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TR5/TR250 tranny woes

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J

jdavis

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This is the wrong tine of the year to have a problem! I can't get the transmission into gear. I started having trouble with shifting into 2nd on the way home from TRIALS last year. I presumed the synchro was going bad, and as long as I was slow to shift, I didn't grind too much. But, in the past month, the grinding became more of a problem, now, gradually, I can't get into 1st, or 4th. Interesting, 3d and reverse are not a problem. I presumed that I had a hydraulic problem, but the master and slave check out ok with no significant leak, and I have about 0.5" of shaft mvt. on the slave cylinder in the center hole. The clutch has about 30K on all components (Roadster Factory "magic clutch", and the cross shaft is drilled with a grade 8 bolt in addition to a secured taper pin. The fluid level in the tranny is full. When I can get it into gear, there are no unusual noises at road speed. I have noticed in the past 3000 miles or so, an occ rubbing sound that seems to come from the output of the tranny. The U joint looks good. I checked the tranny fluid, and there are no big chunks of metal. The OD works fine. In neutral, with the engine idling, when I let the clutch out, about 1/2 through the travel, there seems to be an intermittent "clunk" as if there is slack in the drive train. This is intermittent . The clutch feels fine and engages/disengages normally....when I can get the car in gear. Again, with the engine idling, or turned off, the only gear I can get into is third and reverse. Any ideas? Clutch failure, fork failure? Is the tranny about to die?
Joe
 
That has all the signs of a clutch not disengaging all the way. I would bleed the line and then check the linkage adjustment first, as the easiest thing to do. Check both at the slave...and the MC, if it has one on your year. I doubt it is the actual clutch...so that would be the last thing to check. In between, the MC or Slave may be getting a bad seal and not giving fuel travel.
 
thanks for the advice. The car is a TR6. I bled the system and I'm afraid there was not much improvement. Occasionally, the shifting almost seems normal. In neutral, If I pump the clutch 5-6 times, the "clunk" stops and I can get it into gear and shift once or twice, then it is stuck again....THe rod on the slave does move the 0.5" it needs to disengage. But the clutch does feel like it is somehow sticking
Joe
 
Old....I'm about to order from Moss. Hopefully this will solve the problem. THough, given the normal travel of the slave cylinder rod, I doubt it.
 
Hydraulic issues are easier than taking apart transmissions, but if it goes into reverse without grinding I would guess the whole clutch release system is working fine. First sign of partially or non releasing clutch is crunching into reverse or a non-synchro first gear.
 
Further symptoms of my transmission problem for those interested: With the transmission in neutral, I turn the key and the car creeps forward. If I rev the engine it seems to break loose, and i can sort of get into gear, but not without a lot of difficulty. If I do get it into first, I can struggle to drive it ; 1st, 2nd, 3d 4th and reverse along with OD work, but it is very hard to get into gear. cruising down the road everything seems fine as long as I don't try to change gears, although sometimes, especially 3d to 4th, feel fine. The car rolls freely until I come to a stop and turn off the engine. Then when in neutral, the car is stuck again, I can't push the car. It is stuck. In neutral again, using the starter, the var moves forward until I "break it loose" by revving the engine in neutral with my foot on the brake. At this point, in neutral if I pump the clutch there is an awful clanging in the drive train as the clutch is not disengaging right. Once I pump it a few times and rev the engine it feels normal. What is going on?
 
Is the bracket that the slave cylinder mounts to nice and snug?
 
Everything you describe still sounds like clutch...except it moving in neutral. I can think of no way that is possible. Maybe a shift fork is loose, so the tranny is hitting more than one gear? But even if it is, pushing the clutch would release it from the engine and prevent rolling forward under some power.

If the clutch is not releasing all the way, you are damaging the synchros by driving it. For that matter, if it is a tranny issue you are still causing further damage driving it. If you want to play with it, I would recommend lifting the rear wheels to remove load from the drivetrain and prevent further damage. The more I think, if you are jamming the synchros trying to fight a bad clutch, you could have welded a synchro to a gear, causing the creeping.

My money is still on the hydraulics. I still think 1/2” travel is very short for the slave cylinder travel. I would concentrate on that. If it turns out not to be, you are going to have to pull the tranny. There is nothing else serviceable without pulling it.

In any event...I highly recommend NOT driving it until you sort it out. You may ruin the clutch and tranny for a simple hydraulic seal failure.
 
CJD said:
Everything you describe still sounds like clutch...except it moving in neutral. I can think of no way that is possible. Maybe a shift fork is loose, so the tranny is hitting more than one gear? But even if it is, pushing the clutch would release it from the engine and prevent rolling forward under some power.

If the clutch is not releasing all the way, you are damaging the synchros by driving it. For that matter, if it is a tranny issue you are still causing further damage driving it. If you want to play with it, I would recommend lifting the rear wheels to remove load from the drivetrain and prevent further damage. The more I think, if you are jamming the synchros trying to fight a bad clutch, you could have welded a synchro to a gear, causing the creeping.

My money is still on the hydraulics. I still think 1/2” travel is very short for the slave cylinder travel. I would concentrate on that. If it turns out not to be, you are going to have to pull the tranny. There is nothing else serviceable without pulling it.

In any event...I highly recommend NOT driving it until you sort it out. You may ruin the clutch and tranny for a simple hydraulic seal failure.
Click to expand...


Good advice! the car is parked, waiting for some new hydraulic parts
 
I IMHO the pumping off the pedal made the system extend to where maybe the clutch ears where forced in and rubbed, making the nose you heard. Someone posted a similar problem a while back. If you did not have a return spring, again IMHO that would contribute to the extend clutch throw. If you have a Girling system, get the spring from TRF because they sell a Girling spring. IMHO if you use the early spring or the one Moss sells, the spring is too short and to strong and at some point turns into a steal rod and will not let the clutch function. no idea about the neutral thing.
 
Long shot here.
Pilot bushing seized onto transmission input shaft?

M.
 
Merlin63Tr4 said:
Long shot here.
Pilot bushing seized onto transmission input shaft?

M.
Click to expand...

Interesting. I've never seen that happen but it would account for most of the symptoms.
Tom
 
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