rear-end question

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Jul 28, 2006 | 10:14 AM

55FordLover

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From: Deridder, LA

rear-end question

The swap is in (1969 ford F100......3.25 gear ratio)....problem is I want posi unit and i dont know what the spline count is....can anyone tell me what that year has so i can get it off of ebay.....HELP!!!!!!!!!!!!!!!

James
1954 Ford F100 302/AOD

Jul 28, 2006 | 10:24 AM

R Pope

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The only way to be sure is to pull an axle and count 'em!

Jul 28, 2006 | 10:26 AM

55FordLover

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From: Deridder, LA

i knew that already but i didnt want to make a mess....come on guys.....HELP me out here....or the pain is coming this weekend.... :-( here is the information from my truck....

F10YDF10209
F10 = F-100
Y = 360 V-8
D = Dallas, Texas
F10209 = Built in May, 1969 and 10209 truck built.

115 = 115" wheelbase
M = Wimbleton White
F-100 = F-100 1/2 ton
2381 = Light Blue Interior and Conventional Cab
G = Automatic
17 = 3.25 9" rear axle (Too bad it didn't say A-1 then it would be a limited slip)
05000 = 5000 GVW
175 4000 = 175 HP @ 4000 rpm
61 = Built in Dallas, Texas

Last edited by 55FordLover; Jul 28, 2006 at 10:39 AM.

Jul 28, 2006 | 04:02 PM

rogerf100

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From: Owasso Oklahoma USA

I pulled a similar axle out of a 68 F100. It is a 3.25 ratio and it had 28 spline axles. Do you have the tag from the axle? The one on mine reads

WDM-S 9LA
3.25 9 313A

Jul 28, 2006 | 04:28 PM

mtflat

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From: Kalispell, MT

Quote:

Originally Posted by rogerf100

I pulled a similar axle out of a 68 F100. It is a 3.25 ratio and it had 28 spline axles. Do you have the tag from the axle? The one on mine reads

WDM-S 9LA
3.25 9 313A

I'm not sure what you're asking for. I've never seen a list of vehicles that had which spline counts or limited slip diffs in them (posi is a chebby term, btw)

Pull your axle and count the splines - it's a 20 minute job and the only way to know for sure.

Axle tags will tell if it's a ltd slip - look for 3L25 9 (the L replaces the decimal point in the ratio)

Jul 28, 2006 | 07:59 PM

55FordLover

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From: Deridder, LA

thanks for the help gents....i guess the hardway is going to pay off in the end....20 minutes....hmmm.....by myself....make it 40, a beer and some good music!!!!!!!

Jul 28, 2006 | 08:55 PM

3Mike6

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Joined: Aug 2003

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From: Oakdale,Ca.

Heck ya...unless you know the rear to be as it came frmo the factory, many things could have been changed in the last 35+ years.

Heck, I've got a near original 36 PU...with a '55 Chevy rear under it.

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Jul 29, 2006 | 12:25 AM

imlowr2

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From: Santa Clarita

Most of the production cars came with the 28 spline rear end. High performance vehicle such as the Shelby and special Cobra models came with the 31 spline. The 31 spline was designed for racing purposes and is a much stronger than the 28 spline. You can also tell by the shaft on the axle. One is straight and the other has a taper. I believe some of the Jeep vehicles or offroad vehicles came with the 31 spline also. When getting a new posi unit, make sure the yoke( the part the U joints attach) is the same as yours, otherwise, you may need to get new U joints/ caps. If your interested in selling the 3.25's let me know.