I have two questions related to a 1 ton rear axle I have under a 1989 motor home. It's a duelly axle.

1) Is the third member interchangeable with other Toyota Trucks? In case I need to change the gear ratio I was wondering if I could swap the entire third member?

2) Is there a way to tell the gear ratio with out pulling everything apart and counting teeth?

 

Jack one wheel off the ground, put the tranny in neutral and parking brake off. Turn the wheel TWO revolutions and count the driveshaft turns. That number is your axle ratio. For better accuracy you could turn the wheel more revolutions - like 20 - and then divide the driveshaft turns by 10

 

1) AFAIK it's interchangeable with all pre-96 4WD trucks/4Runners(79-85 fr/rr, 86-95 rr), and some pre-96 2WD trucks/4Runners(¾ ton & 1 ton usually) with 8" rear axles. Yes, you should be able to swap the entire 3rd member.

2). Find the axle code. Or I can just tell you what the axle code should be. It should be G294(or G292 if it's a 4 cyl.). Which means it should have 4.10s. Since, according to Toyota, all 89 4x2 Cab & Chassis(DRW & SRW) had that gear ratio.