Topic: What differential gears?

[blackdiamond]

My buddy recently got a 1981 Toyota truck as part of a house deal.  It is missing the rear 3rd member and today I was trying to help him determine, without taking it apart, what type of differential and gears is had.  It seemed to have an open differential, but the driveshaft only turned about 2-1/4 turns for one revolution of the wheel.  I am expecting that it has stock 3.90 gears so what am I dong wrong?  I performed the same check on my 85 with 4.88 and it check out perfectly.  I tried it with both wheels in the air and then again with only one side in the air.  What am I doing wrong or does anyone have any ideas what is happening?

        

[kneedownnate]

I think most 81s came with 4.11s.  Get me the code off the firewall tag and I'll let you know.  Should be G082 for 4.11, G072 for 3.90 and G102 for 4.37.

[blackdiamond [OP]]

There was an article in the November issue of the 4wheelparts.com magazine that said the 1981 was 3.90 and the 4.11 started in 1982?

[Rocksurfer]

80 4.37   

81 3.90

82 4.11 



.........I think

[Duffil]

put the truck on the ground.
push the truck one tire revolution while counting driveshaft revolutions.
easy.

[blackdiamond [OP]]

put the truck on the ground.
push the truck one tire revolution while counting driveshaft revolutions.
easy.

Does it not work with open differentials with both tires in the air?  It worked fine with my truck, maybe the limited slip has some affect? 

[Duffil]

yes, you CANNOT do it in the air if you are open.  Locked or limited slip is ok.

[blackdiamond [OP]]

I think that this qualifies as my one new thing learned today, thanks.

Here is the truck information:

Model: RN38L-KDA

489LU41G072L45

It looks like G072 is 3.90 gears and L45 is a 4-spd transmission.  What else does it mean?

Does anyone have access to Carfax if I sent them a VIN number?

[kyle_22r]

look in the 4x4wire toyota tech section. there's an article about getting the info out of your model #.

i've been bitching on the 4x4wire forums to change some stuff in their tech section because it's dead wrong.  mainly like saying that '79s had 4.10 gears, and that power brakes became standard in '81 or something.  '79-80 had 4.375 gears, power brakes were standard in all 4x4s and i think 2wds from at least '79(i've never even seen a hilux from the late 70s with manual brakes) etc.

i think that 4wheelparts mag copied their info off 4x4wire, because it's the same and it's wrong.  get your damn facts straight, people.  then again, what can you expect from a magazine that mainly caters to jeep people...