
The gearshift problem seems to lay with the shafts in the top cover and the interlock mechanism. Comparing with another Triumph gearbox top cover for which all selector rod movements are smooth with an obvious feel of the ball bearings dropping into their detent, my troublesome top cover is stiff, or just non-compliant especially on one/two and reverse.
Will have to dismantle and inspect but first I have to get those tapered wedglock screws out of the selector forks/shafts. They are very tight !
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