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Starting out in 1st gear knock or clunk

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N

Norton47

Jedi Warrior
Offline
I have notice a knock or clunk sometimes when starting from being stopped in first gear. Not always, but most of the time.
Anyway, checked the ujoints by raising car and having in neutral and twisiting things and can't find any slop. However, the right rear hub does have some play, not alot but it will move, the left does not.
Also the differential input shaft has slop or backlash. I would say a 1/16 of an inch or so, quite noticeable. It this to much? Is the hub bearing or the diff the culprite? or both? All the diff mounts have been replaced by PO with poly and look secure.
Where is a good place to get a rebuild diff it that's what's needed?

Thanks
 
Sounds like mine did when my first gear thrust washer disintegrated. Drain your tranny and check for pieces of metal.
 
Thanks
That is something that needs doing also, however the noise is distinctly in the rear.
 
If you have wire wheels it could be the splines or the knock offs maybe a little loose.

Patrick
 
Jack the car up and pull the rear tires, looking at the differential mount bridge. These commonly fail cracking from metal failure, usually a noticable clunk or knock when leaving a standing start. If you look carfully you may notice a crack where the bolt passes through the metal bridge. In the worst cases the bolt actualy snaps from it's mount if not repaired. It usually starts on the passenger side front.
If this turns out to be the problem the diff must be dropped & repair plated welded in . There is a PDF file available to make the repair plates.

The TR drivetrain is notorious for clunks so don't jump to conclsuions before checking.
 
Mark, Have you check out your dif mounting points. Bad karma there.
 
ok pulled the rear wheels and inspected the mounting of the differential. The aluminum casing appears uncracked and the foward steel yolk mounting is uncracked, the welded mounts fore and aft appear uncracked and rust free. The poly bushings are intact and the through bolts tight.
Are there any running or moving checks I should do to further identify possible problem area's?
 
Mark, you at home or do you have a lift next to you?
 
Working from home today. /ubbthreads/images/graemlins/devilgrin.gif
 
Sorry DNK, great minds think alike.

It's not the differential casting itself that cracks , but the metal plate sandwiched between the bushings. Very tough to see from the underside. If you know what your looking for you can spot it from the wheel side carfully following the the mount structure. Pull the passanger wheel & look in and locate the front diff mount. If memory serves me right, it's behind the coil spring but visible. A good light will help. Just follow the metal "V" shape that the bushings sandwich & look for or run your hand over feeling for a crack. It's hard to describe, when I did mine I kick myself for never taking any pics, it would help alot.
 
Sounds like it could well be a
cracked right front diff mount
stud box to me. First place I would look.

Sadly, you pretty much have to lower the
diff to verify the stud box condition. You might
as well install 4 new mount bushings if you go
to all that trouble to inspect the stud box.

Here is a decent photo of the stud box repair
almost at completion. A tip of the hat to the
photographer. His photo was of much help to me
rebuilding the Crypt Car rear end.javascript:
diffmount2.jpg
 
Just arrived home. Wendy happy, great cruise-
will post some photos and video clips later
this weekend.

d
 
I went to my local LBC shop to get a hand dialing in the carbs, I could not get them lean enough. Once we had that sorted, I had the mechanic move the car fore and aft while I listened. The clunk was sounding like was right under the seat and his opinion was a ujoint and listening from outside, I would have to agree. Only replacement will tell.
I did inspect the the mount that is sandwiched between the bushings and could not see any signs of cracking. I will definitely look again. I hate to drop the diff, but that might be the only solution. I need to rework a right rear hub also.
Thanks for the help.
 
[ QUOTE ]
Welcome back Dale. The crypt car saga continues.

[/ QUOTE ]



Man, I was starting to have withdrawal symptoms.
 
I actually have caught myself trolling over in the MG site looking for someone to help, er, bug. Hurry, Dale.
 
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