TR2/3/3A Transmission / drive shaft knock ??

[Big D]

Recently my 1960 TR3A has been making a strange noise from the drive system. In 1st OR reverse there is a sound almost like something is striking against one of the drive shaft bolts. It's not a horrible sound, just a constant 'tick' that changes in step with the engine RPM. The curious thing is that this does NOT happen when in the higher gears.

If something were interfering with the drive-shaft rotation the sound would happen in ALL gears, no ??

Any ideas out there ??

Thanks in advance,
Don

 

[Merlin63Tr4]

Sounds like a broken gear tooth.
If it was something striking the drive shaft the noise would happen in all gears.

M.

 

[Big D]

Sounds like a broken gear tooth.
If it was something striking the drive shaft the noise would happen in all gears.

M.

Merlin - If it were a broken gear tooth, why would it just happen in 1st gear AND reverse ???

 

[CJD]

1st and reverse use the same gear...

 

[Big D]

Ahhhhhh !! uh oh. I need to pull the tranny then ??

 

[CJD]

It's like spinning the roulette wheel every time you run it. Sonner or later that tooth will get picked up and get caught between other gears...shelling the entire tranny. Best to take care of it while it's just one gear and maybe a couple bearings.

Tried to post a pic, but I'm at the kids high school, and they seem to have photbucket locked out here. There are 2 possible gears that it could be...

If it is relatively high frequency, like several clicks per revolution, then it's the "cluster gear...

https://www.ebay.com/itm/Triumph-TR...m1a08173046:m:mdgOlfsFvoEtwYHxDqvD2hg&vxp=mtr

If it is lower frequency, then it's the 1st/reverse slider gear...

https://www.ebay.com/itm/TRIUMPH-TR...ash=item5b1bb2a220:g:wJ0AAOSw~gRV4JHD&vxp=mtr

 

[Merlin63Tr4]

Don,
John beat me in posting a reply.
Yes, looks like it is time to pull the trans.
At least, all the good driving weather is pretty much over out where you are.

M.

 

[Big D]

Don,
John beat me in posting a reply.
Yes, looks like it is time to pull the trans.
At least, all the good driving weather is pretty much over out where you are.

M.

John / Merlin,

Thank you both for your wisdom and advice. My plan is to remove the tunnel cover and disconnect the drive shaft. If the noise (tick) is still there, it's the tranny for sure. By the way John, the tick is quite slow so it may indeed be the slider gear.

I've done some research and it looks like replacing this gear would be a MAJOR project. If it is the tranny, I'm going on the hunt for a rebuilt gearbox.

Thanks again guys,
Don

 

[bnw]

I had that noise once. Back in 1970 I was waiting for my wife to return from shopping. I had lots of time so I pulled the shifter cover from the gear box to take a look. Couldn't see anything so I started it up. That stinky gear oil started flying everywhere so I grabbed a T shirt from the rear bench to cover the opening. The shirt got sucked in instantly and killed the engine. I had to tow the car to a Ford dealership where there was a tech who moonlighted Triumph gear box repairs. He replaced the gearbox with a TR4 unit for about $125 I recall. BTW, it was a tooth on the cluster gear. To this day, no matter what standard trans I'm driving, I always drop back to 2nd before I engage 1st or reverse.

 

[Merlin63Tr4]

Here's my "war" story,
A couple of years ago on a cold rainy day, I lost the needle bearings in the cluster gear/layshaft some 20 miles from home .
It is really amazing how much noise that failure causes. Almost like metal shot being fed thru a meat grinder.
Somehow I made it home. The amount of shrapnel that came out with the gear oil when I drained the transmission was mind-blowing…..
Of course the shrapnel circulated thru the OD and that had to be replaced too....

M.

 

[bobhustead]

Unloading the trans by pulling the driveshaft might reduce the click to inaudible, giving you false hope.
Bob

 

[sp53]

These transmissions are not difficult to rebuild and there is an excellent chapter in the Haynes manual on how to do without any specialty tools. If the trans is OD that is more complicated, and I have not done one. John posted some excellent pictures on that. In addition there are People who specialize in rebuilding these and their prices seem reasonable. I think you should give it a go with the help on the form, and you will be pleasantly surprised with the results. Many places only want a core and I bet they would take a basket case as a core. Nothing to lose and knowledge to gain.

 

[sail]

Bummer. I rebuilt my gearbox with no experience, so another vote for it can be done if your up for it. It is a big job as you might expect, but rewarding.

Greasy Hands was main resource: https://vintagetriumphregister.org/maintenance/

Parts came from Quantum Mechanics who is in your area. He also rebuilds units: https://www.quantumechanics.com

 

[TR-3rg]

Hi,

I rebuilt my 3a gearbox with parts from TRF. I drove it for a week and broke a tooth off it by jamming it in 1st gear at a stop light. I followed the instructions in VTR without issue. About a year later I picked up a TR-4 box and rebuilt it. This time I bought the kit from Quantum Mechanics and followed the instruction in Buckeye Triumph. In both cases, I replaced the springs and ball detents in the 1-2, 3-4 shifter hub.

Personally, I would find a TR-4 or later gearbox and use that. A nice TR-4 gearbox is a lot of fun to drive. The next gearshift is a click away. They are that smooth!

Roy

 

[mallard]

I'm not the best at transmissions, but can't you remove the trans cover, drain the oil, and inspect all the gears before you remove the whole thing?

 

[CJD]

I'm not the best at transmissions, but can't you remove the trans cover, drain the oil, and inspect all the gears before you remove the whole thing?

1st /reverse, yes. The cluster gear is buried, though. Maybe if you are persistent with a mirror or one of those fancy snake cameras they have at autozone these days.

 

[TexasKnucklehead]

I broke a tooth off 1st twice. Both times required a complete disassemble before I could see the broken tooth -as John said, it's buried. The second time I broke off a tooth, I didn't want to deal with it but wanted to drive the car. I drained the oil but the broken tooth didn't fall out. So I dragged a strong magnet across the underside of the case until I managed to drag the broken tooth to the hole, and fished it out. Then I put the used oil back in, and drove the car (avoiding 1st gear) for another few months until I had time to rebuild it properly. The real danger is having that broken tooth find it's way into a spot where it can very quickly make things much worse. Aside from constantly forgetting to start in 2nd, it worked fine. It only clicked when I had it in 1st -reverse may have made a click too, but I generally try to drive forward.