i have a 97 f150 short bed 4x4 with the 8.8 rear with an 3:55's, and i have a 2001 9.75 axle with an 4:88's that i want to put in. do i need to shorten my driveshaft or any other modifications to swap it in? any helpful info would be great. thanks.

 

You got new gears for the front diff so they'll match?

 

yeah by the time the new axle goes in the rear i will remove the front drive shaft to get the truck to the axle shop where their goin to change those gears to 4:88's also, and i see your truck has th 5.4l you have the 9.75 right? if so do you know how long your rear drive shaft is?

 

The measurements were 43 1/8 end to end and 39 1/8 end of yoke to end of yoke. I have a 9.75 rear end, a BW 44-06 MSOF transfer case, and a 4R70W transmission. Don't know how those specs will affect your driveshaft length, but there you go. Hope this helps.

 

thanks, that shold be all i need

 

the only other question is the elecrical plug on the top of the diff will that give the same readings as my 8.8?

 

Per alldata, that is a differential speed sensor for ABS. I would think you should be good.

 

ok cool i wasn't sure what that had to do with, thanks

 

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hey redwood. this may be a dumb question, but what is that? i have never seen that under one of these trucks. do you have a two peice drive shaft? all of the trucks ive been under have the longer wheelbase so they only have one u joint on each end. Thanks! lol

 

It's called a Double Cardan Joint. Just on the other side of it is the slip yoke that goes into the transfer case. It's not what you'd call a two piece shaft. Wiki defines a double cardan as:

"A double cardan joint consists of two universal joints mounted back to back, with no intermediate shaft. The second UJ cancels the velocity errors introduced by the single joint, and so they act as a CV joint."

 

cool.lol learn something new every day! im assuming that you have that because of the short wheelbase on your truck?

 

That should be correct, but I'm not gonna place any bets on it.... :-)

 

The rear tone ring may have a different number of teeth on it since it's a larger diameter. It will probably work right, but the TCM or ABS module may need adjustment for the computers to read them right (i can't remember where the wheel speed sensor data is stored on a 97). If the number of teeth are the same, then the larger ring would have bigger gaps between the teeth or bigger teeth which could also give a reading. So I am not sure how Ford compensated for this between the trucks.

The double cardan joint compensates for extreme driveshaft angles. Some years Ford used them, some they didn't. It reduces the possibility of vibration but may not necessarily be because of the short wheel base, but probably is.

 

my extended cab fit just fine and the sensor still works

 

yeah sure enough my drive shaft is just an inch longer, an i have the double u joint as well. but with the 2 inch block in it right now the yoke is slid out about a 1/2 inch so i may be ok with the skyjacker 5 inch rear lift springs on top of that. that will be goin in along with the rest of the lift shortly before the axle goes in an the front gears. cant wait till its all in. then time for some 37 13.50 m/t's. Then i should have a direct bolt together set up hopefully my abs sensor is the same as yours or atleast reads as it should.