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Triumph TR6 - Differential Noise

Need some advice folks. Just had the diff dropped & new bushing installed & mounts & pins reinforced and boxed. I still have the loud whirring noise and the TR6 guy says it's excessive backlash, maybe 200 thou. It's a lot anyway! Noise disappears turning right at any speed and is constant going straight or turning left. All my u-joints are good BTW. Hub bearings both appear good - smooth & no noise. The car is a '76. I understand the whirring noise may be caused by the pinion seating too far forward or back - too high or low on the crown and this can be remedied by realigning the pinion by adding or removing shims as necessary and renewing the spacer. Question: Will the '76 TR6 accept the solid spacer or must I use the collapsible type? That's just a start probably. Could I be looking at replacing the pinion head and tail bearings and the right and left diff carrier bearings? If so, with shims, spacer, oil seals & all I'm looking at a significant $$ amount for parts and still no guarantee that the sunwheel and planet gears are still good.It would seem too good to be true that with 125,000 mi on the clock I could buy a spacer and shims and correct the problem.I can buy a good used, low miles diff with zero backlash installed for $300 Canadian. Having spent a small fortune this winter I'm hoping to fix. As stated, it's a '76-6. Would appreciate advice on the solid spacer issue and any insight on the potential for looking at a major rebuild instead of a reasonably easy fix.

Thanks,
Bob
76-6
Bob Evans

Bob Forget about re-shiming the pinion as once a crown wheel and pinion have been set up and matched you cannot adjust the depth of mesh. What you can try is to address the backlash problem which will be relativly cheap and as you describe the noise goes away on right hand corners, your problem sounds to be a badly worn side carrier bearing, It is possible to do the job yourself but I would find someone with measuring tools and a hydraulic press
Clive P

Bob- Think of it this way. That baby is set up for the Nascar ovals. No left there!
Don
DON KELLY

Bob, go for the new diff, there are lots around.
Christopher Trace

Bob-Since you have the diff out, try removing the rear cover and check the backlash in the spider gears. I think this is the most common source of play in the diff and is cheap and easy to remedy with new thrust washers. Of course once the diff is apart it is easy to go down the path of replacing all bearings and seals. As far as pinion spacer types, they are not interchangable. The shank of the pinion differs according to the type of spacer used.
Berry Price
BTP Price

Bob the (sun and planet) or spider gears in the diff cannot contribute to the noise especially when driving straight ahead as they are not turning, The problem is in the crown wheel and pinion,
Clive P

Clive:

In your first answer you say it's likely a carrier bearing, which sounds very logical given that the noise disappears turning right(it's getting worse though). In your second response you say that the problem could be in the crown and pinion, which cannot be reset once positioned. Haynes states that the pinion placement on the crown can be adjusted with shims. Are you suggesting both carrier and crown and pinion as the problem? Berry says reshimming the spider gears could be a solution. Seems hard to diagnose on-line and I appreciate everybody's comments. I think I'll try the carrier bearing and order a bunch of shims for the pinion, and the spider gears. Should be able to get carrier and shims locally but the pinion spacer is another matter. It looks like the '76 has a collapsible spacer so that would have to come from Moss or TRF. A good used diff, however, with no backlash sounds better and better as I get more info.

Thanks,
Bob
Bob Evans

Bob Sorry If I have made you a little confused but I was never the best teacher, I said in my first mail that I thought your problem was a side carrier brg and I stand by this, The noise is not comming from the brg but it is causing the Crown wheel and pinion to go out of mesh and the noise is comming from there. The final drive and differential have 2 separate jobs and the car driven in a straight line could not be influenced by the diff. I agree that a secondhand unit may be the best bet,but you have to take the old one out whatever so before you part with your cash take a look inside, No special tools needed and you can get a better angle on the subject, Just remove the rear cover,remove the side flanges and lift the diff assy out, all will be evident Good luck and if you need help my email is cliveparkerauto@aol.com
Clive P

Bob-I only mentioned the thrust washers in the spider gears to address your problem of backlash. Don't order the spherical washers used on the planet gears until you measure the old ones. The other issues of noise depending on the direction is another matter. You are right, trying to diagnose a problem on line is pretty much a guessing game and only an autopsy of the diff will reveal the cause of the problem. The used diff for $300 could be a bargain or another source of problems. Rebuilding the diff can be done at home, if you enjoy learning experiences and have access to the tools needed (case spreader, dial indicator, micrometer, hydraulic press, bearing separator,etc. I have found the factory manual for the TR2-3 and Haynes manual to be the best source of info. Good luck.
Berry Price
BTP Price

Clive/Berry:

Thanks guys. Good explanation of the effects of the bad carrier bearing Clive. Makes sense. Berry, will heed advice on not buying parts til after the autopsy. I can get a carrier bearing here so could be a weekend project. The used diff is pretty much perfect as the guy took out his drive train from a beautifully restored TR6 and dropped in a 450 HP Chevy 350 and a 9-bolt Ford rear end. Many, many mods, roll cage, aluminum dash, dual shocks, lake pipes, etc. Awesome but very scary car (qtr mile in 11.9 sec). I'll e-mail Charile a couple of pics for the site. Thanks for the help. Paint next week.

Cheers,
Bob
Bob Evans

Rebuilt my diff. last winter and although it sounds and feels very good I have yet to install it in the car. A tip for spreading the case is to use a 3/4" pipe clamp; reverse the foot and grind the back of the clamps head flat....worked like a charm. I think I had the carrier in and out at least 4 times to get the correct lash/pattern. Just take your time and enjoy the fun! If you completly dismantle the diff. you could also put in a drain plug (1/8"NPT) and powdercoat the case. Mine looks great but I am a few years from test drive time... chasis is undergoing a major refit.

Rob
6,'76, white, hardtop, OD
Rob

Lake pipes on a TR6....that's a new one for the book.

Rick C
Rick Crawford

This thread was discussed between 16/05/2005 and 27/05/2005

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