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Gear box rebuild

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j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
I am rebuilding my gear box, new bearing, seals and syncro's, should I replace the syncro hub springs, I checked them and they look fine but could have lost some of there tension after 40+ years.



Joe
73 Triumph TR6

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trrdster Avatar
trrdster Wayne Tate
Spencer, NC, USA   USA
Joseph, If you look in the catalogs there is a spacer you can drop in the hole before putting in the spring. It will tighten it up a good bit. There is a poundage pull designed for that hub, but most of use don't have a tool to get it exactly right. Hate it, but close or snug is best I can get them.
Good luck.



Wayne
1970 TR6
2000 Jaguar XK8
1949 Triumph Roadster 2000
1978 Spitfire (rust victim)
1971 GT6 (tarp covered for 12 years, rusted inside out)
1980 Spitfire (getting all the good GT6 parts, all poly suspension and Spax shocks)

Bpt70gt Avatar
Bpt70gt Brian T
Westmoreland, NH, USA   USA
Joseph, as Wayne said but since you are this deep into the rebuild, why not check the syncro's. For first and second gear the load should be 21 to 26 lbs. for 3rd and 4th it should be 14 to 19 lbs. If you are doing this project, you have good skills so it should not be too hard to make the tool to check this. Got a friend with a lathe? I copied the tool shown in the book and made one. Works fine and is simple.
Thought I had a picture of mine but I can't find the picture.

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j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
Thanks for the tips guys, I will check the pull force after installing new springs. Also I will check what I have with old springs before replacing them. Always good to learn something new.



Joe
73 Triumph TR6

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
+1 on building the tool and doing the check. That detent force is what makes the synchro rings work, so it's actually kind of important. The tool can be as simple as an eye bolt and a couple of big flat washers. Your local sporting goods store should have a fish scale that will do to measure the force.

Don't forget to also measure the force on the shift rail detents, and consider replacing the shift rail seals.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

philstr6 phil Jaegeling
arroyo grande calif, USA   USA
Joe
heres what I use to ck the springs and ball to see how many lbs it takes to break them apart

fish scale,eye bolt with 2 washers and nut
Phil


Attachments:
IMG_0923.JPG    52.1 KB
IMG_0923.JPG

j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
Thanks Phil, I just picked up that same scale this afternoon, looks like it will work out fine, thanks for the info, working on the rebuild tomorrow before the football games, need to complete it, then pulling the engine.



Joe
73 Triumph TR6

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j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
Replaced the springs and ball combination on my 1st-2nd and 3rd-4th syncro hubs, checked pull force, 1st-2nd at 18-19lbs, 3rd-4th at 23-24lbs, good to go with those.



Joe
73 Triumph TR6

j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
I have a question on my reassembly, I have everything on the main shaft and I have play between the 1st and 2nd synchro and 1st gear, my spacer is in , there is a gab between back side of second gear and wear synchro butts up, is this normal, I have gone over the assembly many times and don't see any issues with it, I did not check that when I disassembled , but I am thinking there has to be movement for the synchro's to engage and disengage. Thanks for the info.



Joe
73 Triumph TR6

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Are you talking about the gap that is being checked in this photo? It's supposed to be there, and the width (with the synchro ring held against the gear) is an indicator of how badly the ring is worn.





Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild



Edited 1 time(s). Last edit at 2018-01-27 09:58 PM by TR3driver.

j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
Sync hub clearances are good , over + .030, attached is a photo of area I am concerned with, it has movement left to right, I tried attaching a video but for it wouldn't attach.



Joe
73 Triumph TR6


Attachments:
sync hub.jpg    48.6 KB
sync hub.jpg

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
The piece your fingers are on (shift ring) is held to the hub by the 3 balls & springs. The hub should have some room to move on the shaft. Around 1/16" IIRC, but exact value isn't important (and will grow as the synchro rings wear). But the ring should not move separately from the hub unless a fair amount of force is applied (numbers are in the book, ISTR around 20 lbf).

Once the top cover is in place, the shift forks will hold the shift ring (aka shift sleeves) away from the gear when that gear is not engaged (which allows the synchro ring to float in the gap, so it doesn't rub against the cone on the gear).



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
Randall , thanks for the info, I thought I had it together correct, I did install new springs and ball, also checked release force of sync rings. Hope to finish putting this together next weekend, then pulling the engine next.



Joe
73 Triumph TR6

j007 Avatar
j007 Joseph M
Madison, OH, USA   USA
I want to install new O rings on shafts of top section of gear box, I removed the outer ends on shaft but can't get center part off, it had a pin in it, does it have to be hit off or is it screwed in, not sure on this, I tried to hit it of and turn it but it doesn't move, looking for input on how this is removed. I attached pictures and you can see the hole where I removed the pin, looks like it should tap off. Thanks.



Joe
73 Triumph TR6


Attachments:
Top Cover gearbox1.jpg    51.9 KB
Top Cover gearbox1.jpg

Top cover gearbox2.jpg    58.9 KB
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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
IIRC its only supplied as an assembly with the shaft.
In any case, that's how I've always done it, remove the shafts to change those seals.

Also check that the O rings fit snugly in the cavity. On mine, the bore has been deeper than the thickness of the ring, so they leak unless you add a filler piece. MMC sells "backer rings" that work nicely, but only in a pack of 50.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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