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TC Gearbox jumps out of gear

Posted: Mon Mar 04, 2002 1:09 am
by i.thomson@talk21.com
Peter, my Tc gearbox also jumps out of 3rd. on overrun - but i've got used to it and put my knee against it! During the rebuild I stripped the box to look for the reason and found that there were only two of the four synchro balls and springs on third. It must have been assembled like that as there is nowhere for them to go. Unfortunately replacing them made no difference so I live with it as a "feature" of the car. Ian Thomson. ----------------
>But I recall just recently someone stating that Redline is too good for the >TC trans. I guess it had something to do with the syncro rings not getting >a grip on their job. I have not experienced that problem, but my third gear >likes to go AWOL when not under a little torque. Some day I'd like to fix >that but fear I won't know what to look for.
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Re: TC Gearbox jumps out of gear

Posted: Mon Mar 04, 2002 4:43 am
by Robert Grunau
My TC-8654 EXU also used to just sneak out of third on a light overrun. When I stripped the box the third gear locate bolt on the fork was loose and broken. I hope that was the problem. I have just installed Redline 75-90 NS ( 75-140NS on order ) gear oil so I hope it works well. Gearbox has been rebuilt using NOS synchros, now those are rare today. I doubt the problem for Ian and Peter is in the gears themselves. More likely in the gear change mechanism. I would first remove the top remote cover, check all lock bolts are tight, then try a stronger shift rod detent spring on the 3/4 shift rod. This work can be done without removing the transmission from the car. It obviously only needs a bit more spring pressure on the shift rod to hold the gear in place under no load condition. BTW, worn TC synchros can be rebuilt with new brasses, I have done several sets. Ian must have a strange TC gearbox as most have 6 balls and springs in the synchromesh. Bob Grunau Peter, my Tc gearbox also jumps out of 3rd. on overrun - but i've got used to it and put my knee against it! During the rebuild I stripped the box to look for the reason and found that there were only two of the four synchro balls and springs on third. It must have been assembled like that as there is nowhere for them to go. Unfortunately replacing them made no difference so I live with it as a "feature" of the car. Ian Thomson. ----------------
>But I recall just recently someone stating that Redline is too good for the >TC trans. I guess it had something to do with the syncro rings not getting >a grip on their job. I have not experienced that problem, but my third
gear
>likes to go AWOL when not under a little torque. Some day I'd like to fix >that but fear I won't know what to look for.
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Re: TC Gearbox jumps out of gear

Posted: Mon Mar 04, 2002 7:34 am
by Peter Pleitner
Hi Bob and Ian, Thanks a lot for the info Bob. I suspected as much, and was hoping I wouldn't have to remove output shaft. I'll also look for gear engagement pattern. How about wear on the shift rod where the detent ball pops in? And please explain what you mean by "worn TC synchros can be rebuilt with new brasses". This could apply to any number of old tranys. I'd really like to learn more about the suspension properties of oil. I've been using Red Line in the TC's engine for a number of years. Does suspension enhance the ability of oil to carry particles to the filter? Bob, let me know when you are set to produce axle half shafts with a Morris spline. Last time we corresponded I didn't have time to search the garage attic to determine which hub I need. Just did that. So I also need a N/S rear hub, I found my spare O/S (driver's side) used hub in good condition. My goal is to keep the stock half shafts and hubs with the stock pumpkin assembly. Cheers, Peter

Re: TC Gearbox jumps out of gear

Posted: Tue Mar 05, 2002 9:04 am
by Robert Grunau
Hi Peter, Sure, wear on the shift rod could be a problem. Again, you can remove the shiftbrod for repair without removing the gearbox. Synchromesh brasses wear. On a NOS synchromesh hub when the brass is in contact with the next gear, the gap between steel gear teeth is 0.090". As the synchro wears, this gap is reduced. When the gap is as low as 0.040", you have essentially no synchro mesh action. The brass should be repaired/replaced. I have made up a jig to allow machining of new brass hubs for interference insertion into the TC sliding hubs. I still have some TC tapered axles and do not want to make a new batch till these are all gone. Just too much mponey sitting on the shelf. When I make new shafts, I will be able to make either TC or Morris inner splines. Regards, Bob Grunau Hi Bob and Ian, Thanks a lot for the info Bob. I suspected as much, and was hoping I wouldn't have to remove output shaft. I'll also look for gear engagement pattern. How about wear on the shift rod where the detent ball pops in? And please explain what you mean by "worn TC synchros can be rebuilt with new brasses". This could apply to any number of old tranys. I'd really like to learn more about the suspension properties of oil. I've been using Red Line in the TC's engine for a number of years. Does suspension enhance the ability of oil to carry particles to the filter? Bob, let me know when you are set to produce axle half shafts with a Morris spline. Last time we corresponded I didn't have time to search the garage attic to determine which hub I need. Just did that. So I also need a N/S rear hub, I found my spare O/S (driver's side) used hub in good condition. My goal is to keep the stock half shafts and hubs with the stock pumpkin assembly. Cheers, Peter --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.325 / Virus Database: 182 - Release Date: 2/19/02 --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.325 / Virus Database: 182 - Release Date: 2/19/02