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Axle Clunk!


Guest hodgie

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Guest hodgie

So, the TR8 is on the road and approx 6 mths ago i had a new 3:08 diff fitted.

When i pull away and change gear hard, there is a bit of a clunk from the axle.

 

Having had the car up on the ramp, when the prop shaft is tuned it takes a little rotation befor eit picks up the halfshafts and turns the wheels. I presume that it is this that is causing the slack and hence the noise. It's not horrific, but gives a bit of a 'loose' feeling.

 

Is this normal? Or could the diff have been shimmed up incorrectly?

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Assuming that the universals are ok, you may have a problem with the diff, however i had a similar noise some time back that turned out to be the exhaust hitting one of the suspension arms under severe acceleration, if this is the case you will see a shiny patch or a small dent where it is hitting.

 

Check that rear end before you give the company who fitted the diff gears a hard time, i just crawled my race 8 and it has a little bit of movement but no clunks.

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High all, new poster here.

We had this problem with a high power [280 BHP] TR8.

We finally traced it to the washers used on the trailing arms, &/or radius rods.

They are supposed to have thick washers, [to spread the load, I suppose].

When we sourced some thick washers, of the right, rather large diameter,

the cluncking disapeared.

While testing this theory, we fitted the genuine washers, off a standard 7.

The clunk went, but the 7, with the thin washers off the 8 fitted, started to clunk,

although only lightly. The thin washers were slightly distorted from flat, when

removed from the 8.

Hasbeen

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  • 2 weeks later...

Are we talking about the washers that fit either side of the trailing arm mounting point?

The knock I am getting is when i come on and off the throttle.

 

If you kangarroed it would feel like the back of the car was falling off!!

 

It's either some slack in the drivetrain or the rear end a little loose, but having checked everything for tightness, i can't find any cause for it other than a little take up slack in the diff/half shafts.

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Yes, thats the ones. We chased that noise for months.

By the finish we had;

1/ Poly bushes, with less than 5000 miles on them.

2/ A new prop shaft, with UJs, replacing the CVs.

3/ A brand new limited slip high performance diff.

4/ New axles, & discs. This car has Nissan discs on the rear.

5/ New mounting point bolts, tightened with a breaker bar.

We still had the clunk.

It was then that I noticed thw word "THICK" in the description of these washers,

in my manual.

We had checked the thing on a ramp, changing from forward to reverse, with the

car held on the breakes, without finding anything.

We then made very large chocks for front wheels, to clamp to the ramp.

Eureka, with no breaks, there was a noise from the trailing arm, & radius rod

mounting piont, as we changed from forward to reverse.

I pinched the washers off my 2L 7, & fitted them to the 8. You beauty, no noise.

Went for a drive. NO NOISE.

12 months, & many miles later, no noise.

There is not even that much difference in the thickness of the washers, but it makes

all the difference on the car.

The original lighter washers had distorted to slightly convex, but we had been

screwing the mounting bolts very tight.

Yes, I agree, its bl@@dy ridicules, but it worked on our car.

Hasbeen

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Its also worth checking the bodywork around the lower mountings for cracks, this is a common place for rust amd metal fatigue, one of my previous DHC's used to knock from the rear on hard acceleration & deceleration, (I had already replaced the bushes after it started to steer from the back end!) so had another look and found the bodywork around both lower mountings had stress cracks so got them welded and problem solved no knocks or clunks & a much better drive!

Edited by CraigAddison
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  • 5 months later...
High all, new poster here.

We had this problem with a high power [280 BHP] TR8.

We finally traced it to the washers used on the trailing arms, &/or radius rods.

They are supposed to have thick washers, [to spread the load, I suppose].

When we sourced some thick washers, of the right, rather large diameter,

the cluncking disapeared.

While testing this theory, we fitted the genuine washers, off a standard 7.

The clunk went, but the 7, with the thin washers off the 8 fitted, started to clunk,

although only lightly. The thin washers were slightly distorted from flat, when

removed from the 8.

Hasbeen

 

Had similar promlem with TR8. Found that thin(er) washer had been fitted and they had been distroted into a concave shape when the trailing arm bolts tightened. Replaced with thick wasers as per OEM and problem solved - no clunks! Thanks for the tip

 

Robert

KiwiTR5

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The parts lists (Moss & Rimmers) actually show a washer under the nylock nuts only (4 places - fore & aft of each trailing arm)

The item was originally P/n WM803 which now superseeds to WC600071 which is quoted as 3/8"ID 1"OD washer and also used on TR4A-TR6 rear suspension. I have no specification to hand re the thicknes of WM803 but it is very likely that it was a substancial piece probably at least 2mm thick. Anyhow, installing washers of this dimension on the TR8 under all 4 nuts and also the heads of the bolts (8 total) seems to have solved the problem

 

Robert

Kiwi Tr5

Edited by KiwiTR5
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Thanks for the feedback KiwiTR5.

When you post such an unlikely cure for a problem, its nice to have your result confirmed. You know half the readers will think you are mad, or that the cure was actually something else, that you fixed without knowing.

 

I am glad that you have confirmed my diagnosis, & that the months of frustration we had finding it, have helped another wedger.

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