How to determine Axle Ratio.

[Ragingbull]

I have looked at the rear axle and there are no tags to be found. I'm trying to determine the rear axle ratio,model etc on my 84 Winnebago Chieftain. I can't find anything via the VIN# to help either. Any ideas?

[Outlaw45]

look to see if you have a weight tag to see what your gross is. it may be there. also are you running gmc stuff or what?

Outlaw

[Ragingbull]

Quote:

Originally Posted by Outlaw45 look to see if you have a weight tag to see what your gross is. it may be there. also are you running gmc stuff or what? Outlaw

Yep Chevy Chassis. P30/32. GVWR is 11,800 lb. Looks like there was a tag under the hood that was riveted on at one time long before I became its owner.

[Outlaw45]

i beleve it's a 4:10. i think that is what mine is. any reason other then just wanting to know? do you have the 454 in yours? probly does. i only get about 7 mpg out of mine. if i decide to keep it i'll hot rod the dist. and carb and do a couple of other things to see if i can get 10mpg out of it.

Outlaw

[TXiceman]

A crude method to approximate the axle ratio is to take a string and mark and tape it to the bottom of the drive shaft. Run the string out to the side. Now mark the bottom of the tire at the center line. Now drive it forward with some one watching the mark on the tire and have then tell you to stop after one revolution of the tire. Shut down the rig and set the emergency brake. Now crawl under and mark the bottom of the drive shaft and count the number of revolutions the string is wrapped and estimate the partial wrap. Just over 4 wraps would be a 4.10, just over 4-1/2 wraps would be a 4.56 and just over 5......

For a bit more accuracy, you have the room and some one to walk along feeding string, go for 3 revolutions of the tire and when you count the wraps, divide by 3 for the axle ratio.

Ken

[Ragingbull]

Yep its a 454. I'll give the string method a try.

[RJay]

Here's another method:
Jack up 1 wheel, mark it and the driveshaft. Turn the driveshaft until the wheel has turned exactly 2 revs. The number of turns of the shaft equals the axle ratio.

[HoRotica]

Quote:

Originally Posted by RJay Here's another method: Jack up 1 wheel, mark it and the driveshaft. Turn the driveshaft until the wheel has turned exactly 2 revs. The number of turns of the shaft equals the axle ratio.

This is incorrect. Wheel turn only 1 rev, not 2...

Chris

[ahicks]

Quote:

Originally Posted by HoRotica This is incorrect. Wheel turn only 1 rev, not 2... Chris

That would be true if BOTH rear wheels were off the ground...

[RJay]

Yup, fat fingers, I should have proof read it. Thanks

[RedneckExpress]

Look on the pumpkin. It's either on a stamped tag between the pumpkin cover bolts, or its stamped on the pumpkin housing itself, most times.

When in doubt, climb under and take a couple pictures, always good for confirmation .

A couple axle brand guesses are:

Eaton
Spicer/Dana