Problems With New Gearbox

[huwjones 0]

First, it's actually a 2nd hand 'box, just new to me. Low-ish mileage. I have fitted a TranX LSD to it (I ground down the box casing for it to fit). I have Millers 75/90 gearbox oil recommended for LSD use. Brand new, heavy duty driveshafts.

 

It was initially fine with nothing seemingly wrong after about a 4 mile test drive before MOT. After that I took it for a proper run to get some fresh fuel. 18 miles later I came up to a roundabout and heard and felt a click or thump noise coming from the steering. Got fuel, checked the driveshafts were still where I left them (!) and continued warily. Drove fine, no noises otherwise, even at 80mph on a dual carriageway.

 

So when I got home, got underneath, checked shafts, all OK. I noticed that the gearbox was very warm though. TBH, I've not noticed in the past how warm/hot a box gets. I could't leave my hand on the diff casing, it was that warm. The gearcase was cooler but still couldn't leave my hand on it. Is this normal?

 

So to the other noise: Imagine if you had a very worn CV joint. It's kind of like that. I can only replicate it when you turn the steering very slightly off centre and move the car forward. Even with the engine off, pushing the car, it's as if something is catching in the gearbox. You can feel the shunt (the noise I heard) in the wheels when you move the car.

 

Moved the car yesterday in the drive and I couldn't recreate the symptoms. I can only guess something is getting very warm and expanding, and so catching/fouling on something. Have I ground enough of the casing? I'll try taking the diff casing off tomorrow for a look.

[mikeyd 13]

a plated diff soon shows any wear in driveshafts and suspension joints [as i found out !] i would check outer cv joints and wishbone joints /hub for ovalling as first candidates

[allanallen 528 2 Cars]

Plated diffs clunk, some worse than others but it's something you have to live with I'm afraid. Sometimes in the heat of battle when you lift a wheel with lock and power on it sounds like the box is going to explode!

You've got the wrong oil in IMO. Standard 75w80 is ideal, some folk use friction modifier which helps with clunking but I never have. The oil will get hot, that's part of it's job. The oil sits in the diff housing hence that feeling hotter.

If you haven't ground enough material away the diff will soon of ground any extra away so I'd rule that out.

 

Re MOT, never let them put the front axle on the rollers for brake test. In theory it shouldn't be a problem, in practice it can blow the diff gears to bits.

[huwjones 0]

The only thing not new on the front axle is the hub and bearing, so no wear.

 

I was expecting the diff to be clunky but only on, say, sharp corners. This didn't seem to sound 'right' but I wondered if it was the plates slipping. I've not removed the cover yet but I may leave it a little longer to see if anything changes.

 

Just found the receipt for the oil. Millers competition fully synth CRX 75w90. I was going to flush the oil within 500 miles to get rid of any debris I might have let in during the diff change.

 

Interesting with what you say about the MOT - it went in for the test after the short drive and then the problem has appeared.

I'll put some more miles on it and see what happens.

 

Cheers!

[Tom Fenton 1,526]

Do NOT let them put it on the brake test rollers. Shout bawl fall out with the tester take it somewhere else if you have to.

 

This is what happened to my TranX plate diff

 

 

[allanallen 528 2 Cars]

The diff won't clunk (or you won't notice it at least) under normal use, it's just when you're doing slow speed stuff. Any amount of steering lock at slow speeds will mean the wheels are turning at different speeds, this will load up the ramps and then the plates will slip, release a bit of load and then the plates will slip again, then repeat.... Clunk, clunk, clunk

[Miles 331 1 Cars]

If it's been on the brake tester then it stands a very good chance of being damaged, Good luck with spares now which is why I sold mine

[huwjones 0]

You've got me worried now!

 

What were the symptoms you experienced, Tom?

[pug_ham 241 3 Cars]

Do NOT let them put it on the brake test rollers. Shout bawl fall out with the tester take it somewhere else if you have to.

 

This is what happened to my TranX plate diff

 

 

I wonder if this is what had been done on the TranX diff I've got because it looks a lot like this when I stripped it down.

 

 

 

Need to try to source spares which from miles' post above could be interesting.

 

g

[Miles 331 1 Cars]

Since Quaife have taken them over (As said before the the ATB diff supplier that has the best diff's available buys a plate diff company go figure) parts from what I have been told by quite a few people have very long lead times,

[stu8v 68 1 Cars]

Quaife have always had awful lead times...

[calvinhorse 870]

Mine's a clunker, parking clunk, reversing clunk clunk clunk..

 

But does what it's supposed to do very very well

[dcc 855]

oh the good old clunk, miss it on my car!

[welshpug 1,626]

oh the good old clunk, miss it on my car!

stop taking the bloody thing apart then

[huwjones 0]

I'm very relieved to report that my Tranx is still intact!

 

The oil came out very glittery and non-magnetic, so it had to be fouling the casing. I eventually got the bloody thing out (what a pain in the arse, took longer to get it out of the box than to strip the car!) and noticed a mark on the diff cover. I'd ground the gearbox casing, but didn't realise that the cover needed 'manipulation' as well!

Rain stopped play for tonight. Hopefully get it back together tomorrow.

Is it OK to use standard gearbox oil for a hundred miles or so to flush the alloy particles out?

 

I haven't stripped the diff, but looking into the holes in the casing, I can't see anything abnormal - is it possible to rotate the planetary gears for a better inspection?

[allanallen 528 2 Cars]

I only ever use standard diff oil as do countless other people

[huwjones 0]

Bah, the problem is still in the gearbox. It only seems to become apparent at low speeds for some reason. I'll wait until it blow up or fixes itself!

[camgti 56]

Just to clear up a few things.

 

I have the same diff. If I turn my wheel AT ALL in either direction it sounds like its catching or chattering. Or a chattering whirr. Low speeds, parking etc is when its noisy and chatters and clunks the most.

 

Any speed over 20-30mph is fine. Its the worst when turning out of a junction and you have load on the diff and are not loading it so much to lock it up. Then it can bang and catch and so on. Dont be alarmed!

 

Its not broken, its just a character of the diff. People look at me strangely when getting petrol etc and say. "Mate, your cars making weird noises/ cv are shot mate etc etc".

 

When the oil is cold in the box like when you start the car in the morning (thicker) its not as noisy. As soon as it heats up it becomes noisier and chattery. I had some plate diff oil in it at the start and it was quiet and smooth but SO hard to change gear I swapped it for the normal oil as the syncros would have died in a matter of months.

 

I have mine set on 45/45 ramp angles and find it great!

 

Dont panic.

 

Cam

[huwjones 0]

Many thanks Cam. That's reassuring to hear. Any LSD I've had in the past just clunks when engaging/disengaging. The noise this thing makes had me convinced something was broken. Between that and the new paddle clutch, I was about ready to put the standard stuff back in.

 

Cheers!

[Matteo 17 1 Cars]

Do NOT let them put it on the brake test rollers. Shout bawl fall out with the tester take it somewhere else if you have to.

 

This is what happened to my TranX plate diff

[...]

 

 

Is this an issue even with a Quaife diff. fitted?

Edited September 9, 2014 by Matteo

[Tom Fenton 1,526]

No, the Quaife will be ok in my experience.

[mikeyd 13]

no - my rally car was tested 7 or 8 times with a quaife on the rollers + about 25 tarmac rallys and is still fine [albeit now on a shelf in the garage as replaced with a plated one]

[huwjones 0]

Bah, it seems my diff is goosed. It's making allsorts of strange noises and appears to be getting worse. I'll try to contact Quaife to see if they can assess it.

[Tom Fenton 1,526]

If you want my advice, don't bother sending it them, they will try to change you a ridiculous amount of money just to undo 8 bolts to inspect the internals.

Either strip it and post pictures or if you want I will do it for you.

[welshpug 1,626]

So if they fnd something wrong they fix it under the guarantee but still charge labour?