Looking for some help, I put a 71 351C with a 93 5spd and 93 10 bolt posi rear diff in a 79 F 250 Supercab. That was all fairly simple but I can't figure out how to get the speedo to work. Anyone out there done anything similar.

 

Which 5-speed?

What is a 10 bolt? That typicall GM speak for a Chevy rear axle or a BOP axle. Do you mean an 8.8?

.. there seems to be a bad trend of vagueness in FTE lately. Help us out by being specific and the specs on the truck yer working on... one way is to put the specs in your signature.

 

The way I read it he put the 5spd tranny and rear end out of a 93 ford truck.

Depending on which rear end he has both the 7.5 and the 8.8 have 10 bolts.

Here is the 7.5 rear


Here is the 8.8 rear


I'd say you have a speedometer gear incompatibility. You *may* be able to correct the issue by changing the speedometer gear in the tranny. You need to figure out which rear gear set up you have and then figure out which speedo gear you need to make the adjustments. There are instructions on the net that should get you fairly close if not spot on.

Hope this helps.

 

Doc G got it. Sorry if I am not to technical, and forgetful, when you do these things in your spare time everything takes twice as long. Just went down the the shop and relized that it is a 12 bolt [ had to count twice ]. The 5 spd is a std. don't know if Ford made more than one in 93. It is out of a F250 same as the tranny. My problem is the 93 speedo is electronic with a pickup I believe on the rear dif. and the 79 is mechanical.

 

Guessing a ZF trans if F250, not sure iif they had a mechanical speedometer drive in the tail shaft. When I did the M5OD swap in my 78' I had to swap tail shafts with one that had a spot for a mechanical Speedometer pickup.

 

actually the tailstock is on the transfer case, there is a dent in the tailstock but no hole in it. Any ideas where I could get one. Thanks Mel

 

92-97 HD trucks use an electronic speedo sender from the axle, AFAIK there in NO way to drive a mechanical speedo off a tranny from this era. But since the axle was swapped too, a servo setup could use the signal to drive the mech. speedo, but that will cost a few $$$.
Axle should be a Ford Sterling 10.25 whether semi- or full-floating. Just about as indestructible an axle as any out there.

 

Could the '79 transfer case bolt onto the newer aluminum transmission? then use the t-case to drive the speedo... If the t-case doesn't have a spot, I'm sure a trip to the junkyard will help find one that has the hole drilled. Then either tear both apart, or simply use the junkyard piece.

I read through this thread and not quiet 'seeing' it to get it though mah thick head