Differential ratio?

[Nhaz]

Howdy peps. I managed to take the front end off my donor truck and put in on mine. Mine is a 1992 and the donor is a 1991 I think. I knew right away that it was possible they had different differential ratios. And I was right. So I need to match ratios.

But I don't know what the donor trucks ratio is. the tag is pretty much illegible.

So wrote down the vin from the donor truck. I don't suppose it can be translated into a ratio number for me?

1FTCR15X0MPA52952
----------^
could be a zero ?

 

[feellnfroggy]

I googled this--->

front diff gear ratio for 91 ford ranger

and found this------>

Ford Ranger Dana 28 and dana 35 TTB AxlesIn 1998 the Ford Ranger went to a Dana 35 IFS front axle. ... The above mentioned code would indicate that the axle was a Ranger axle built in 1991. ... the back side of the right axle beam that lists the year manufactured and gear ratio. ... In the (2) photo's on the right you'll see a true Dana 35 differential. ...
www.therangerstation.com/tech.../4wd_Front_Axles.html - Cached - Similar

 

[Nhaz]

yah i saw that it said 3.73. I am fairly sure my existing rear diff is 3.73. but my engaged 4x4 tells me from moving the truck 2 feet on dirt from the shudder the ratios got different from that picture.

 

[feellnfroggy]

4 hi or 4 low? 4 hi can be used on improved surfaces, but 4 lo is recommend only in extreme slip circumstances. (wet grass, lol mud snow etc.) Our humvees jerked around like that in 4 lo as well. But you could legitamately have different gear ratios, not from the factory though.

 

[Nhaz]

I double checked my ratio on my rear axle today and it appears I was wrong its not 3.73 the axle is 3.27. reading it upside down my have made me read it wrong the first time =>

So yes the front I put on is 3.73. Now the next project is finding a 3.73 limited slip rear.

 

[feellnfroggy]

Where did you get the front from? It will prolly be easier to find a factory front with 3.27's than a rear with 3.73's, until at least you can afford gears.

The other option is find a junk 99 4x4. Some of these came with 4.11 from Ford.

 

[Nhaz]

The 3.73 front is off my donor truck I have the rear to go with it. I am going to see if I can read its tag so as to find out if its limited slip.