4 SPEED TRANSMISSION-Pickups

[35ragtop]

Hi All,
is there any literature or website info on the 4 speed transmissions used in light trucks? The only information that I have found tells me that the 4 speed used in the 1/2 tonner is different to other bigger trucks but no specifics on what parts to use to rebuild.
Any ideas would be welcome, thanks
Dave h

[Bob C]

The spur gear 4-speed trans was basically the same from introduction
in late 1929 to the early 50's.

Bob

[alanwoodieman]

4 sp trans in a pick-up has a different universal joint to fit a smaller torgue tube driveshaft, open drive line trucks used a different mounting arrangement on rear of trans and had a different universal arrangement (case is still the same) 47 had a two piece trans case, 6 cylinder used a different case to adapt to the 6 engine, same with a 4 cylinder (41/42)

[rheltzel]

To install a 4sp 1 1/2 Ton transmission in a pickup, you will need the universal joint mentioned above (81C-7090) plus the special spacer for the radius rod ball (81C-3442) and the longer bolts to install the cap with the spacer in place (22247-S, front radius rod bolt, 7/16" -20 x 1 1/2). These latter parts are necessary to allow the larger transmission case to fit between the wishbones.

The 4sp didn't become an option in pickups until '38, but will fit in earlier chassis; I had one in my '37 pickup.

Think twice before you go to the trouble of converting to one, however...the 4sp is essentially a three speed with the addition of an outrageously low first and reverse, which are of limited use unless you do a lot of heavy hauling and/or off-roading. Except in those conditions, you always start in second gear. Thus, second and third perform the same function as first and second on a three speed.

With its straight cut gears, the 4sp is noisy and must be double-clutched to shift without crunching the gears. They're pretty rough/uncivilized compared to the three speed.

On the positive side, they're absolutely indestructible and if you enjoy double-clutching, are engaging transmissions...they have an unmistakable sound that some people (me for one) love.

[49fordv8f4]

I'm not sure what year you are needing info on. The open driveline trucks used the same 4-speed for 1/2 thru 1 ton. The transmission is basically the same as the 1 1/2 and 2 ton 4-speed with the following exceptions; the smaller trucks use a different rear mount, tailshaft, speedometer gear, and driveshaft yoke. There is also no parking brake assembly on the smaller truck transmissions, although all the cases have the provisions for the parking brake linkage. Everything else from the rear of the transmission case forward, with the exception of the tailshaft is the same for all T9 4-speed spur gear transmissions. The case was changed to a two piece case, IE removable half bell/hogshead, in '41 or '42. The later case was used for replacement service on transmissions back to '32. Any T9 spur gear transmission up to '52 can be adapted to trucks back to '32 with the proper tailshaft, rear mount, and driveline parts.
I hope this all makes sense, Mark Poley

[35ragtop]

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Thanks for your replies so far. The 4 speed is in a 1939 1/2 ton pickup ( not running) that I am looking at buying. I was just wondering about the pros and cons of doing that up or changing to a 3 speed. I have plenty of info on rebuilding 3 speeds and have done a couple, but know nothing about the 4 speed or have any technical data on them. I just thought that the 4 speed in the 1/2 tonner was different to the 1 1/2 tonner units., but apparently not too different.
Is there any technical data out there (part numbers etc) on these 4 speed units.
Dave

[rheltzel]

The "Green Bible" ('28-'48 Chassis Parts and Accessories Book) has the parts numbers along with great illustrations showing all major components of both cars and trucks. You might check with VanPelt (http://vanpeltsales.com) for more information on the transmissions.

Before you decide, drive a truck with the 4spd to see if you like it. Might save you work and grief.

[alanwoodieman]

I had a 1/2 ton with a four speed, noisey but neet to drive. I have a 1/2 ton, 3/4 ton's with 3 spd-easier to drive, better gear ratio's, the 3/4 ton has a car trans-higher first gear, better speed in second with running a 3:50 rear gears or even a 3:25. I have a 1 1/2 ton with the 4spd and I love the whine of the gears, just seems to go with the truck. 4th gear is a direct so no noise.

[35ragtop]

Thanks for your responses, I will do more research. Im favouring a 3 speed at present, don't mind double clutching as I have the 35 and the 34 pickup, so normal V8 ing for me.
Dave

[COE Dan]

There is a small (5in x 8in, black cover) book titled “Repair Manual Transmissions, Clutches, Overdrives and Power Take-Offs” with a pamphlet number of 3697-47 and covers 1932-1947 transmissions to include both the 3- and 4-speed. There are originals frequently on ebay and there are repros out there also available from some of the V-8 parts suppliers. I think Van Pelt Sales mentioned in a previous post has copies available. This manual gives you Servicing, Overhaul, and Disassembly/Assembly instructions with some pictures. I don’t recall offhand if there are specifications provided (i.e. gear ratios, part numbers, tolerances, etc.).

I’ve got the 4-speed in my ’47 COE and the 3-speed in my ’39. I don’t mind the double clutching and once you get the hang of it, it becomes second nature. It’s really not any slower to shift than the 3-speed if you have practice. It will be noisier however.

[johnh7]

I had the 4 speed transmission with the compound low first gear in my 38 1/2 ton. It really whined going down the road and first gear was only good for about 7 miles per hour. I replaced it with a three speed that is much quieter and shifts easier.

I am now looking for a transmission with better gearing so I can drive it at freeway speeds. I found this site: http://www.modelaonly.net which sells a four speed with overdrive built in for the model A and another transmission for 35 - 39 Cars. I don't know the gearing. I have written and asked for it, but I have not yet received it. Is anyone else familiar with this product?

[oldandtired]

I have a 39 half ton panel that cdame with the 4-speed. When I pulled the engine and trans, the rear trans brace on the fram was fractured and missing a piece. I ended up replacing the rear trans mount and putting in a 3-speed. The 4-speed is still sitting on the shop floor over in a corner. I have moved it a few times and it takes me some doing. The 4 speed is really heavy compared to the 3-speed.