Jap import diff ratio

[Olazz]

If you own a Japanese import, HDJ81 you may be interested to know that ALL Japanese 80's came with a different diff ratio to the Euro model.

Euro model manual 3.7
Japanese model manual 4.1

This is the same ratio as the UK Automatics.
Your build plate will confirm which ratio your vehicle left the factory with.

 

[karl webster]

I found that in the past Lazz when a guy wanted me to get him a ring and pinion.

 

[Olazz]

Didn't know that myself Karl and was under the impression that all manual 80's had the 3.7 diff and auto's had the 4.1.

Was told to count the teeth on the cogs to determine the ratio, until I wrote to Toyota who gave me the information.
Also explained how to decipher the build plate info to determine ratio.

Every day's a school day !

 

[karl webster]

True mate. We never stop learning. I know yours is the manua as the guys was that I got the bits for. Do you know if the auto versions are running the same ratio as the uk autos as well then or do they have another ratio?

 

[Olazz]

I don't Karl, buts its easy enough to tell from the build plate.

Long numbers at the bottom of the build plate will include letter "K" followed by 3 numbers. The first 2 (probably 29 or 30) will indicated the ratio and the last digit will indicate the type of diff.

********K295**** 4.1 ratio with LSD
********K294****4.1 with locking diff

K30 is 3.7
K28 is 4.3

I have a long list of the various codes if you need more info.

 

[karl webster]

Thanks Lazz.

Ill have a look at a coulpe

 

[StarCruiser]

Great, thanks for this, I now know I have a LSD in my rear axle. I don't know much about them. I'll have a search on here as I'm not aware of any benefit from mine. Pretty sure I've been cross axles and struggling before now.

 

[wobbly]

If you're not sure if its working, jack up the rear and spin one wheel, the other should spin in the opposite direction if the lsd is working. If they both spin in the same direction its not working.

They do wear out, on the Prado the lifespan is apparently about 100,000 miles.

Pete

 

[StarCruiser]

Thanks, I have done this and I know that they turn in opposite directions. I even had the whole truck off the ground once with the wheels turning slow to try and work out why it would shimmy down the road at low speed (two big bulges on the rear tyres was why) and could stop one rear wheel and let the other spin. Guess it's time for a rear axle rebuild now I'm doing the front one. [emoji53]

 

[uHu]

Stumbled over this axle codes sheet:

 

[StarCruiser]

Is it the case that if your rear diff is identified as K295 with 4.1 ratio, that your front diff is also 4.1 ratio? I can see the codes list shows that the front is preceded by an 'F', however I cannot find such a code on my VIN plate.

 

[Olazz]

Yes both will be the same

 

[iceman]

Star you doing the refurb yourself or getting it done?

 

[StarCruiser]

Not given it much thought yet iceman, I will probably at least look at the rear LSD myself and either rebuild or fit an ARB air locker depending on costs and what capability I want to end up with.

 

[StarCruiser]

LSD exploded diagram. Plates (6) kit over £300 from Toyota. Under £9 each from Amayama.

 

[Iwan]

If you think the springs are weak.. which can affect how soon the lsd activates. You can pack them out with washers to make the lsd more sensitive and activate sooner. A bit of a tip!

 

[warrenpfo]

I always thought that ARB dont make a diff lock for the LSD diff housing as its different in shape to the std diff housing or the UK spec locker diff housing. Do you know otherwise??

 

[Olazz]

I always thought that ARB dont make a diff lock for the LSD diff housing as its different in shape to the std diff housing or the UK spec locker diff housing. Do you know otherwise??

Yep I've got ARB lockers in my LSD.

 

[StarCruiser]

Yep I've got ARB lockers in my LSD.

Nice, I had a little panic there for a minute.

I did wonder about spring adjustment or even replacement. That thought stopped me ordering the bits without first inspecting the diff.

Good info guys.