Diff ratios - pickup and wagon

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
Help me out here, some guru.
I am restoring both a 1965 6-230 Station Wagon and a 1965 6-230 Pickup.
The diffs are original.
Do they have the same ratios? Or is the Wagon slightly higher/faster?
 

willys way

Precision Fit
Feb 16, 2011
950
south central Pa
First Name
Tom
Willys Model
  1. Pickup
Willys Year:
  1. 1948
Check your tags on the housing covers. Your wagon might have 4.11 ratio while your truck might have 4.27 or 4.88 ratio.
 

diggerG

Well Oiled
Oct 2, 2011
4,752
Wrentham Ma.
First Name
Greg
Willys Model
  1. Wagon
Willys Year:
  1. 1963
working dog, If they are both flat fender jobs, the SW historically would have 3.54's or 4.10, while the truck used a 4.10 mostly with a higher option (numerically) available. Jeep did not use the same formula as they used with the 6 - 226. diggerG
 

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
Check your tags on the housing covers. Your wagon might have 4.11 ratio while your truck might have 4.27 or 4.88 ratio.

Tags??? Tags ????? You've got to be joking !!! No tags on these little boys!!!
So, how do I do it now??
 

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
working dog, If they are both flat fender jobs, the SW historically would have 3.54's or 4.10, while the truck used a 4.10 mostly with a higher option (numerically) available. Jeep did not use the same formula as they used with the 6 - 226. diggerG

Thanks Digger.
I suppose you might call them flat fenders...but they are the same as every Willys Wagon from 1947 onwards...until they went to the first model Cherokee.
The 'States had numbers of the 1963/4 models left over and shipped them to the factory in Queensland, Australia. And some to South Africa.
By the time they had been converted (RHD) they were released to the public in 1965...hence the 1965 Year designation.

Indeed, only 38 of the Wagons were released in 1965 and I believe I may own the only one left?

It would be nice if I still had tags on them<sigh>

All the best,
Ben.
 

dlj

Sharpest Tool
Nov 16, 2009
309
Wis
Willys Model
Willys Year:
Put a line lengthwise on the drive shaft on the bottom . Mark a line on the sidewall of the tire on the bottom ,or next to the ground vertically. Now count the revolutions of the drive shaft to revolutions of the tire. This will give you a rough idea of the ratio. From what you get you can match it to a known one.
 

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
Does anyone know if I can use a higher (as in faster) diff centre in the truck - simply by changing the centres?
In other words, if I took the higher geared centres out of the wagon (I have a couple of spares) and dropped them into the truck.
Notwithstanding, that the trucks axles are longer?

All the best,
Ben
 

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
Put a line lengthwise on the drive shaft on the bottom . Mark a line on the sidewall of the tire on the bottom ,or next to the ground vertically. Now count the revolutions of the drive shaft to revolutions of the tire. This will give you a rough idea of the ratio. From what you get you can match it to a known one.

Thanks mate. Well done!
Out with the chalk!!

All the best,
Ben
 

Farfrom

Sharpest Tool
All-Star
Dec 14, 2011
250
Troy, IL
First Name
Eric
Willys Model
  1. Wagon
Willys Year:
  1. 1963
Put a line lengthwise on the drive shaft on the bottom . Mark a line on the sidewall of the tire on the bottom ,or next to the ground vertically. Now count the revolutions of the drive shaft to revolutions of the tire. This will give you a rough idea of the ratio. From what you get you can match it to a known one.


I did it this way because I did not see a tag on the rear diff and never bothered looking at the front. I was later surprised to see my front diff did have the tag. Which probably means the fluid was never changed or the PO was diligent about putting the tag back.
 

diggerG

Well Oiled
Oct 2, 2011
4,752
Wrentham Ma.
First Name
Greg
Willys Model
  1. Wagon
Willys Year:
  1. 1963
working dog, there's more to checking your ratio than dlj's method. after you get the number of spins on the pinion gear as opposed to the ring, you double it to get the ratio. For instance about 2.13 turns is a 4.27. And 2.7 turns is a 5.38. The reason is the spiders on a standard differential eat up half the revolutions. To do this method 1 wheel needs to be on the ground. On a Posi the method changes, lift both wheels and count the revolutions of the pinion and that's your ratio. It's harder to lift both wheels on a standard differential and spin, because of the erratic operation of the spiders. I haven't used this method once or twice, but a couple of hundred times, I was the axle identification guy at 2 different salvage yards in a previous century. For me it was actually easier that reading a rusted crappy bent tag anyway. if it was even there at all. diggerG
 

workingdog

Gear Grinder
Oct 8, 2012
10
Willys Model
Willys Year:
working dog, there's more to checking your ratio than dlj's method. after you get the number of spins on the pinion gear as opposed to the ring, you double it to get the ratio. For instance about 2.13 turns is a 4.27. And 2.7 turns is a 5.38. The reason is the spiders on a standard differential eat up half the revolutions. To do this method 1 wheel needs to be on the ground. On a Posi the method changes, lift both wheels and count the revolutions of the pinion and that's your ratio. It's harder to lift both wheels on a standard differential and spin, because of the erratic operation of the spiders. I haven't used this method once or twice, but a couple of hundred times, I was the axle identification guy at 2 different salvage yards in a previous century. For me it was actually easier that reading a rusted crappy bent tag anyway. if it was even there at all. diggerG

Digger,
Thanks mate.
Seeing as you are the axle identification guy, and you're used to salvage yards...did you see my question on swapping the diff centres?
Is it possible?
All the best,
Ben
 

diggerG

Well Oiled
Oct 2, 2011
4,752
Wrentham Ma.
First Name
Greg
Willys Model
  1. Wagon
Willys Year:
  1. 1963
You can change ratios within the Spicer housings, however there is the complication that there is 2 different offsets for the diff carrier, for higher or lower ratios. Typically you can change out ring and pinion sets from 3.92 to 5.38 with the same carrier and lower than 3.92 with the other offset carrier. You would need to bone up on setting backlash with a dial indicator to get it right, which is not that easy at first if you change out carriers. A bearing puller, a big vise and a die grinder would be a help also. Just changing out the ring and pinion still requires some careful measuring, and setting shims. Or find a local mechanic or differential shop to get it right. Lots of shop manuals have differential rebuilding in them. Check out a Spicer or a Dana section and see if you understand it, and go from there. Most of my experience is rebuilding blown plow truck fronts and rears at the truck salvage yards, as well as my own Jeep diff shop business in the 70's and 80's. A little bit of bigger stuff mixed in too. good luck diggerG
 
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