Clunking noise/feel pulling off and turning

[MrT]

Hello esteemed fellow MR2 enthusiasts.

My '05 MR2 has progressively developed a clunking sound & feel when pulling off and turning more than just slightly (ie differential working). It is louder/harder under greater load, and can be made out from 2nd gear also but not as pronounced and  higher frequency. Again suggesting the differential. I am rather aggressive in launching and driving the car, alot of roundabouts and stop-start traffic too.

Can anybody advise what this might be. I suspect from the load and turning variations that it is a clutched LSD problem. I changed the gearbox oil before summer and it seems to have been developing since then but I can't confirm a correlation to that event. I don't exactly remember which oil I used but it was advised on the forum and elsewhere though I have a faint concern there was mention of issues with clutched LSD for someone, I think it was GL4 from Halfords.

Can anybody advise how I determine what led my transmission has also, or if a Torsen/helical differential might make these symptoms and why?

Thanks in advance.

[MrT]

PS, I've searched the forum with very little information but I might not be asking the correct questions...

Thanks again.

[Carolyn]

It does seem to be too much of a coincidence that the oil change coincided with the surfacing of the 'clunk'.

I've been told that torque sensing diffs (which we have in these cars) are quite sensitive to lubrication issues.  (Never had the problem myself, though.)

I CAN say that I have been using Redline MT90 as recommended on here by others and I've not only had no issues but both gearboxes are quiet and very smooth to operate.

Not cheap, though.  It's £40 to find out if it makes a difference!

[Bossworld]

I was trying to search for confirmation of our LSD type (I'm sure someone told me it doesn't need LSD specific gear oil because it's a sealed unit, but that could well be apocryphal).

Came across this person suffering LSD clunk - https://www.mr2oc.com/61-3sgte-turbo/459857-gear-oil-93-e153-w-lsd.html#/topics/459857

[jonbill]

I'm pretty sure it's a helical ATB, so no clutches so OK with ordinary api gl5 I think.

[Carolyn]

From Toyota:

http://media.toyota.co.uk/2002/09/mr2-roadster-%E2%80%93-2003-model/

It's a torsen. 

[1979scotte]

From Toyota:

http://media.toyota.co.uk/2002/09/mr2-roadster-%E2%80%93-2003-model/

It's a torsen.

Difficult to argue that one.
Although I don't suppose the press releases written by someone that really knows what they are talking about. 

[MrT]

Thanks folks. I looked through the Wikipedia page on c series gearboxes and there are both helical and clutched options/possibilities. So I'm unclear what I have. It feels like a clutched diff slipping as I turn and tension builds. The tyres definitely aren't slipping or chirping so it's in the box.

Carolynne, I'll look at changing the oil again, might through some zx1 in there also. The gear changes have gotten tight over the same period also. So I'm suspecting the oil.

I was going to pack this box in and do a diff swap of my c56 torsen LSD (JDM) into a corolla 5 speed with longer ratios for cruising. I almost NEVER use 5th, exceeding speed limit in 3rd and even staying below 4k (out of vvti range) I'm over the limit in 4th... No use for 5th. And I could use a few less revs when cruising, anything over 2500rpm is plenty. The Corolla box will give me ~2750rpm at 70mph.

Thanks for the help folks.

[jonbill]

This is the diff from a standard UK car, fwiw.

[MrT]

Ok that's definitely helical. I'm going to change the oil and see what happens. Just a pain filling it again but I've practiced now...

[MrT]

PS, how much oil do I need?

[Carolyn]

all of 2 quart bottles MT90.  Just right.

[MrT]

Great thanks Carolynne.

[MrT]

Strangely the car hasn't been doing much of any juddering or noises. I must assume my winter tyres flex and give more and allow a bit of slip so not building up torque in the diff...

That seems sensible right?

[Ardent]

I know this is an lsd based question.

But the perception of
"staying below 4k (out of vvti range)"
Is not correct.

[K T M Rider]

Ok that's definitely helical. I'm going to change the oil and see what happens. Just a pain filling it again but I've practiced now...

I used a mini transfer pump like the one in the link below to change mine, loads better than a funnel (if you don't already have one)

https://www.ebay.co.uk/itm/HAND-TRANSFER-SIPHON-SYPHON-AIR-PUMP-FUEL-OIL-WATER-DIESEL-FLUID-EXTRACTOR-NEW/282764747053?epid=26011081000&hash=item41d617a12d:g:G64AAOSwH-daKlr7

[Carolyn]

Nifty pump!

Or.

Jack the back of the car up good and high.  Remove the redundant plug/cover thing that fills the hole for a speedo drive we don't use, (Just above the diff).  Pour the oil in there.  Put the plug/cover thing back in before jacking down.

(If you don't jack it up the oil will overflow.)

[MrT]

Ah thanks Carolynne, handy tip.

[MrT]

I know this is an lsd based question.

But the perception of
"staying below 4k (out of vvti range)"
Is not correct.

Yes I know, simantics really. Just mean out the power band, in the torque curve, however we describe it, economic review range.