So i should start off and mention that i am new to this forum and Ford trucks all together. My name is Joey and I am used to Honda, Acura but I just bought this Highboy a few months ago and am now getting around to doing little tweaks and such.

The truck is a 1976 F250 390 4x4 and it seems to be in pretty good shape aside from the fact that the guy who owned it before me really did a number on the wiring and so far i have had to go through and redo all his work. Which he apparently did the head gaskets on it so that means I'm going to have to pull the heads anyways that's besides the point.

Last weekend i was just doing a regular look over (me standing over the engine bay dreaming of what i can do) and i figured i would try out the 4 wheel drive. I then proceeded to shift between 4H and 4L and back to 2 which was very difficult to do, I had to sit and rock back and forth to get it out of 4L I'm assuming that's pretty normal for an old truck, maybe not?

After that with it in 4L and in my granny first driving forward I noticed the back tires were spinning and the front tires weren't. So in my mind I must have mismatched gears in my axles. My question is how can I tell what is in there, or what gears are stock for these trucks?

I have never worked on gears before so I apologize if its an obvious question but like I said I am new to the truck universe. I also figured I would post since I've been a member for a while and haven't done that yet. I do plan on taking the motor out and eventually rebuild it, also do a resto on the body but all that in good time cause it runs ok for the time being. I am happy to be apart of the Ford family!



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Did you check to see if front hubs were locked in?

 

yeah they were locked i made sure of that haha

 

Hello and welcome to FTE. There is a ton of info here along with many who are excellent at helping, provided you are able to describe your problems. This is just a general statement and in no way am I trying to pick you apart. Sounds like (and looks like) you got yourself a decent truck. Pic looks good from my house!! LOL. Wiring issues can be a pain, and unfortuneatly sometimes the hardest to diagnose on the forums, but like I said earlier it all depends on how well you describe it. If you have a basic understanding of electrical stuff, then you got half the problem solved. A voltmeter/multimeter is a must in my opinion.

Yes, it can be a real PITA to shift the transfer case between all the ranges 4L, 4H etc....so what I did was just sit in the driveway, engine off and shift it back and forth thru all the ranges. That seemed to smooth things out for me. Mine gets stuck in 4L sometimes too so its normal.

Post up your VIN tag off the door if you want to know all the specs for you truck which will tell what gears your truck "should" have. The ratios should match or be real close. 3:73 or 4:10 is the most common.

 

Are you fearful they're on backwards?

Drive in reverse 10-12 feet, t-case should now shift gears (this is normal).

Put the t-case in 2wd, lock the hubs in, using a long screwdriver try to turn the axle shaft u-joint behind the knuckle (they shouldn't turn), all it takes is one hub to not engage and you have no 4wd.

Stock is 4.09/front 4.10/rear

 

I just don't trust his work from all the other work i have had to redo. I just feel for my own piece of mind i want to do it myself.



I suppose I should clarify it was in 4L but the tires were spinning at different speeds, the front tires were spinning at like half the speed compared to the back

 

Might be time to pull diff covers and count teeth, or look for a ratio stamping, who knows what a PO may have swapped in.

 

. Welcome to here.....

Do one axle at a time with the transfer case in neutral. Jack the truck up just enough to get the tires off the ground, put a mark on the backside of the tire, now turn the driveline and count how many rotations it takes you to turn the tire one time. That should get you close enough to know.

Use all the correct safety precautions when working under a lifted vehicle.

 

Some of these trucks were equipped with a full time transfer case. I did not see in your OP if it was a full time 4x4 or part time 4x4 that was converted to hubs. If it has a part time 4x4 you might be in need of a matched set of ratios in your diffs, if it has the full time 4x4 these trucks were supposed to have a differential built into the transfer case, if this is what you have then I suppose that the front could spin faster or slower or the same speed as the rear. You will need to verify your transfer case equipment and go from there, there might be no problem at all.

 

I believe it is a part time t-case with converted hubs, I will have to keep you posted, im hoping the rain stops so i can go do some checking

 

Your shift pattern looks like so, correct?

NP205 (part-time)

 

Yes sir my **** doesn't look that nice but yes

 

I love the look of those ****, wish the 4sp shifter had the same pattern design.
Sorry for off topic, would do what AK Ford Guy said, would give you a better idea of whats going on. Or pull the covers should have the ratio stamped on the ring gear. Wouldn't be a bad idea to change your fluids and inspect everything.