I have a '97 F-250 Heavy Duty 4x4. I bought it used at 20k miles. How do I tell what I have...do I have limited slip diff? what is my gear ratio? I suppose if I had bought this one new then I might have been told this information. I am looking to get some larger tires (35's)...will I need to change my gears? I am fairly knowledgable under the hood but the drivetrain is a little grey to me. I would greatly appreciate any info or ideas.

 

Hey Pastmaster,

Do your codes applies to Expys too?

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Metalgear
Sunny California (except when it rains)
99 Expy XLT 5.4L Stock


[This message has been edited by Metalgear (edited 02-11-2000).]

 

The place to look is inside your door panel, on the label...Most trucks have a 3:55 or 4:10 gearing in 3/4tons. I have posted the codes below, if you have a letter with your code, you have ls

65 4.10. 8250 FORD REG
69 3.55 8250 FORD REG
72 4.63 11000 DANA REG
73 5.13 11000 DANA REG
H5 4.10. 3800 FORD LIMITED SLIP
H9 3.55 3800 FORD LIMITED SLIP
H8 3.08 3800 FORD LIMITED SLIP
B5 4.10. 5300 FORD LIMITED SLIP
B9 3.55 5300 FORD LIMITED SLIP
C5 4.10. 6250 FORD LIMITED SLIP
C9 3.55 6250 FORD LIMITED SLIP
D5 4.10. 7400 FORD LIMITED SLIP
F5 4.10. 8250 FORD LIMITED SLIP

If you don't have the 4:10 gearing, then it would be wise to change to a lower gears. Otherwise, 4:10's might be enough to support 35's. If you do change, you have to change the front diff too...

 

I am sure they do apply. I think the axle ratios are the same.

P.s. I took the numbers from a different site.

 

thanks pastmaster... I just looked and I have the C9 ..... 3.55 Limited Slip. Well I'm glad about the limited slip but will the 3.55 be able to run my new tires (35's) ? And is limited slip worth keeping. I was thinking about an air locker....maybe I should put that in the front axle and be happy with the limited slip in the rear. Any ideas?

 

Good question... Everyone out here runs 35's on lifted trucks, it must be a standard size. 3:55 would be a bit fast for 35's. Most people run 4:56's. It costs a bit to do a complete swap. Around $1400, depending. That is with a locker. I have the Ford locker in both of my trucks, haven't had any problems, but I know the aftermarket versions are better, and will last longer. It all depends on what you want to do.