Hi, all - I am seriously contemplating swapping a '57/'72 F-250 rear end under my '51 F2. I've already talked with Irondragon (Jon) about it, but looking for a few opinions. The reason I would be doing it, is to go faster than 45 mph. Also, internal parts other than bearings are pretty much non-existent on the stock rear. I know that the '57/'72 will bolt right in, with "possibly" a need to change the driveshaft a bit.

My concern is, the tranny is a spur gear, with granny low. That means I would be starting out in 2nd gear.

Now, with a higher gear ratio, would I still be able to start out in 2nd? Has anybody done this, with a truck that's on the road? What gearing did you end up with, and how does it do, starting out in 2nd?

Another question would be the parking brake - do I just leave it disconnected? Mine has the brake drum behind the tranny.

Also, while I'm at it, does anyone have an "extra" Dana 60 from the above year F-250's? I will be going to school in Oklahoma from Indiana, in October, so someplace along the way, or even a bit out of the way, would be great! I've gone to Kansas on the way out before, to pick stuff up. Also, Ohio, Illinois, Wisconsin, Michigan wouldn't be out of the question, as well as northern Texas.

Thanks, in advance!!

R

Page Eight in the never ending saga is up! Here's the link:

Page Eight - Roger's '51 rebuild

 

I can't say about yer trans, Roger, but in my '78 F150 with NP435 (granny low) 3.50 rear gears, 36" tires, I'd still be able to roll out in 2nd gear, though the 351M has low end torque. With the big tires, I should have 4.11's, but I don't, therefore my overall rpm at 65mph is rather nice. (IE low) So converting that to your truck, starting out in 2nd gear with a 4.11 gear ratio, which is typical of any Dana 60 found in the JY, I don't see any problems. That said someone who has done it would probably have a better answer. Oh, and I measured the Dana 60 in my '73 IH 3/4 ton and it has 61" trackwidth. And a 34" wide frame, so the pads might be right on. Huge brakes on this beast, lol. I'd use the trans P. brake drum if it were me.

 

I'lll have to take some measures.

I am going to keep the trans brake - I was talking about disconnecting the rear parking brake, on the new rear. I assume they are cable to rear?

Thanks,

R

 

As for the park brake. If you are not using the park brake at the drums I would disconnect the cables inside and remove them. It will have no effect on the service brakes and there is no use having the cables hanging underneath.

 

I've done the axle swap on my 52 F3 with an axle from a 71 3/4 ton that has 3.73 gears. I always start in 2nd gear and have no problems. I also took the parking brake cable out all together. The only problem I ran into was the u bolts I ordered didn't fit. They weren't long enough. Of course I didn't notice it until everything was apart and being that my truck is my daily driver I had to get it back on the road asap so I called around town and found a guy who made them for me. Anyway, good luck.

 

Great! that's what I was looking for...

Now, the $64,000 question - what kind of speeds are you getting on the highway, with the 3.73?

Thanks,

Roger

 

I'm doing about 45 - 50 and the rpm's are not too high. I could go faster but I don't want to push the engine in my truck. I guess I baby it. I wish I could tell you exact rpm's but I don't have a tach. I hope that helped or even made sense.

 

Any of you guys know the trackwidth of your rear ends? If the IH one I have works, I may keep them for a possible 4x4 conversion down the road.

 

That's about my style, also - I don't care so much about going over 50, I just don't want to be screaming and howling, every time I do!

Thanks for the info! Now, to find a rear end...

R

 

What gears are you planning on using? Let us know how it comes out.

 

This may sound stupid but, what do you mean by trackwidth? Let me know what measurements you need and I'll get them off my truck for you.

 

I have just begun to research what gears would be available. Hopefully, I'll find between a '70 and '72, but might have to use what I can find. I'd prefer not using the 4.11, which I understand is one that's available. Seems like when I WASN'T looking, the F-250 rear ends were all over the place...now that I AM looking, can't seem to find one! It'll show up, sooner or later, or I'll have to use mine for now. I just don't want to spend the money for the brakes, if I'm just going to replace the rear end.

I'll keep you posted...

R

 

Roger, I used a dana 60 3.73 out of a 69 and it was truly a bolt in swap. I removed the parking brake cables and hardware from the new rearend and still use the band brake on the rear of the trans. It has made driving 50-55 much nicer, engine rpm's down along with engine noise etc.

 

Dana 60: The ID tag which tells what ratio it has, is under one of the bolts that holds the inspection cover on. By now...it's usually missing.

On 1973's and later, the tag is bolted to the housing to the left of the inspection cover.

From 1967 thru 1972, besides the 3.73's; 4.10's & 4.56's, 3.54's were also available.

Out here, these pre 1973 Dana 60's are fairly EZ to find. The only problem is...out here is SoCal.

 

Thanks, sgtrwg and Bill - yeah, out there in Collie-phornia, there's lot's of older vehicles. Just a little far to try to ship a rear-end. And I hope it's as "bolt-in" as your '53. Never had to deal with changing spring perches, and the like.

I think the 3.73 would probably do me perfect - I would worry a little bit starting out in 2nd, with any higher gearing, as the 3.54. And, from what I remember, starting out in first for normal driving, wasn't really an option, even at 3.54 I wouldn't think.

Calling junkyards today...

Thanks again,

R