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Thread: TR6 Diff questions

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  1. #1
    Yoda Gliderman8's Avatar
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    TR6 Diff questions

    Having just completed the resto of my '73 TR6 I am starting to hear some "clunking" type noises from the rear of the car. Thinking it was the diff mounting points I crawled under to have a look and the mounts look fine.
    Next, I put the rear on stands and put it in first and reverse. In both cases, the rear passenger wheel had the drive while the drivers rear wheel barely turned at all and when it did it was quite "choppy"
    I was surprised that both wheels were not rotating when in first gear.
    Is this normal? Will both wheels rotate in a higher gear?
    If I need a new diff, is it better to rebuild the one I have or look to buy another one? Does anyone know what a fair price is to pay for a used diff?
    I know that I have posed a lot of questions, but I thank you all in advance for taking the time to answer.



    Elliot
    Central PA
    1973 TR6 Damson Plum / Biscuit interior, HVDA 5-speed, Good Parts Hubs
    1976 TR6 White/Biscuit interior SOLD
    Nostalgia isn't what it used to be.

  2. #2
    Tinster
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    Re: TR6 Diff questions

    Elliot-

    It was my experience I could not tell if the diif mount
    was OK or cracked without dropping the diff and sticking
    my face of close to the studs. Look at passenger side,
    front mount.

    Does it always make a noise or only on shifts?

    d

  3. #3
    Luke Skywalker trrdster2000's Avatar
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    Re: TR6 Diff questions

    Elliot, all is normal in the wheel turning department, unless you have a pos-track rear. Your clunk may very well be a universal joint as one wheel is hopping around with the axles hanging down. Check those first as rears are very high dollar items.

    Wayne
    '37 MG TA, '49 Triumph Roadster, '70 TR6, 2000 Jaguar XK8, '78 Spit6

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    Luke Skywalker
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    Re: TR6 Diff questions

    The TR6 stock differential is not a limited slip type so only one wheel will turn when you have it off the ground. The Quaiffe style differential is like a poitive traction type. That will turn the wheel with the least resistance. Mostly found on high performance cars.

    The clunking sound you hear is most likley from the axle, or broken mounts. Check to make sure the splines have grease and are not binding Also check the U joints.

    As for rebuilding, I would not buy a used one and expect it to be in good shape. Check with TRF or Mark at Macys Garage for prices. You can rebuild one yourself but you will spend some time and most likley take it apart many times before you get it right. You will also need the correct tools.

    Not sure of the type of restoration you did, but if the car sat for some time the splines may have dried up a bit.

    A rear shock may also be loose.
    Keith D
    1974 TR6 been the owner of this car for 37 years.
    1956 TR3 car is being restored.

  5. #5
    Obi Wan bgbassplyr's Avatar
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    Re: TR6 Diff questions

    The wheel with the least resistance in the u joints, bearings and brakes will rotate while the other remains stationary. Thats how a differential works. When a turn is made, the wheels rotate at different rates and the drive is focused on the slower moving wheel, ie, the inside wheel. When you make a hard turn and apply power, the inside wheel will spin because it is unloaded, and you loose drive because all the power is just spinning the wheel. That why locking differentials were invented. When one wheel exceeds the rate of spin to the other, an internal clutch mechanisim ties both axles together, bypassing the function of the differential.

    You will notice that with the rear wheels off the ground, gearbox in neutral, when one wheel is rotated, the other wheel will turn in the opposite direction due to the way the spider gears work. Wish I could give a better explaination. Also wish I had a million $.

    The clunk could be any of the following:

    1. bad axel u joint, either inner or outer.
    2. bad drive shaft u joint.
    3. loose or broken diff mount, rubber or frame.
    4. bad pinion bearing allowing slop between the pinion and ring gear.
    5. worn ring and pinion due to use/age.

    Use a lever/pry bar to really load the diff against the mounts to check for breaks/ damage. Shaking by hand will not reveal problems here.

    Check all the u joints in the usual way.

    If you set the e-brake, gearbox in nuetral, and rotate the driveshaft back and forth, you will be able to tell how much free play in the pinion/ring gear there is. I don't remember how much you should be able rotate the driveshaft bump to bump, but it seems reasonable that more than an eighth of a turn would be too much, and indicate trouble within. Rebuilding is best done by a professional. Buying used is a crap shoot, IMHO.

    Hope this helps, and if I have any of it wrong, others are invited to correct me. No offense taken.

    Oh, and be sure it is not a tail pipe or muffler hitting something.

    Good luck, Jim
    LBC's previously owned:
    2 '59 TR3As, 1 Driven, 1 raced in '64
    '61 & '68 Corvairs, both 4 carb (non LBC)
    Sunbeam Alpine (former wife loved it)
    Volvo 122S (non LBC)
    '46 MGTC 0442
    '62 Sprite (racer)
    Currently owned:
    '62 TR4 (CT5586 L) bought 1990, stored until 2008, now undergoing refurbish for a driver.

    Jim Browne

    A legend in my spare time.
    I started with nothing and still have most of it.

  6. #6
    Yoda poolboy's Avatar
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    Re: TR6 Diff questions

    Yeah, I doubt that you will hear the noise from a cracked differential mount with the wheels off the ground. From my experience there has to be some resistance to the torque from the differential for the crack to make the click or clunk.
    Under what conditions did you hear the noise ?
    Ken @
    kencorsaw "at" aol.com
    DRIVE 'EM IF YOU GOT 'EM

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    Yoda Gliderman8's Avatar
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    Re: TR6 Diff questions

    I did install new universals when I did the resto but who knows... I guess they could be bad.
    As for the rear shock, I never even gave that a thought...
    Wow, I like this forum... the more heads the better.
    Thanks guys!
    Elliot
    Central PA
    1973 TR6 Damson Plum / Biscuit interior, HVDA 5-speed, Good Parts Hubs
    1976 TR6 White/Biscuit interior SOLD
    Nostalgia isn't what it used to be.

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    Yoda poolboy's Avatar
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    Re: TR6 Diff questions

    Quote Originally Posted by poolboy
    .................................................. .................................................. .................................................. .................................................. ......................................
    Under what conditions did you hear the noise ?
    Ken @
    kencorsaw "at" aol.com
    DRIVE 'EM IF YOU GOT 'EM

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    Great Pumpkin - R.I.P TR3driver's Avatar
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    Re: TR6 Diff questions

    Just wanted to echo the comments above; you can't tell if the mounts are bad by looking, because the diff is in the way. Grab it, do your best to shake it loose from the car, you probably still can't tell. Only way to be sure is to drop the diff and do a visual.

    Here's what I found in the 'rebuilt' diff I bought for my Stag:
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

  10. #10
    Yoda Gliderman8's Avatar
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    Re: TR6 Diff questions

    Specifically, I hear a slight clunk unpon putting into first, so that is what made me think it was the diff mounts.
    BUT, I also hear some noise that when the car in in motion with car in gear and foot both on/off of accelerator.

    P.S. Dale et al-
    You are right... I plan on dropping the diff to see what's going on with the mounts.
    Elliot
    Central PA
    1973 TR6 Damson Plum / Biscuit interior, HVDA 5-speed, Good Parts Hubs
    1976 TR6 White/Biscuit interior SOLD
    Nostalgia isn't what it used to be.

  11. #11
    Yoda poolboy's Avatar
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    Re: TR6 Diff questions

    If it's not the actual metal brackets that have the "pin" that the rubber mounts fit on, it might be that the inner metal sleeve in the original type rear mounts have come loose from the rubber that surrounds it. It's kind of vulcanzed to the rubber and when it breaks free, it clinks around upon the differential mount pin.
    Easy to check W/O dropping the differential. Just remove the 2 nuts that hold the plate to the differential and the center nut that holds the mount to the "pin". If you do one at a time the differential won't move.
    Ken @
    kencorsaw "at" aol.com
    DRIVE 'EM IF YOU GOT 'EM

  12. #12
    Tinster
    Guest

    Re: TR6 Diff questions

    Elliott: I live in kind of a remote place in terms of LBCs.

    My 69 TR6 came with clunk when it was purchased. I knew
    very little about auto mechanics but everything I read
    pointed to a broken diff mount, passenger side front.

    I rented some lift time and rented two professional mechanics
    to drop the diff so I could inspect the pins/mounts. Broken
    pin/mount had already been repaired. I had the diff put back
    with a new TRF mounting kit.

    In retrospec Big mistake putting it right back in.
    Out, I could have checked:

    1. bad axel u joint, either inner or outer.
    2. bad drive shaft u joint.
    3. dry splines in axles
    4. pulled off the diff rear plate and listened for bad pinion
    bearing allowing slop between the pinion and ring gear.
    5. worn ring and pinion due to use/age.

    But I didn't know at the time to do this. So the diff went
    back in and I replaced all those components and still have my
    clunk to this day. It's inside the diff.

    I bought a spare diff and it has no clunck. Live and learn.
    And yeah, the first thing I discovered was neither rear shock was attached to the car. But they don't clunk.

    best of luck with your clunk/

    dale(Tinster)

  13. #13
    Jedi Warrior RJS's Avatar
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    Re: TR6 Diff questions

    Hey Guys,

    After 8 years I finally addressed the clunking in the rear of my TR4A. It would clunk in 1st gear - especially after backing out of the garage. A visual led me to believe it was not the diff mounts. By getting under the car on jackstands and alternately holding/rotating the driveshaft and axel shafts, I was able to isolate the play as being inside the diff. I would say the rotational play was ~1/2".

    So, I dropped the diff which was amazingly easy. Took all of 45 minutes by myself using a floor jack to lower it. Four bolts on the driveshaft, four on each axel shaft, four diff mount bolts and out it came. Now I could confirm it was not the diff mount. I then had the diff rebuilt by Quantum Mechanics. It leaked oil like mad but, fortunately the crown & pinion were in excellent shape b/c I always kept it topped up. So, all the play was b/t the spider gears as all the old brass and fiber washers/shims had long since disintegrated. So, I got three new bearing, three new oils seals and the spider gears re-shimed for a very reasonable cost. Plus, he tapped an oil drain hole in the bottom so I can now change my diff fluid every few years. One thing I will say, this is VERY specialized work which requires very special (hard to find) tools and the hand of an experience professional to set the tolerances just right.

    While the diff was out I used it as an opportunity to pull the sliding axel shafts apart to inspect and relube with moly grease. I also stripped and repainted the diff mounts. Lastly I improved on the original rubber bushings in two ways: 1) I opted NOT to go with polyurethane bushings but used original rubber 2) the hole in the bushing was not snug around the diff mount pin so I used some pvc tubing from Home Depot and cut a length to "sleeve" it (slid it right up over the pin to remove the slack) 3) I welded a slight side wall to the rear two washers creating a little "cup" for the bushing to sit in (TR6 set-up is slightly different I think so this may not apply).

    Got the diff back, had it installed in a little over an hour and very, very happy with the results.

    Bob
    1966 TR4A IRS

  14. #14
    Jedi Knight BobbyD's Avatar
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    Re: TR6 Diff questions

    Unless your diff mount is seriously ugly flat out broken in two you'll have to drop the diff to try and see if it's cracked. After removing mine and hitting the mount with a wire wheel and sandpaper I was finally able to see where the cracks where......as you can see, it only takes a hairline crack to cause the dreaded clunk! Then I got mine boxed in and the clunk went away.

    Bob Danielson
    TR4/250/6 Fender Blankets
    http://tr6.danielsonfamily.org/FenderBlanket.htm
    1975 TR6 CF38503U
    Running w/ Throttle Body Injection,
    Toyota 5 Speed & Nissan LSD
    http://tr6.danielsonfamily.org

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    Great Pumpkin - R.I.P TR3driver's Avatar
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    Re: TR6 Diff questions

    Quote Originally Posted by RJS
    One thing I will say, this is VERY specialized work which requires very special (hard to find) tools
    It's actually not that bad, IMO. The special factory tools definitely make the job easier and quicker; but it can be done with just relatively common tools (hydraulic press, bearing separator, dial indicator etc.) and persistence.

    The case spreader is not essential, the carrier can be pried out and tapped back in without spreading the case.



    Instead of using the pinion depth gauge, you can assemble the unit and check the tooth contact pattern. When it looks like this, you're good to go.



    The only tools I had to fabricate were bars for various holding functions



    and a little mount for the dial indicator (to measure carrier end float)

    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

  16. #16
    Great Pumpkin DNK's Avatar
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    Re: TR6 Diff questions

    [QUOTE= TR3driver]
    Quote Originally Posted by RJS
    ...The special factory tools definitely make the job easier and quicker; but it can be done with just relatively common tools (...
    Randle- All I got is an old craftsman 4" vice ,a rust pair of channel locks and a broken flat blade screw driver.
    Any chances I can do this?
    Don
    "Stick a Wedge in it!"
    Mount Pleasant,SC

  17. #17
    Great Pumpkin - R.I.P TR3driver's Avatar
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    Re: TR6 Diff questions

    Quote Originally Posted by DNK
    Randle- All I got is an old craftsman 4" vice ,a rust pair of channel locks and a broken flat blade screw driver.
    Any chances I can do this?
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

  18. #18
    Yoda
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    Re: TR6 Diff questions

    Don - you bought a screw driver finally?

  19. #19
    Yoda poolboy's Avatar
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    Re: TR6 Diff questions

    I bet Don found it on the road.
    Ken @
    kencorsaw "at" aol.com
    DRIVE 'EM IF YOU GOT 'EM

  20. #20
    Obi Wan bgbassplyr's Avatar
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    Re: TR6 Diff questions

    [QUOTE= DNK]
    Quote Originally Posted by TR3driver
    Quote Originally Posted by RJS
    ...The special factory tools definitely make the job easier and quicker; but it can be done with just relatively common tools (...
    Randle- All I got is an old craftsman 4" vice ,a rust pair of channel locks and a broken flat blade screw driver.
    Any chances I can do this?
    2 chances


    slim and none.
    LBC's previously owned:
    2 '59 TR3As, 1 Driven, 1 raced in '64
    '61 & '68 Corvairs, both 4 carb (non LBC)
    Sunbeam Alpine (former wife loved it)
    Volvo 122S (non LBC)
    '46 MGTC 0442
    '62 Sprite (racer)
    Currently owned:
    '62 TR4 (CT5586 L) bought 1990, stored until 2008, now undergoing refurbish for a driver.

    Jim Browne

    A legend in my spare time.
    I started with nothing and still have most of it.

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