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Is there a later bolt in 4 speed with synchromesh?

What OD transmissions that are bolt in?

Having to have a new driveshaft made is acceptable.

Anything else that I need to know?

What year and model truck?

How did I forget that.

1946 2 ton, 160" wb, 4sp trans, 2 spd rear.

I'm not real familiar with the older (than 48) trucks.
Does yours have a bracket on the transmission for the brake and clutch pedals?

To use most any later or different transmission I expect you'll need a 48-53 bellhousing which will have a more useful bolt pattern, still fits your stock mounts, yet won't have provisions for brake and clutch pedal. This thread and pictures linked in it is one option for replacing the brake and clutch on the new bellhousing. https://www.stovebolt.com/ubbthread...in=157950&Number=1109074#Post1109074

After you have that sorted out you have a few options.

Later model 4 speed with syncromesh is the SM420 (found in 1948-67 trucks), and it bolts in to the later bellhousing, no adapters or anything confusing at all. This is still a direct drive transmission, will go just as slow as you already do.

Some chance you can find (and fit) an old Clark overdrive 5 speed from something like a GMC 400 series. they were made with the standard GM bolt pattern, but not all of them. The overdirve models will have a VO after the model number, for example 205VO. The "O" indicates overdrive. I'm not sure what troubles you may run into but possibly the input shaft is a little extra long, requires a spacer or machine work to input shaft. Will likely need a different clutch disc with larger splines. Might need 5-1/8" bore in bellhousing or take care of that with the spacer/adapter or machine work to bearing retainer or bellhousing. I have not done this swap, but I am sure one way or another it can be done.
Downside is finding the transmission and finding one that is any good, they're now quite old and parts are scarce.

A more modern but not quite cheap option is an NV4500 5 speed overdrive. This requires a spacer/adapter like so http://www.advanceadapters.com/prod...ansmission-to-a-gm-v8-adapter-plate-kit/
Also need to enlarge the bore in bellhousing from 4-11/16" to 5-1/8", or ask if they have a more suitable adapter already made to suit.

Another 5 speed is the T5 from an S-10 pickup. It is a pretty easy swap but not really suitable for a full size truck. I'd save that option for the 1/2 ton guys.

Next you could use a separate auxiliary transmission like the Spicer 5831 for example. This takes more fabrication, adds another shifter, more weight, and some complexity when shifting the unsynchronized second transmission. Also takes some effort and or money to find one.

There are also overdrive boxes you can bolt between engine and transmission like this "Ranger torque splitter", I've heard good things about them.
http://www.advanceadapters.com/prod...overdrive-27-with-a-4686-retainer-index/

Then you have bolt on overdrives behind the transmission, very expensive.
https://www.gearvendors.com/cg2wdt.html

US Gear had a similar product, now out of production.


I'm sure there are other options but that covers many of them.

Grigg

I do not know if there is a brake clutch bracket on the transmission. I'll have to look.

It would appear that for me the easiest way would be to find a 48 -67 trans and a 48 - 53 bell housing then add a gear vendors OD and have a driveshaft made.

Besides getting and adapter from Advance Adapters can I still use my original clutch housing even if I have to have the center hole machined larger. What else is involved?

What is involved to do a T5 S 10 swap?

I doubt that is the easiest way. The Gear Vendors unit is also very expensive, not at all a good value in my opinion. A quick look on the site shows they fit various versions of the SM465 which is a 4 speed that replaced the SM420 on about 1968. They may or may not have off the shelf parts to bolt one to an SM420, and you'd probably need a 4x4 version to start with. Or make some more changes (like bellhousing bore) and fit an SM465.
All it takes is time, money, and some effort.

If you've considered the Gear Vendors then for half the money and much less trouble to install you can get the Ranger Torque Spliter that will easily work with most any SM420. You'd need to make a new shifter hole in floor/transmission cover further back, and a second one for the Ranger. Shorten driveshaft.


I don't understand what your question about the adapter from Advance and clutch housing bore are related to or about?

For the T-5 swap you can search a little on the forum. It's not really suited for the larger trucks like you have and I would not recommend it for one. I was only mentioning it to exclude it because in your research you will surly come across them as yet another a 5 speed OD option.

If you are looking to replace the non-synchronized transmission for the synchronized SM420/465, there is an altered late bellhousing (1948-62)that grafts the clutch/brake brackets from a truck like yours (1937-1947). Don't recall who sells the modified bellhousing, but a little Google searching would get you to it.

Or I already provided a link to thread with a home made steel bracket and dimensions for to do the same.

Be aware that if you gear up very much the engine might not be up to the task, torque-wise. There's a reason the truck has a slow/slower option with that 2 speed rear. The old 216's and splasher 235's didn't have a great deal of torque, and raising the gear ratio will have you downshifting so often you'll feel like you're rowing it with the shift lever. The SM-420 with a Brownie auxiliary trans might be the best option, which will give you a selection of under/direct/overdrive ratios for every gear in the main box. It turns your 4 speed into a 12 speed overdrive setup. On the rare occasion you'll be able to get into top gear, you'll have good road speed. Don't forget to do a major upgrade of the brakes and do a total overhaul of the steering- - - -getting it up to speed is only half the job, and keeping it between the ditches and getting stopped from higher speeds can get exciting.
Jerry

To jump on Jerry's band wagon about being torque-limited ...

I have a splasher 235 (the big brother to your splasher 216) in my 1-ton pickup. I upgraded the rear axle to a better ratio for higher cruising speeds. In short, I have a lighter truck and a bigger engine than you. But Jerry is 100 percent correct that with aux boxes, rear axle tradeouts, taller gears, etc, you are going to run out of power fast. My truck will cruise at 60-65 all day.... until it hits a hill ... or a traffic light .... and then it takes awhile to get back there. At the top end with a splasher engine, you will just not have any power.


My pickup with a splasher 235 and 4:10 rear axle, from a dead stop, takes just over three miles to get up to 60 mph. Just sayin'

I would love to be able to do 60 on a level highway. Happy with 55. Still happy with 50.

Back in the 70's I was a volunteer fireman. My engine company had a 1948 White. Straight 6. It had the smaller engine, I think with a 4 speed. There were trucks from the mid 50's to 70's.

It was the only non governed truck in the department. It would hit 68 on the interstate though it took a long time to get their.

Well, that's *my* truck.... I have no idea how your truck (heavier truck, smaller displacement engine) is going to do it.

One other thing they've told you above that's very true -- on my truck, even though the truck will now hit 70, it's not very fun. I need to redo the king pins and the tie rod ends because the steering becomes very active above 67 MPH. And my truck is a low-mileage, garage kept survivor.

At highway speeds, a underpowered bigger truck with an unrestored steering, axle and suspension is probably going to be dangerous...

I think the bottom line that we're trying to tell you is that just putting taller gears in your truck isn't going to do for you what you hope it will.

All good points.
Just a .75 OD ratio will only gain about 15 mph, not going to be real speedy even if it had plenty of power. And otherwise with the first 4 gears will drive just as it does know. The OD would be handy on moderate down hill and level, but if it struggled to pull any given hill in high gear now there's no way you could do it in OD either.

Calculate speed here http://www.onlineconversion.com/bigger_tires.htm

This is the first week that we have the truck on the road. We have only stayed on the local roads close to the house.

One of the first things we found out is that the speedometer does not work. I disconnected the speedometer cable and found the housing had no cable in it. So a new cable and housing have been ordered.

I do not remember the source but it said that the 1946 2 ton with the governor has a top speed of 48 mph. That the governor reduced top RPM 200. Though someone had already taken the throttle plate out of the governor.

Until I get the speedometer straightened out. Or a get a GPS will I know how fast this truck will go.

So how much more speed will 200 more RPM's get me?

I do not want to make this a 70 MPH truck. And if I did the resources are not there to get it.

And, I have been around enough old autos to know that they will not hold their speed up a steep grade.

Though if an OD could get another 15 MPH that would take me to a top speed of 63. Though my son would be happy if he could do 50 - 55 with the pedal still off of the floorboards.

My son has no plans to mod this truck so it is going to stay stock for the time being.

My 46 2 ton has a 0.85 overdrive ratio in the auxiliary. I can cruise at 55, but a hill will bring it down fairly easily, and even on level ground there isn't much throttle left. It is capable of more than 55, but brakes and steering start getting interesting after 55, so I stay below it. The engine is pretty well wound out at 55 anyhow.

Is the governor still on your truck?

If it was still on when you bought the truck was the truck running well enough to give a comparison of with the governor and without?

The governor is still on my truck, but was supposedly adjusted to not have an effect sometime in the 50's by my grandfather. The truck has been in the family since new. It still has the throttle plate, but as best I can tell its not doing much. I have a vacuum gage plumbed in to the manifold and is between the engine and the governor / carburetor. The gage would indicate if either the carb throttle plate or the governor throttle plate was / is closing. I have not noticed the vacuum reading changing out of sync with my foot throttle input. If the governor was limiting the engine speed by throttling, there would be an increase in vacuum while this occurs and would appear on the gage as if you were lightly lifting your foot, but without your movement of course. If I floor it while at 55 mph or any speed, the vacuum will drop to something less than 2" hg, the lowest reading on the gage, and stay there until I lift my foot. To give an indication of how hard the engine is working to maintain 55 mph, I'm someplace around 6" hg just to maintain speed. Dropping down to 45 brings it up to around 13" hg. For reference, my engine idles at 19" hg.

My splash oiled 235 has been gone through and is in about the best mechanical shape one can be in at the moment. It has plenty of pep, and while rolling in 2nd direct, a blip of the throttle can break the duals loose if nothing is on the bed. The engine makes decent torque, but loses it quickly high in its rpm range. It will maintain 45 mph on the few small "hills" that are nearby with anything under 4500 lbs in the bed, it will not maintain 55 on these hills with or even without a load. No load on the same hill as above starts out at 55, but is down to a hair under 50 by the top, and would probably lose more if the hill was taller. I have had occasion to drive my truck around the texas hill country, up near Crenwelge's neck of the woods, and those hills are actually hills and even empty I struggled to break 45 on the steeper ones.

Accelerating the load is another story, it takes miles to get wound up when heavy, although once you get it there it holds fairly well on moderately flat ground.

A post filled with lots of good detail. Thanks.

I have a 1965 Chevrolet c-20 4 speed manual transmission. So. My shifter comes from the floorboard, however I have a SECOND shifter coming from the floor board that has 3 positions. The middle position seems to be neutral where the truck won’t move at all and so I don’t know what the forward or back position does for my shifting with the longer shifter? I don’t even know what this second shorter shifter is called or what it is so someone please help me?

Mocha

Look up “ranger overdrive” and see if that looks like what you have.

Also “Watson overdrive”.

Any tags on the transmission?

Is it 4x4?

Also Spicer, Brown Lipe aux. transmissions. Underdrive is left and back, direct is right and back, OD is right and fwd. all shifting goes through neutral in the middle as you mention. Not synchronized, need to match engine RPM to road speed before shifting(easy after a short learning period, learn how to properly use clutch.)

Ed

If your truck is not a 4 wheel drive, then most auxiliary transmissions will split the gear ratios in your main transmission. If you place the main transmission in low, you can start off in each of the gears available in your auxiliary to get a feel for what it does. If it is a two speed as you have indicated, (3 positions, one being a neutral) your shift pattern could be something like 1L 1H 2L 2H 3L 3H 4L 4H. with the L meaning low gear in the aux box and the H meaning high gear in the aux box. This also would mean every other shift you would be moving two levers at the same time. Keep in mind that it is ok to skip gears based on your load and speed so you definitely don't have to use every combination every time you start from a stop. It is also possible that the aux box you have acts like a low range and is not normally used in highway driving much like the low range found in many 4x4 boxes. One way to tell would be if the gear ratios are relatively close together or are far apart in the aux box.

As an example, my truck has a 4 speed and a 3 speed auxiliary. The auxiliary provides a slight under drive (U), a direct drive (D) and and a slight over drive (O) to each gear of the main 4 speed transmission. My shift pattern is 1U 1D 1O 2U 2D 2O 3U 3D 3O 4U 4D 4O, but frequently I only use 2U 3U 4U 4D and 4O as my usual take off from a stoplight. For a reference of driving with two sticks the videos in my signature will show you what its like.

I am the guy who came up with the bracket so that you can mount your clutch and brake pedal to the bell housing. This bracket is for the larger trucks not 1/2 tons. If any one has a interest they can call or email me, I can send pictures. 1-262-392-2989 or [email protected]

Marv.