Interesting 4WD info

[Healewis]

I was passing one of my hand out cards to a woman who has a M reg 4 runner, on B&Q carpark Nelson, and during discusion, I found out that If the oil in the diff has not been changed for a while, you can get the rear end jumping about, around corners, when it's in 4 wheel drive. She said that she took it to toyota and this is what they had diagnosed and since they changed her diff oil, it's been perfect. Mine mucks about a bit in 4WD an I had read somwhere that it was due to the fact that you should only use 4 wheel drive when there's a loss of traction!

[Guest]

I was passing one of my hand out cards to a woman who has a M reg 4 runner, on B&Q carpark Nelson, and during discusion, I found out that If the oil in the diff has not been changed for a while, you can get the rear end jumping about, around corners, when it's in 4 wheel drive. She said that she took it to toyota and this is what they had diagnosed and since they changed her diff oil, it's been perfect. Mine mucks about a bit in 4WD an I had read somwhere that it was due to the fact that you should only use 4 wheel drive when there's a loss of traction!

This would definately be the case with a LSD rear diff however is unlikely to be the case with a standard open diff unless it was really knackered and locking up due to excess play in the gears. Also more important point is that you should not be in 4WD on tarmac otherwise you will get very funny behaviour when going round corners due to axle wind up. Basically the drive train will come under stress and occasionally if you don't break something one or other of the wheels will slip to allow the stresses to be relieved.

Remember that all 1st and 2nd Gen Surfs are part time 4WD only and when in 4WD they are like a full time system with the centre diff locked. This means that all wheels turn at the same speed with no variance in speed allowed when going round corners. In the real world on tarmac the outside wheels on a turn have to travel faster than the inside wheels due to the requirement to travel further, in fact thr front and rear wheels will also travel at different rates and in fact all 4 wheels will travel at a slightly differnt speed. The jumping refered to is basically the wheels slipping to compensate for that difference.

To be honest it sounds like the Toyota garage (yet again) hadn't got a clue what they were talking about. A 1994 4 Runner most likely has a LSD which could explain things but in fact the problems caused by lack of oil causing the intermittent lock up effect would also be seen in 2WD as well.

Cheers

[TonyN]

Yeah, Luckys right, the 4Runner would have had the same problem in 2WD, a jamming LSD is like driving around with a locked diff.

But they should also have told her not to be in 4wd on the road anyway.

Any up to 95' Surf/4Runner will 'muck around' in 4WD if your not on a loose surface. It means the 4WD system is working properly!!!

[humvee]

humvee

Is there a way to tell if a surf is fitted with a rear limited slip diff (apart from jacking up the rear of the car) i.e.are they fitted as part of an upgrade or enhancement pack? Or would there be some indication in the VIN number or other stamped plate on the car denoting such things as paint/trim and options codes? Just wondering..................... ..........................

[Koi]

Yeah, Luckys right, the 4Runner would have had the same problem in 2WD, a jamming LSD is like driving around with a locked diff.

But they should also have told her not to be in 4wd on the road anyway.

Any up to 95' Surf/4Runner will 'muck around' in 4WD if your not on a loose surface. It means the 4WD system is working properly!!!

Mmmmmm only diagnosis here is one of verbal diarrhoea by Toyota again

[TonyN]

Is there a way to tell if a surf is fitted with a rear limited slip diff (apart from jacking up the rear of the car) i.e.are they fitted as part of an upgrade or enhancement pack? Or would there be some indication in the VIN number or other stamped plate on the car denoting such things as paint/trim and options codes? Just wondering..................... ..........................

Most still have the LSD sticker on the rear of the diff pumpkin, its a little white sticker with LSD in big letters on it, sticker is about 1 1/2 x 1"

The Limited option seems to mean LSD in my experiance, but not 100% sure, just every Limited I've seen (apart from 89-90 narrow body ones, Which all seem to be limited's) has an LSD

[Elvz]

If you look on the VIN plate on the firewall you can see the factory code for your transmission e.g. R150F/G145 (on a '89 2.4 Surf)

First character denotes ring gear size. Surf Front diff = F or R (7'5" dia) Rear diff = G (8'0" dia)
Second & 3rd characters denote the final drive ratio and indirectly other information (automatics are fitted with special diffs that are not interchangable with manual ones so they are differently coded)

x06x = 3.889:1
x07x = 3.900:1
x08x = 4.111:1
x09x = 4.222:1
x10x = 4.375:1
x11x = 4.444:1
x12x = 4.625:1
x13x = 4.790:1
x14x = 4.875:1 G145
x15x = 5.125:1
x25x = 4.556:1
x28x = 4.300:1
x31x = 3.909:1
x32x = 4.807:1

Fourth character = number of pinions

2 = 2 pinion
3 = 2 pinion LSD
4 = 4 pinion
5 = 4 pinion LSD

And the bad news.....

The clutch packs in Toyota LSD's last less than 50,000Km even with regular maintainence. After that mileage you need to replace them to restore the limited slip function.