I was curious if anyone could help me out in finding the overall crawl ratio of my truck. I have a '90 F150 5spd 302ci Reg Cab LB, I believe that the rearend has 4.10:1 stock but as for the T-Case and first gear in the tranny I have no idea. Correct me if I am wrong but don't you multiple all of the ratio's by themeselves for example a truck with 3.55:1 axle gears, 2.0:1 T-case and a tranny first gear of 3.3:1 would have a crawl ratio of 23.43:1. Any info at all is appreciated

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1990 Ford F150 XLT Lariat 4x4

5spd
5.0L 302ci
K&N Filter Charger
Hedman Cat with MagnaFlow muffler
Tint
Rhino bed and undercoat lining
100 HC AudioArt Amp w/3 12" Impulse behind the seat

 

edit

[This message has been edited by max mitchell (edited 06-03-2001).]

 

i believe you are correct, just multiply all of the ratios . . . .

 

Yes just multiply the three #'s. A crawl ratio of 23.43:1 is not all that good. According to a sorce I read a 85.1-125.1 is suitable for most offroaders. A few things to to keep in mind.
1. Bigger the motor, less crawl ratio you need.
2. Low ratios are good for rocks, higher ratios are good for mud and sand
3. You can usually run a higher crawl ratio with an AT than MT transmission

IMO, I think the 23.43.1 would be close to what is in my truck and it seems plenty low enough for me. Does anyone know the T-case and AT ratios for sure?

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97 Ford F150 XLT 4x4 4.6L auto, Std cab/Long bed, 3.55LS rear axle, PW,PL, and PM, captian chairs w/arm rests
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KYFordFreak,

My crawl ratio is 36.55:1 Yours should be around 26.6:1 depending on your tranny.

Regards

Jean Marc Chartier

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Thanks for telling me. I have the AT trans w/OD (which trans is this? 4R70W?). Can you tell me the exact ratios of my tranny and T-case. I think they say that 3rd should be about 1to 1 and OD is something like .71. I have heard that the 4R70W is something like 2.84:1, but you have to also consider the torque convertor has a big effect on this from a standstill (starting out like 7.84:1). Correct me if wrong.