Gear Ratio

[Coadster32 793]

I read somewhere recently in Red Square that the rear ends on a 551 Suburban are 108 to 1. If that's true, It should only crawl in first gear. What are the true ratios for the gears in the uni-drive? :hide:

[Michael Bullington 5]

Unidrive

1st Gear 66.8 to 1

2nd Gear 42.4 to 1

3rd Gear 24.6 to 1

Reverse 51.5 to 1

Low Range

1st Gear 267.2

2nd Gear 169.6

3rd Gear 98.4

Reverse 206 to 1

[Coadster32 793]

Wow, that was fast. Ask and you shall receive. Thanks. 108-1 didn't sound quite right. How about the transfer from the motor to the unidrive? I understand it depends on the pully sizes, but lets say that it's all stock.

[TT-(Moderator) 1,128]

They have a 2

[Teddy da Bear 11]

Ok.....gotta stir the pot (mainly out of ignorance...lol)

I have noticed in all of my 8 speed transmission tractors

that 3rd gear, lo range is slightly faster than 1st. gear high range.

(B-80, B-100, C-100 & Raider 10)

Would that not put the ratio number in between 1st and 2nd gear

ratios of the high range like 50 to 1 instead of the 98.4??

Would it have anything to do with having 10 pinions instead of

the normal 8? (which I do not know what I have).

[sorekiwi 761]

1.6 x 68.8 = 107:1. Pretty close to the number you were told...

TDB: Differential internals only affect the relationship between the two axles, they dont affect the overall transmission ratio.

[Coadster32 793]

That's alot of power at the wheel. I'll give it a go plowing tonight. I just put on a set of 55lb weights each on my 551. Thanks for the tech stuff. :hide: