HI, This winter I put in a rear end from a 1967 F-250 into my 1955 F-250 to replace the split rear end that was stock. I was told that it was a bolt in thing here on the board and it was. Tonight I went to slide in the orig drive shaft and it seems to be about 1-1.5 inches too long. It is a 2 piece drive shaft with the carrieer bearing and I have the 2 halves slid together tight, and there should be some play for suspension travel.

What I want to know after the hour of swearing and trying to make it fit does the drive shaft have to be cut down in order for this swap to work??

My guess is that the front of the axle must be forward an inch or two more than the org, which is 200 miles away on my dad's firewood trailer otherwise i'd just check that. any one have any ideas on this?

 

Hardly ever will the original drive shaft length work with a rear end change...even a bolt-in and often the yoke requirements are different. You will have to have the shaft shortened to make it fit. I usually shorten my own driveshafts. It's not too hard. I cut the rearmost yoke off the tube using a hacksaw, shorten the tube the necessary amount, and then re-weld the yoke on the end. Just be careful that the cuts are straight and the yoke is phased when you weld it back. I wrap a piece of light cardboard around the shaft and cut right along the cardboard edge. I've done many and never have had a problem with them. My current project uses a GM transmission and a Chrysler rear. The 87 Chrysler driveshaft length was perfect but I had to remove the Chrysler front yoke and replace it with GM yoke...

Vern

 

I cut mine like that .by phased I think he is talking about putting it back in the same position as the yoke on the other end like it is now. the way I done mine was I put a straight line down the drive shaft a little longer than what I was cutting out (with a marker) and just joined it back with lines meeting.cutting=I cut right next to the factory weld with a hack saw only going as deep as the thickness of the tube so not to cut into the yoke then I cleaned it up a bit with a grinder and then cut off what I needed off the shaft with the saw. stuck the yoke back inside the tube and it was a tight fit so all I had to do was lay the shaft in a v shaped place and turn slowly while a friend welded it.for free I might add and it looks better than the factory weld on the other end. doesnt vibrate either. If a inch or two is all you need maybe you could just cut that much off your splined piece that comes out of your carrier bearing and maybe a little off the yoke that goes on it,just dont cut too much off. this is only my opinion though cut as you please.

 

Did the same thing with my 53 f-250. It ended up with about 1" of play rather than the 2.5" that it had with the original rear end. I had a heck of a time getting it to go on, finaly figured out that there was a lot of old grease built up in the yoke. Cleaned that out and it seems to work now. I suspect that unless I put a realy heavy load on the inch will be enough, I don't think that there is alot of vertical movement in the axel alone if the truck is empty.

I've put a couple hundred miles on the truck since the swap and have not noticed any problem. The next project is to swap the original trans for an S-10 T-5 then I'll have to work on the drive shaft length.

Have a great day....

Bob G

 

I'm glad to see there are other old school shadetree driveshaft makers here. All to often the first thing you hear is take it a driveline shop and let them do it. Sure you can do that and pay $75-$100 or more for something you can do right in your own garage. Once in a while you might screw one up or need balancing. Save the trip to the driveline shop for then. Low Budget gave a better description of the process than I did. Thanks.

Vern

 

Well thanks for the advice I'll look into it a little more before I go and start cutting up the drive shaft. But my Dad said it pretty good " you wont be out anything to give it a shot." For you guys that did it your self, If it needed to be balanced were you able to take it somewhere to get it balanced or did it work good the first try?

-Scott

 

Scott,

I've done about 10 or so over the years and never had to have one balanced. I took one to a shop that I thought was out, but the vibration I was having turned out to be a bushing in the rear of the transmission. If there are any balancing weights tacked to the shaft avoid cutting them off if possible. Sometimes you can shorten the shaft from the opposite end to avoid cutting off a balancing weight. Yes, a driveline shop can balance it with no problem. The main thing is to be sure you weld the yoke back on straight. If not, it will wobble and the only way that can be fixed is to cut it back off and re-weld it...

Vern