Gear ratio identification

[TxChevyGuy]

Trying to figure out my gear ratio.

14 bolt, 8 lug, semi float. 1994 c2500 with 5.7 and nv4500

No tag on the cover, and these are the only stamping on the tubes

ry8 g353 1205 023427

No build codes on door or glove box so that's not gonna help.

Here's a link to a picture
http://imgur.com/a/aRKsrog

Edit lugs vs bolts

 

[98chevy2500SS]

The best way to do this is to park the vehicle in neutral. Jack up the rear end. Mark the driveshaft with some tape, and mark the tire with some tape. Then count how many revolutions it took for the driveshaft to spin the tire one revolution. If the driveshaft spins about 3 1/2 revolutions, then you've got 3:42s. If it spins 3 3/4 revolutions, then you've 3:73s, so on and so forth. Most likely you will have 4:10s, since its a 3/4 ton, but that's just me guessing. The test I provided will give the true answer.

Hope this helps you.

 

[PlayingWithTBI]

8 bolt. 1994 c2500 with 5.7 and nv4500

Hmm - 8 bolt, do you mean 10 or 14 bolt? That's the number of bolts holding the ring gear to the carrier, a lot of people think that the number of bolts on the rear cover designates this ID.

 

[98chevy2500SS]

In his picture on Imgur, the description says its a 3/4 ton 8 lug 14 bolt SF.

 

[TxChevyGuy]

The best way to do this is to park the vehicle in neutral. Jack up the rear end. Mark the driveshaft with some tape, and mark the tire with some tape. Then count how many revolutions it took for the driveshaft to spin the tire one revolution. If the driveshaft spins about 3 1/2 revolutions, then you've got 3:42s. If it spins 3 3/4 revolutions, then you've 3:73s, so on and so forth. Most likely you will have 4:10s, since its a 3/4 ton, but that's just me guessing. The test I provided will give the true answer.

Hope this helps you.

Tried that. Gave me 1.75ish pinion vs tire. Maybe because only one tire was off the ground?

Hmm - 8 bolt, do you mean 10 or 14 bolt? That's the number of bolts holding the ring gear to the carrier, a lot of people think that the number of bolts on the rear cover designates this ID.

Yeah. 14 Bolt, 8 lug. Fixed it in the orginal post. Been up for 20 hours.


This is the first axle that I tried to figure out the ratio. In my Jeeps I was installing lockers so gears got replaced anyway.

 

[98chevy2500SS]

Not sure if it matters if one tire is off the ground or both. You could try with both tires off the ground and see if that makes a difference. It should've spun more than 1.75 times.

 

[TxChevyGuy]

I will give it a shot tomorrow. I re checked it probably 6 times. Even had one of my kids under it counting it. I couldn't believe it. We will try and lift both tires off the ground.

 

[PlayingWithTBI]

Or while only one tire is off the ground (the right side one), rotate it one full turn and see how many times the drive shaft turns.

 

[kennythewelder]

Here you go, this is how you do it.

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[TxChevyGuy]

Sweet!!! I will turn it 10x. More precise than turning 1 time.