I have a 9" Ford Diff out of a 65 Ford 1/2 ton truck, its a 28 spline. When I had it diss***embled I discovered that it has 2 axles that are the same length. I have never owned a 9" before so I dont know if this is common, but I was under the impression that they should be different lengths, like how an 8" is and such. Any rear i have worked on before has different length axles in it unless it was narrowed or something and this one wasnt narrowed. Can anyone shed some light on this and let me know if I should be seeking out another axle? I have been told it came from a driving truck, but something doesnt seem right to me regardless. Thanks guys.
Yep, some are equal length, saved Ford a few $.01 to use all one length, makes the pinion slightly off to one side, but in a truck with a long driveline, it was not a problem....later trucks and cars do not have equal length shafts....there are TONS of different 9" out there in TONS of different configerations....I have seen several that many say never existed....Ford was good and making left over parts work in what ever....so you never know what you might find....
So is that the equivalent of 2 long axle shafts then? Since to look at it you can see that it has different length axle tubes externally is what had me thinkin that the axles should be different lengths as well??
the differential is offset inside the pumpkin, so when the tubes are the same length, then the axles have to be different lengths.
I'm in the middle of trying to find a Ford 9 inch as well. Could someone else confirm that it may be a shortened rear end using two short axles. I'm still trying to figure out how that would still work but others have told me that it can be done.
Ford pickups with a 9in 60-67 68-72 and 73-86 both axles are the same length. Ford vans are different lengths as well as early broncos 66-76 if this helps.
look at a 9" diff, and think about how long each axle has to be if the pumpkin is centered in the rearend housing.
Just another side note, a 2" offset pinion will have equal length axles and a centered pinion will have axles with about 4" difference in length.
Any chance that you know a truck app. (5x5 1/2) that has a centered pinion? I need one for a short wheel base. Gary
Wow...you guys are really getting too far into the details on tube length, axle length, pinion issues! Don't bother to look for a mathamatical formula to it all...it isn't there! Ford used whatever parts and offsets were required to handle a specific job and be cost effective. The combos are endless. Ford diff units have a large offset for the spider gear cross shaft...axles were mixed and matched to come up with a useable track width to match the required job. A centered pinion isn't usually needed unless the offset is REALLY radical or the driveline is super short. 2" or 3" offset isn't radical. Pinion angle and trans output angle being compatable is more important. the pumpkin itself being centered is much better looking from the back than having it offset to get a centered pinion...
If you are lucky enough to go thru some old Hollanders you will find some serious info on axle lengths, especially ones with the 4 1/2" pattern. It makes narrowing a rear fairly simple if need be by just cutting the tube and plugging in the right length axles. Another trick is for those F100 owners who want the same bolt pattern as their M11 front. Both right sides from a 77-79 TBird/Cougar and a few others will plug right in. I contributed to the research for an FTE article a few years ago, it is still in their tech section. Includes bearing and backing plate info also.
The Jalopy Journal
