rear diffs

[tilly1]

need a little help , i have a lj70 1990 2.4 and the rear axle /diff is badly corroded so i have found a second hand one from a lj78 without electric locker , so like mine , what i need to know is will it be a straight swap ratios are they the same etc , thanks

 

[Roger Fairclough]

The LJ70 uses the 8" diff. I believe the 78 uses the same diff. but a different axle casing to suit fully floating axles and maybe disc brakes. I can't guarantee though.

Roger

 

[Ben]

Their is a good chance the diff ratio's will be different. Presuming your LJ70 is a manual and the LJ78 is an Auto?

I've never seen a manual LJ78, theyve all been Autos.

I dont think their fully floating axles though?

When I bought a set of LJ78 axles they looked the same as my LJ70 ones, just they had disc brakes.

The axle should bolt straight on, and will be a nice upgrade to rear disc brakes, but I think you will have to fit your diff, because I think the ratio will be wrong.

You can check the ratio roughly (without stripping the axle down), by putting a mark on the top of the input flange on the diff (bit the prop bolts to) and put a mark at the top of the disc/drum brake.

Then count how many times the disc/drum turns for one rotation of the input flange.

 

[tilly1]

thanks chaps

 

[Roger Fairclough]

If it has discs at the back it will have fully floating axles. This set-up prevents any chance of the disc moving axially and increasing pedal movement.

Roger

 

[Chris]

Will the new casing accept the locker? I thought the profiles would be different. Isn't there usually some sort of 'cut out' where the motor bolts on. Course if you don't need the locker it doesn't matter.

Chris

 

[Ben]

The way I read it was that Tilly doesnt have a locker, and nor does the new axle?

 

[Chris]

Ahh, yes that rather does depend how you read it Ben. I think you are right. I just wouldn't have mentioned the locker in that case.

Even if the diff don't swap directly, I'd presume that the R&P would?

C

 

[Ben]

Yes I'd have thought so Chris. As there both 8" diffs.

 

[tilly1]

diff

your right ben , no lockers on either mine or the prado diff

 

[wobbly]

The 78 diff *may* be a lsd as they were an option, would be a result if it was.

Pete

 

[Rich Sims]

If it has discs at the back it will have fully floating axles. This set-up prevents any chance of the disc moving axially and increasing pedal movement.

Roger

my kzj78 with rear disc doesn't have a floating rear axle!

 

[Roger Fairclough]

Then you must have a "semi-floating" type. In this system the half shaft rotates inside a roller bearing at the hub end and is located within the diff by an "axle shaft lock". The back of the diff has a separate, bolted on, cover.

Roger

 

[Rich Sims]

No it's not floating at all, same set up as the drum brake version.

 

[Roger Fairclough]

How very odd, the manual only shows a drum brake fitted onto the 8" light duty axle.

Interesting though.

Thanks for the info.

Roger

 

[tilly1]

thanks lads , great trucks , thinking of maybe a 90 but they just dont seem to be as tough as the 70 series mmmmm

 

[Roger Fairclough]

The 90 has it's points but for serious articulation the IFS is not as good as a coil sprung beam axle. That said, a guy in Australia has just completed a beam axle conversion on a Surf. Must rad about that.

Roger