Gear Ratio

[ksquare84]

I know there’s a ton of posts about this but I’m having some trouble figuring out the gear ratio. This is what I see on the ring gear on my 1984 GMC k2500 Base

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[nvrenuf]

Looks like 41/9 which is 4.56.

Btw, that gear oil looks NASTY.

 

[ksquare84]

It was horrible hasn’t been changed in 30 years and hasn’t been on the road in 22 years.

 

[bucket]

Looks like 41/9 which is 4.56.

Btw, that gear oil looks NASTY.

Yep, looks like moisture got to it.

It's worth paying attention to where the diff vent is placed. On one of my trucks, rain water would run from the bed and onto the frame. The water would then run under the top flange of the frame (much like a roof without a drip edge) and run right into the diff vent that was wedged up against the inside of the top frame flange. A minor repositioning of the diff vent took care of that issue.