crawl ratio?

[bigsliks]

Can someone help with me with the stock crawl ratio of my 91 xj automatic and np 242.

what is first gear ratio?
what is 4 low ratio ?
and I know my rear end is 3.55
and if I was running 31" tires

what would my overall crawl ratio be?

thanks

[jeepdude10000]

Ok if i'm right

first gear ratio - 2.804
4 low ratio - 2.57
rear end - 3.55
tires - 31

overall crawl ratio = 25.58

[Littlewhitexj]

isnt 4 low 2.72:1?

[jeepdude10000]

isnt 4 low 2.72:1?

i belive 2.72 is NP321

[5-90]

NP321? They've come out with a 3-speed case? Cool!

For both the NP242 and NP231, low ratio should be 2.72:1. I know it is on all the boxes I've got, and I've got both handy...

5-90

[jeepdude10000]

first gear ratio - 2.804
4 low ratio - 2.72
rear end - 3.55
tires - 31

overall crawl ratio = 27.08

[bigsliks]

OK thanks guys

[Menzenski]

jeepdude10000 is mostly correct, but I have two things to add:

1. The tires have nothing to do with the crawl ratio.

2. The torque converter in an automatic is said to double the torque, so you could say that the crawl ratio is more like 54:1.