Gear ratios

[lowedawg20]

I have a 93' K1500. I am wanting to go to lower gears. How can u tell what gears are in them now?

[2000CAYukon]

Look at the SPID Sticker (Glove Box) and Google all of the codes that start with G and you should find your gear ratio.

//2000CAYukon

[lowedawg20]

Thanks, but the sticker is faded out. I cant hardly read it

[2000CAYukon]

Since the sticker is faded, the best way is to count the number of teeth on the ring gear divided by the number of teeth on the pinion gear. You can also rotate the rear tires one revolution and count the number of times the drive shaft rotates.

My 90 K1500 came with 3.73 gears.

//2000CAYukon

[lowedawg20]

Thanks for the info Yukon. I will try the rotation thing again. I tried it once but didnt feel like it was accurate.

[Z15]

A little more about the truck.
Body style
Engine
Trans

Most V6 and 5.0L V8 engines in reg cab will be a 3.42, e.cab with Z71 often have the optional 3.73's. Non-Z71 optioned trucks rarely have a 3.73. Some years the default ratio with the Z71 option was 3.73 but this is not always true. If the stock tires on the door placard are anthing but 265's, 3,42 is most likely what the ratio is. 3.73 was a no cost upgrade.

Rare to find a 4.10 in a 1/2 ton


btw

If you are changing gears and you have a 4x4, you must change both the front and the back, they must both be same ratio.

[2000CAYukon]

I should have posted that my 90 is a Z71 Short Bed Standard Cab with 3.73 gears.

//2000CAYukon

[lowedawg20]

The truck is a reg cab 4x4, no Z71 with a 350, automatic. It has a 3'' lift and im running 33x12.50x15's. I tried the rotation and Im only getting about 2 turns of the drive shaft for the tire to make a complete turn. I need lower gears for sure. At least 3.73's.

[Z15]

You are not going to be able to figure ratio without the original size tires.

The Bigger tires are giving you an incorrect answer. Larger tire, bigger circle and less turn complete turns.

With those size tires, 3.73 is still not going to cut it. 4.10 and the big tires will equate to around a 3.73 ratio.

[2000CAYukon]

This chart may give you an idea of what your current gear ratio is http://www.4lo.com/calc/geartable.htm If you use D instead of OD at 65 MPH it may be close.

//2000CAYukon