Disturbing noise from transmission

[TRnorwegian]

I changed the clutch master cylinder last saturday, and the clutch is working again, allthough needing very macho legwork.

The noise however is still there, and while I had the car on stands I checked the rear wheels for slack, without detecting any abnormalties.
Seems the noise is coming from the transmission. It occurs when accellerating, most typically in 1. and 2. gear, and when going up hills, in short when the drive train must perform more than just cruising along.

Kind of metal scraping noise, disappearing as soon as I releases the accellerator or engage the clutch.

Does this sound familiar to anyone? Big problems?
If the transmission needs major work, I've considered going for a jap conversion, but logistics and transport would put med out of this season. So right now I'm looking for a quick fix

 

[Brosky]

Anders,

You say that you need a lot of pressure to engage or release the clutch? That along with your noise description, COULD POSSIBLY indicate a problem with the fork on the cross shaft and that would require removing the transmission.

 

[swift6]

TR6's are known for heavy clutches compared to more modern clutches. So the pressure requried may be right/wrong depending on what your comparing it too. Check it against another TR6.

 

[TRnorwegian]

The pressure needed is not extreme, and I guess many others struggle with the same syndrom. I've followed some treads on clutch pedal pressure, but so far haven't found any supplier/ fabricate more known for soft, pleasant clutch pressure than others. Seems to me some people complain, others are happy, but seemingly regardsless of which type they have installed.

Thrust washer defects have been suggested as source to the noise problem. Making sense?

 

[TRnorwegian]

A british friend pointed out the noise could derive from a tooth missing from pinion or crown wheel in the "back axle". Mostly since such a failure disappears as soon as power is removed.
The noise from such would probably be transmitted up the propellor shaft, appearing to be coming from the gearbox area.

 

[swift6]

Thrust washer defects have been suggested as source to the noise problem. Making sense?

Possible, easy to check without dropping the oil pan.

Get a prybar and lever the front crankshaft pulley back towards the engine. Then have someone get in and push the clutch pedal to the flor while you watch that front pulley. If you see the pulley move forward when the clutch is depressed then you have a thrust washer issue. If you don't see it move, you might still have a problem so don't think your out of the woods yet. If you don't see it move, then you might want to try and measure the movement. The acceptable endfloat is 0.006-0.008 inches (0.1524-0.2032 mm).

Really worn thrust washers can also be indicated by difficult shifting while the engine is running, but no problems shifting through the gears when the engine is off.

 

[TR3driver]

I've followed some treads on clutch pedal pressure, but so far haven't found any supplier/ fabricate more known for soft, pleasant clutch pressure than others.

You should check out Nelson's articles on the Buckeye Triumphs site then. He reported finding one combination that was so light he didn't like it.

Also lots of good material on problem spots to watch for, including sharp corners to round, clearances to check and so on.

Brent Kiser also wrote an excellent article on the subject of clutch parts (sorry, don't have the link handy, try Google) where he reported that many vendors are selling the WRONG pressure plate. He contacted AP (who now own the B&B name) to get the right part number.

 

[swift6]

Just read up on the similar thread on 6-PACK, and re-read this one. Missed that the noise isn't in all gears or while shifting. Tom has lots of good advice for you on the trans issues and the trans thrust washers. The engine thrust washer issue would be apparent in all gears, while shifting.

 

[TRnorwegian]

Just read up on the similar thread on 6-PACK, and re-read this one. Missed that the noise isn't in all gears or while shifting. Tom has lots of good advice for you on the trans issues and the trans thrust washers. The engine thrust washer issue would be apparent in all gears, while shifting.

No problems with the shifting. Perhaps the hypothese about a tooth missing from pinion or crown wheel in the back axle ist worth looking into?
I hope to drain the oil in the transmission in the coming week, and hope this will cast some light on whether or not the thrust washer there is a culprit.

 

[AltaKnight]

Anders
The thrust washers are on the rearmost main bearing inside the engine oil pan not the transmission.
It's the thrust washers that maintain the end float of the crankshaft particularly when depressing the clutch, when they get worn or fall out in extreme cases then the crankshaft will move visibly; check it like Shawn (swift6) recommends above.

 

[TR3driver]

Lots of thrust washers in various places on a TR; the crankshaft ones are only the most famous for causing problems. The thrust washers on the gearbox countershaft are also a known weak spot; and get loaded only in lower gears.

A broken tooth will be more of a clunk-clunk-clunk noise (as I recently learned the hard way).

One thing to look for might be the engine rocking over on it's mounts, and allowing something to contact that should not. Somewhat similar problem on the Stag turned out to be the alternator fan touching a radiator hose clamp. Of course it wouldn't be that exact problem on a TR6 but might be something similar.

 

[TexasKnucklehead]

Anders,
Some time ago my TR6 was making a terrible noise as well. Perhaps you could describe a little better how and when the noise is made.

I hope yours is different than mine, but my noise was only heard during "spirited" driving, and then pretty much only when shifting. I could not make it happen anytime I wanted, but heard it more than once, and getting more regular. I can't say about hills, because in and around Houston, there are no hills. Does your noise remain constant while climbing? Can you let off the accelerator and have it stop, then press back on it and have the noise come back? Anytime my noise happened, it startled me so much that I'd slack off the accelerator, and it would stop. Immediate romping on the accelerator would not reproduce the noise. I was so sure something was wrong, I pulled the transmission and had a good friend look it over. Peering inside all looked well and I was told to think about the diff. -but I should replace the syncros while I had it out. While taking it apart to replace them, I found the lockplate (item #65 from https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=32769&SortOrder=25) had broken, allowing the counter shaft to move back and forth. The resulting debris required significant overhaul, but I did it myself with parts from an old box for not too much cash -it could have been much worse. I shutter to think what could happen when a gear box locks up at 70mph. Don't let me make you paranoid, but I take metal noises coming from rotating masses very seriously.

Jer

 

[TRnorwegian]

A broken tooth will be more of a clunk-clunk-clunk noise (as I recently learned the hard way).

One thing to look for might be the engine rocking over on it's mounts, and allowing something to contact that should not. Somewhat similar problem on the Stag turned out to be the alternator fan touching a radiator hose clamp. Of course it wouldn't be that exact problem on a TR6 but might be something similar.

It's not clunk-clunk, more of a whining/scraping noise.

I'll certainly look into the engine-rocking, checking for contact that shouldn't be there. (I recently changed the petrol hose, and on the first test ride the alternator fan wore a hole into it.)
Could exhaust pipe movement do the same thing?

 

[TRnorwegian]

...could be heard during "spirited" driving, and then pretty much only when shifting. I could not make it happen anytime I wanted. Does your noise remain constant while climbing? Can you let off the accelerator and have it stop, then press back on it and have the noise come back?

Hi Jer,

It does not occur when shifting. Shifting is no problem, and also as long as I keep the clutch pedal to the bottom the noise is not present.
To make the noise appear only aquires pressing the throttle a tiny bit more when cruising, whatever gear I'm in( I thought earlier it only occuured when accellerating in 1. and 2.). When I let off the accellerator the noise stops.

Anders

 

[Gil]

You may want to look at your clutch housing cover plate also. If put on backwards the indentations of the plate face in and can rub the clutch disc. Sounds just as you described. Ask me how I know...

Gil