Drive Line Clunk from rear

[DB6]

Just drove the car hard for 80 miles and noticed a clunk coming from rear whilst driving as accelerator is pushed then backed off(patic at lower speeds around town, I also noticed I can get the same clunk by putting car in gear in garage and rocking back and forth, this is on a 1984 Caterham Xflow with live (Ital, Triumph) rear end with a LSD.

Any ideas where I should start to look ?

Anyone notice their car does the same in gear whilst rocking, I know there is always going to be some play and noise but this is loud.

Thanks

David

[Ian7]

Although you didn't specify what type of LSD you have, its still the first place I'd look, especially if the diff is 28 years old !!

Possible that the internal components are worn or worse, broken loose, inside the housing.

Cheers

[slomove]

I have had such a "clunk" all the time. Kind of got used to it.

 

I though it was just the play of all the gears in the tranny and the diff.

Is it in all gears the same?

 

Let me know if I should finally worry about it....

 

Gert

[slngsht]

start with easy stuff first... check all your suspension links for any play

[MHKflyer52]

start with easy stuff first... check all your suspension links for any play

 

I agree but also look at the diferental mounts if it is IRS and the U-joints for play.

[DB6]

Thanks for the input guys,

The whole engine and driveline (incl LSD, I think its Quaife) was replaced /reconed in 2002 by a good VA race shop and has less than 2 K on it.

the clunk is in all gears but more noticeable at low speeds, guess cuz I can hear more.

To be honest there has always been a bit of a clunk, but today I really noticed it as I was in stop start traffic partic at around 20mph then backing off the accel and speeding up again.

So if you guys put your car in gear and rock it do you get that "metallic thunk" ?

Regards

DB

 

PS, this is the old live axle style no IRS sadly.

[yellowss7]

I tend to agree with Martin. Check the driveshaft U joints. tom

[DB6]

I tend to agree with Martin. Check the driveshaft U joints. tom

 

Thanks all, I will.

[slomove]

I did a quick test....The play in the drive-train with gear engaged allows my car to roll back and forth about 1.25" (with a Toyota live-axle/diff and Quaife LSDand 15" wheels). Watching the propshaft motion while rocking the car, I would estimate that maybe 2/3 of the total play comes from the diff and 1/3 from the gearbox.

 

Gert

[DB6]

I did a quick test....The play in the drive-train with gear engaged allows my car to roll back and forth about 1.25" (with a Toyota live-axle/diff and Quaife LSDand 15" wheels). Watching the propshaft motion while rocking the car, I would estimate that maybe 2/3 of the total play comes from the diff and 1/3 from the gearbox.

 

Gert

Thanks for that,

do you hear a clunk??

[slngsht]

Thanks for that,

do you hear a clunk??

 

From post #3, slomove said: "I have had such a "clunk" all the time. Kind of got used to it."

[bsimon]

I've built many 9" Ford diffs. over the years. The Ital is a very similar drop out carrier axle assembly. If you don't find external problems like suspension bushes, U-joints, ect., I would suspect that the bearing adjustment nut on the port side of the carrier has backed off for some reason or one of the carrier bearings has shot craps. Someone may have forgotten to bolt up the adjustment keepers or used an improper preload when they rebuilt it last.

 

Hopefully you'll find an external problem that others have pointed to. If not I'm afraid the carrier will have to be pulled out of the front of the axle and rebuilt.

 

Good luck.

 

 

[soareyes]

Like Gert, I have a Birkin live axle and have always had the clunk.

 

 

 

[TheDingo8MyBaby]

Check your A-frame bushings. They tend to wear out-especially if the diff is leaking.

[DB6]

Check your A-frame bushings. They tend to wear out-especially if the diff is leaking.

 

Yeah I will check those out too.

Odd thing is it really only gets noticeable after a hard drive when everything is hot, I was wondering is the oil thinning in the dif with heat could do that and maybe putting in a heavier oil/ additive may help.

By the way what do you guys recco for dif/axle oil in a 7?

Also, what is good in the Ford Escort GT 4 speed box with CR, funnily enough that gets balky when hot too.

A friend swears by MGC (Multi Gear Concentrate) an additive to quieten metal to metal noise and stop leaks, it can be used on noisy power steering pumps too .

By the way are these Ital axles renowned for drips and leaks?

thanks

David

[southwind25]

Beware the "clAnk....clunk is not bad...clank is

[xflow7]

Check your A-frame bushings. They tend to wear out-especially if the diff is leaking.

 

I second this. And in my experience, they can start to make noise before they are obviously (while installed anyway) worn. In 11k miles, I've replaced mine several times. The good news is the parts cost is about 10 bucks and it's a 20-30 minute job.

[DB6]

 

I second this. And in my experience, they can start to make noise before they are obviously (while installed anyway) worn. In 11k miles, I've replaced mine several times. The good news is the parts cost is about 10 bucks and it's a 20-30 minute job.

 

Where are they ?

[lowflyer]

I had a similar "clunk" in my Stalker.

 

After much looking, testing, etc. I discovered it was caused by a can of tire sealant rolling rearward and hitting the bulkhead under acceleration. The can had a piece of towel wrapped around it with a rubber band on it, to keep it from rattling against the metal floor. The rubber band had broken and the can had "unwrapped" itself causing the metal to metal contact. I was even able to reproduce the noise in the garage with the engine off.

 

I'm not suggesting that this is your problem, but sometimes the easiest and most obvious things are overlooked because we are looking for a real mechanical problem.

 

On another occasion, I found that the locking nuts on the rear trailing arms had worked themselves loose in two spots. No noise, just found them while doing some normal maintenance.

 

It's all part of the "fun" associated with our type of car.

 

:party:

[TheDingo8MyBaby]

 

Where are they ?

 

They're at the point of that A shape piece underneath your diff. I think this is most likely your cause.

 

They're really easy to change. Jack up car, unbolt and pull out old bushings, place in new ones and do your final torquing with the wheels on the ground.