rear diff oil

[andycook]

Changing oil on my 96 uk 4runner. Have done engine and going to do gear box, transfer box and differentials.
But - the rear differential is a limited slip (LSD) type?
It says nothing about this in the Ozzy Haynes manual i have.
But i know for the MkI shogun I used to own, you did needed special oil in order for the LSD to funciton properly?

cheers
andy

[Gamedawn]

An ordinary mineral gear oil is not suitable for lsd's but I use Redline synthetics and their standard gear oil works in lsd's as well as ordinary diffs. This may be true for other synthetic gear oils as well

[andycook]

the limited slip function aint working on it... I tried the drive-off-a-jack test, didnt work, the raised wheel spun. Its defintely an LSD diff as it has a sticker saying LSD oil only.
So either its bust, or had the wrong type of oil in past. The trucks done 138,000.
Is it a big expensive job to get it working properly again?

[Tallyman]

Andy, I read a post on one of the threads on here yesterday (can't remember which one) but someone was suggesting that the LSD is only good for about 50K miles before it needs replacing. Could be yours ain't been replaced. Can't help with the procedure but someone on here may well be able to help out.

[andycook]

thanks - think I read that too. Looks like I will have to replace it then, sounds like big £££ ?
andy

[kite surf]

LSD or not?

I jacked my 97 Surf off the floor the other night, doing a 2" lift.

The Rear Diff i was told categorically would be a LSD....but with both rear wheels high, one wheel spun one way and the other the opposite way?!

Does the LSD revert to this when the plates are knackered or is mine just not LSD? There is a sticker but the markings are indistinguishable!

I was advised to put an additive in, which has been know to cure a Toyota LSD in about 5 miles driving! (from full slipping to perfect)

How does the LSD operate when slipping....as standard?

Anyone.....?

[kevb]

As far as i know lsd (limited slip diff) works like an ordinary diff but if you keep it under power it locks up and works as if you had no diff just straight through gearing.basically locks the diff so that both wheels turn at same speed all the time.diff only comes into play when wheels need to turn at different speeds eg.cornering

[Elvz]

The Toyota diffs are the clutch pack type which means they have stacks of friction disks and spring shims inside. The spring packs push the side gears against the clutches, which are attached to the diff casing. Both side gears spin with the cage when both wheels are moving at the same speed, and the clutches are not operating. When one wheel is on a solid surface and the other is on a loose one the difference in speed locks the clutch stacks solid by applying pressure to the springs until the wheel which is on the solid surface is moving again which releases the locked up clutch packs.

What this means in the real world is that although you can move even though one rear wheel has no traction you can only apply the amount of power to the wheel which has traction that the clutch packs are capable of holding before they begin to slip. There is another variable known as the 'ramp' which is the rate at which the diff locks up to its maximum: steep ramp = short working life. Even a brand new clutch type LSD is usually only able to transmit a small percentage of the car's actual power and the higher the breakaway setting and the more you use it the quicker the friction material will wear out.

Toyota LSD's are not known for outstanding performance anyway and are factory set with a breakaway torque of only 45-50Nm which is ummmm.... not a lot in relation to a 2000Kg car on a muddy slope.

Rebuilding an LSD is tedious but not that expensive if you do it yourself but its not really a job you'd want to do.... In addition to the usual shims, spacers and stuff you need to set up a normal diff you need a selection of clutch discs and spring shims in various thickenesses and lots and lots of time because the only way to set the breakaway torque is by trial and error (otherwise called experience). You can easily double or treble the breakaway torque by adding a couple of extra shims but extra torque means shorter working life; maybe measured in hours and also extra heat which on an off road car can easily boil two litres of oil in a short time.

........And having it done professionally in the UK?

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I may post something about that in the Jokes Section :-)

[Grimreeper]

I have a 3.0TD 1994 with LSD. The motor has 136k miles on it and the diff went. just the clutch plates are about £120 from toyota. I have learnt the hard way. my diff had 5 friction plates but the new ones are a different internal size and now only have 4 friction plates per side. I need to spend more money and alot of time to get it right. Easy way out for me is i have just bought a Detroit Truetrac which is a helical geared LSD so has no clutches to wear out. It costs about £400 from Milner (£335+vat & delivery) and drops straight in. All i have to do is swap the crown wheel. Its uses normal diff/gear oil or LS oil.
After talking to toyota they state even if the oil is to GL5 spec eg synthetics it must also state it is for LSD.....acording to them it will say LSD or LS somewhere on the label.