Whats in my REAR!?

cuzza_wa
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Joined: November 20th, 2017, 2:54 pm

Whats in my REAR!?

Unread post by cuzza_wa » June 18th, 2018, 5:38 pm

Hey everyone

Had a few trips in my 4x4 (LN106 hilux) which as roughly 333000km's on the clock, and have a rear LSD that seems to be working...... :crazy:
My compliance plate says its a g285 which i understand is a 4.3 ratio with a 4 pinion LSD.

In a few instances now the rear LSD has worked flawlessly, which speaking to others is strange as they tend to not work very well after about 20,000km from factory.
I thought i would send the previous owner a message and ask him, and he never had any issues with it either, or the owner before him. Apparently its just worked!

To put it into context, last 4x4 trip over rocks the rear end was screwing when cornering like a spool would on bitumen, and also when pulling people out / pulling a large tree (both on dirt) both the back wheels have locked up and started spinning. I know these factory units will only transfer some force, and once that force is exceeded they spin freely, but how can you check that? is there a torque method of determining at what force the LSD "breaks" and would that let me know what kind of LSD it might be?

And is there a check for certain types of LSD's that would tell me if its a factory toyo or something aftermarket?

Any input / guidance most appreciated :)

Cheers, Cuzza

Peter Aawen
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Re: Whats in my REAR!?

Unread post by Peter Aawen » June 22nd, 2018, 10:21 am

Try jacking both rear wheels into the air with the vehicle on firm & level ground, handbrake off, transcase in Neutral, and making sure the front wheels are well chocked to prevent movement in either/any direction. Then, being careful not to get under the vehicle or even too close (in case it falls off the jacks), spin one wheel by hand & watch to see which way the other wheel turns (& how hard it is to turn the wheel!!) Try turning the other wheel too, and tell us what happens.... ;)

If it's only got an open diff (or possibly a totally stuffed LSD), the 'other' wheel will turn in the opposite direction to that of the wheel being turned by hand.... :o

And if you are able to determine that it's NOT an open diff using this method, there are further tests that can show you how much torque any LSD in there takes to transfer drive across to the other side (sometimes even the weakest & most useless but still working a bit LSD 'might' just find enough friction to turn the other side the same way while doing this, but the torque transferred can still be realistically useless as a traction aid); or if it's a 'proper' auto locking diff (which should be more properly described as an auto UN-locking diff!) or if it's a full on 'locked diff' or spool - and you can do all this without pulling the diff centre out! :thumb:
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

cuzza_wa
Been here a while
Posts: 103
Joined: November 20th, 2017, 2:54 pm

Re: Whats in my REAR!?

Unread post by cuzza_wa » July 10th, 2018, 6:44 pm

Yeah its most certainly lsd or more, or it wouldn't of locked up on dirt i would of thought, an open would never lock up :)

Think its time to lift one wheel up, leave one on the ground and see if i can put a torque bar on and break the resistance and see what it breaks at in like lbs/ft increments. Guessing there is a ballpark "force" the factory ones can do and if its a aftermarket the force would likely be a lot higher / not able to break at all.

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