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TR6 TR6 rear end knocking

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Olafthor

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When I start from a dead stop and let the clutch out in 1st, the rear end wants to jump and knock around abit. As the read end gets under constant load in 3rd and 4th gears, the shifting is smooth.

Any advice on where to start looking? Thanks.
 
Safely put the car on jackstands and have a good look around, may be as simple as u-joints could be worse.
 
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If you don't see anything, likely it's time to drop the diff so you can see the mounts above it. It's a known weak spot, and hard to see with the diff in place. Most vendors sell a reinforcing kit to be welded in place.
 
When you get the car up in the air, if you are able to clean in the area of the differential mounts, you might be able to see if there are any cracks. Certainly dropping the differential is the better way to check it out but this is a monumental task in that everything comes out. A really good flashlight will tell you a lot about the general condition of the mounts. The options for repairing the mount are to do it from the bottom (welders hate this) or from the top, by cutting doors into the rear shelf and welding it back up. Hope it is just a u-joint.
 
We had this same problem crop up at one of our Triumph club Saturday tech sessions. With the car on the lift, we were able to determine that the diff mounts (the rubber pieces) themselves were the culprits, and not the dreaded mounting points that always seem to crack. We put in new mounts, and the car has been fine since.

It will take some careful observation and probing around to find the exact cause, but anytime the diff starts clanking around, it's usually the mounts, or cracks in the mounting points to the frame.
 
The same thing was going on with my Car.
The universal Joints were shot and there was fragmentation noise inside the differental..

I ended up changing the Differential, and both rear axel assemblies, along with new differential mounts. At the same time I repair welded the differntail mounts. Thanx to john at Quantum I was able to get the rebuilt rear end and axels at a fair price. I'm gald I did the entire job all at one time because i really did not want to fix it in stages, your sitcuation may be less involved (I hope!)

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This is what I found when I had that noise. In case you you can't make it out it is one of the differential mounting brackets. I had it welded and even had a reinforcing plate welded on top of that and the other brackets...took it for test drive and still had a knocking noise although not as bad....this time it was the rear shock that had worked loose!!
 
Thanks for all of the replies. I'll have a chance to take a good look underneath this holiday weekend. I'll report with I find. Thanks again for all of your advice.
 
Well, after getting a good look around, I was able to feel a crack in the passenger side differential mount (not on the differential but on the mounting bracket).

What would be the best sequence to remove parts to get this to repair?

Also, any further advice on what I should change out while I'm down there? Many thanks.
 
That's the one that always breaks. You gotta drop the diff, which basically means the entire rear has gotta come out.

Or, have someone cut doors in the top of the rear shelf and go that way. Or course, the whole interior (carpet, panels, top, etc.) has to come out.

The top approach is the simplest, unless it is time to rebuild all your U-joints and bushings. Then it makes sense to go though the bottom. You will have to find a welder who is good at standing on his head and stacking BB's if you go from the bottom.

There is actually another way. Take the body off.......
 
Do you have a Bentley manual? Just follow the instructions for and it is pretty complete. Make sure that you have (purchase or rent or borrow) a transmission lift. That diff is scary heavy.
 
Olaf,

This "How to" will show you how to remove and replace
most of the rear end. It will get you into the diffy.
You will need to disconnect the drive shaft and your
exhaust system pipes may vary and need to be removed
as well. Mine did not.

https://www.scribd.com/doc/92509/TrailingArmBushingsFinal

This "How To" plus Bentley will show you how to refurbish
the rear suspension once you have repaired the diffy mount.
The Roadster Factory and Moss Motors both sell the diffy
mount repair box.

I am non-mechanic Tr6 owner and I was able to take apart
the rear end. Slow but it can be done.

Best of luck. There is a whole bunch of willing help
right here on the forum if you get stuck. Post a photo
of your problem- you'll get some quick answers.

tinster
 
Hey cuz, you MAY be a non-mechanic owner, but you're the kinda guy that Standard wishes had purchased each of their cars. You're no dummy! You think through the disassembly process, cataloguing items removed, rather than just tossing them in a jumble, clean and reinstall/repair/remanufacture with intelligence.

You have climbed one of the highest mountains by "resurrecting" Amos, from Don Pedro's "Crypty". So I, for one, am giving you a great big pat on the back, and telling you that you need to reward yourself by at the very least celebrating with a good shot of Johnny Walker Blue.

Slainte
 
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