I recently purchased a 1948 Canadian F68 (same as a F3 I think). It has the 122 inch wheel base. A previous owner replaced the 8 lug nut wheels with 5 lug nut wheels. It appears to have the 4 speed transmission. I understand it is not synchronized. I want to keep it fairy original and would like to use the 3 speed transmission from a F1. Can I do that and would I have to replace the 2 piece drive shaft I now have?

 

The F-1 truck has a different tranny cross member than the F-2/3 models which then necessitated a different rear bearing retainer F-1 vs F-2/3. The rear bearing retainer doubles as the rear mount. I'm not sure whether the spur 4 speed piece would mount to the half ton 3 speed unit. Maybe one of the other guys knows. The path I will take on my next project is to substitute a T-87 heavy duty 3 speed for the 4 spur. The 3HD is synchro on 2nd and 3rd, and is a bolt in swap because it was an OEM option on F-2/3s. There was a 3HD tranny on eBay last week, but I don't know whether or what it sold for.

Btw, welcome to the forum. Stu

 

Welcome to the forum. We like pictures. It sounds like your truck has already had an obvious significant modification so is no longer original. That said, I would consider the benefits of an OD transmission if I were going to the trouble of changing to a different transmission. Again, welcome.

 

Thanks to you both. I think I will try the HD 3 speed.

It appears to also have Dana 44 rear ("44" stamp on back of diff). Can I replace the ring and pinion with a ~3.5 ratio? I turned the diff and it appears to have a 4.1

 

Note that the HD 3-sp has to be out of an F-3; one from an F-1 or F-2 will not have the correct rear bearing retainer.

The Dana 44 was not the stock axle in your truck. Is there a small metal tag under one of the bolts on the rear cover? If so, it will have the tooth counts (for instance 47 / 12 = 3.92) It could be a '51 - '52 F-1 axle, with either a 3.92 or 4.27 ratio. There are many threads on here about using a Ford 9", Dana 60, Explorer axles, etc. in place of the stock axle. Most are about changing an F-1, but the key points are the same. I'd suggest doing a Google search, it will pop up lots of articles on here, for instance:

1948 through 1960 Ford F-1 and F-100 Rear Axle (differential) Swaps | Ford Trucks

https://www.ford-trucks.com/forums/9...r-54-f100.html

 

I don't think that's correct, Ross. The F-2 and F-3 tranny cross members are the same. The only issue that I see is that the 3HD's 8D 7085-A has no hand brake drum provision as would apply 48 to early 51, and 8D 7085-B has the arm for the brake drum in late 51 and 52. The 4 spur has a different retainer 8D 7085-C. Stu

 

I guess that's right, Stu, I was thinking the F-3's were the smallest trucks with the big hoop crossmember, looks like F-2's also had it. You're right about the drum-style handbrake, but if he has a D44 rear axle, perhaps the PO added the hand lever under the dash? Good pics here:

https://www.ford-trucks.com/forums/1...l#post10483850

 

Thanks again. I am so glad I joined this forum.

My truck has a hand brake and the cables that run to the rear drums. There is no tag on the diff.

It seams I should keep everything except the 4 speed and do the 3 speed HD.

 

Light duty 3 speeds with the rear mount to fit a big hoop cross member do exist, they are just very rare. I found one a while back, documented in this thread (it may still be available, PM me if you want a phone number to try):https://www.ford-trucks.com/forums/1...ybe-f-6-a.html

 

Dana 41's were stock for 1948. Sometime around mid 1950 the Dana 44 came available. I have 1 of each, and when disassembled, the innards looked different than a modern Dana 44. IE: different spline counts for everything; different slingers, different bearings, different differentials, spider gears, etc... That said, I have a Dana 44 from a Jeep ZJ, but by the time I made it fit, I could have swapped in several Ford 9" rears from 57-72 F100's. But since yours is an F68, swapping back to 8 lugs would make it look stock to those who know these trucks. But for the other 95%, a '57-72 9" would look stock, with the 5x5.5 lug pattern. Then from there, your gear ratios aare endless as well as brake options.

Transmission-wise, as others have said the HD3sp would be the best fit. One possibility is to use the F1 crossmember with the LD3sp. Dimensionally, they do interchange somewhat, but the rivet holes don't line up at all.

 

I am somewhat lost with this thread. I am going to the Charlotte auto fair next weekend and hope to get a synchronized trans for my 1948 truck. Should I just look for a 3 speed HD trans?

 

In my opinion, yes. But make sure it has the tailhousing on the tranny with the short flat bottom below the tranny. The F1's are in a line with the tailshaft. Here's a lousy pic of a 4sp for the F2. The rear housing/mount would be similar to the F2's HD3sp.

Second pic is the F1 mount. Third pic is the F1 3sp with the half round mount still attached. You'll notice there's quite a difference between the F2 pic and the others for mounting. Last two pics are the F2 crossmember and the F1 crossmember.

 

Here are the pictures of my F2's heavy duty 3-speed with the transmission drum brake attached. It also shows the part number in picture #4 if that helps you locate a unit at the swap meet. Not sure you can easily remove the drum brake components and use the transmission without it. The drive shaft length probably won't match.

Tom

 

Thanks so much. Should I also look for a T87D as stamped on the case?

 

The numbers are cast into the case, but the cases use the same number for several different styles. You want a T87D, but with the deeper rear support as shown. The arm off to the side may not be on it, that is for a drum e-brake brake mounted on the output shaft.

Note -- edited per 52Merc's later post