The Stovebolt Site Forums The Parking Lot Big Bolts 1941 COE Overdrive Transmission

Hello,
I'm interested if anyone has installed an auxiliary overdrive transmission in there COE. My truck is stock with a 216 and want to keep it as close to stock as possible, but it would be nice to have an overdrive gear to give the 216 a break at 40mph.

Thanks
Steve

It doesn't have enough torque to haul that big rig around as it is. Putting in an OD gear will kill it entirely, not "give it a break".
Jerry

Hey Hotrod, I have a rebuilt 261 sitting in a crate, but thats not going to help lower high rpm to low ground speed issues and the 216 is a nice running motor in the truck. I was hoping someone had some experience with a spicer 5831 or something else. Thanks Steve

Unless the area you travel is flat as a pool table, the 216 won't be able to handle the higher gear on anything but flat or downhill runs. What RPM is the engine running at 50 MPH or so? I'm considering replacing the driveline-mounted water pump in my 61 GMC fire truck with a 3 speed Brownie, but the 401 V6 will have enough torque to pull the higher gear ratio without getting below the torque capabilities of the engine. There's a reason the COE has such a low ratio rear axle- - - -the 216 just can't make enough torque to pull a higher gear with the heavy frame and bed of the average COE truck. They were made for load-carrying capacity, not speed.
Jerry

I totally agree with you Jerry. I maxed the truck out at 40mph and the 216 was screaming. I thought that it would be nice for the 216 to have an auxiliary over drive box to to utilize that OD gear on the flat land I live in. Then as needed shift into third to climb a hill. No loads hauled in this truck, purely for fun. Thanks Steve

Bigger tires will get another 5 MPH or so. I get about 40 MPH plus on mine with 7.50 x 20s , wish I had 8.25s on the back, but this way I'm sure I'm going to get stopped if I need to and I'm not in that big of a hurry.

Mine could easily pull a higher gear, it's a '57 LCF stock 283 V8 2 bbl., SM420 trans and 7.10:1 rear end. Even with 100 bales of hay on it it's not struggling, right now I have 8.00x22.5 0n the rear, I'm looking for 10.00x22.5 and it should help a little.

78buckshot, 10’s might too big for your truck. You are lucky to have 22.5 wheels, they are getting hard to find. Your truck probably came with them. The ones I have are 5” wide which makes 9 x 22.5 tires a tight fit.

StevePala, look for a Brownie while driving your 216, when you get one installed, put your 261 in.

Ed

The 8.00x22.5 rear tires were the stock offering for your truck, the 10.00x22.5 were the max optional size tires. Stepping up to the 10.00 should give you a little faster road speed, but will also change the calibration of the speedometer.

Your 283 when new produced 160 HP and 270 pounds of torque, the OP's 216 in his 1941 COE made 87 HP with 172 pounds of torque...there's a BIG difference between these two!

Mike B

Another thought would be a Clark overdrive transmission. I don’t know all of the ins and outs but I recall there being a few different options that would be a direct replacement mostly while keeping a stock appearance. Clark 207 VO?

Steve, is this for pleasure driving? I would wager if your just pleasure driving ect unloaded the truck with a 216 that’s properly tuned can handle the overdrive.

I have a 46 Chevy COE that I’ve dreamed about putting a overdrive in. Keep us posted.

The trouble with a Clark or any other like OD transmission is they got the OD location from third gear, so when one is wound out in second gear, direct is next which isn’t too big of a deal with a two speed rear, but with a single speed, and when hauling a load, one is usually stuck in second when climbing a hill, very frustrating.

If one never hauls a big load, and doesn’t drive in the mountains, it is OK.

Ed

The ratios on a Spicer/Brown-Lipe 6231A are: 1.24 low, 1.00 direct and 0.87 overdrive. I believe the 5831A is similar. The A suffex is important. The B and C are not progrssive and give like a 2:1 low or other less useful variation.

With a small engine you can work a big load up through the gears by keeping the engine on-the-boil. The RPM drop between gears is around 400 RPM. A 13% overdrive is not such a big deal to pull as a 30%. Aside from the ratio problems, a Clark 5-speed is difficult to get parts for these days I'm told at the ATHS antique truck show a few years back. Someone there suggested that I convert to a 10-speed roadranger but I've already got 12 speeds, 9 road gears and 3 compound ratios.

Sorry to once again butt in here with stupid questions .. (AKA, the cold hearted Reality Fairy) but ...

As the guy who sits in the driver's seat of this web site and forum, I've heard a LOT of suppositions over the last 25 years from guys/experts who are chasing the same unobtainium -- faster speeds out of a big truck with the 216 (i.e., "I want to stay as original as possible but still get highway speeds).... i.e., "IF you do this ... If you try that ... If you do some other rube goldberg cobble up thing ... you can have your cake and eat it too."

What I have *yet* to hear is any definitive and documented feedback from someone (anyone) who has done something (anything) to make a big truck with a *216* (not a 283, not a 235 or any other higher torque/higher HP engine) be able to drive at modern speeds (and hold them, even on hills and accelerating with traffic) on modern roads and be satisfied with the results. Not ONE. In 25 years!

Heck, I tried this with a 1-ton and couldn't do it (tall tires, 4.10 gearing. Didn't try an aux OD but I can't see as how it would have made any difference). I gave up on the 216 and went to a 261 and life has been great ever since.

As many of you never fail to point out, I am no technical expert on any of this. Got it. You may feel free to move on to a new topic. However, I am not completely dense, either -- I see and read most of what crosses this web site over the years. And from what I read, I have come to conclude that making a bigger truck with a 216 enjoyable in modern traffic on modern roads at modern speeds is not possible within the bounds of our current understanding of Physics and Thermodynamics. It is a waste of time, money and effort to try. And I think we do a real disservice to the hobby to even speculate on ways to do it.

Bottom line -- If you want to make the 1-ton or larger truck enjoyable/driveable you have to lose the 216. Disagree?? Show me some proof.

Has anyone ever tried adding a turbo?

John

Shouldn't be in a hurry, enjoy the old time drive. If it was good when your truck was built it can be now! To me the more original the better!

A guy name Ray Beasasie made speed equipment including turbochargers for Chevys 70 years ago. He built several pretty radical cars. He must have not sold many and I do not know of one that survived. However, just because it can be done doesn't mean it should be done.

https://photos.app.goo.gl/cTcAnyX4juw7oN2y8

That's wild, I don't agree though, I think someone should try it. Perhaps not me though a babbit bearing 235 probably isn't best for forced induction 😀

Oh please ... stop ... you're killin' me.

You shouldn't say things like that, John -- You'll give Jerry evil ideas. He's already engaged in doing unspeakable things to a 216 as we speak ...

"BWAHAHAHAHAHA!" The mad scientist sitting on my shoulder and whispering in my ear just got a big laugh out of that suggestion- - - - -Turbos are great for little engines with wannabe delusion of being big engines. Adding forced induction to a glorified tractor engine would be about as successful as finding a chicken with lips! Even using a Rootes-type blower on a 292 is only done by people who like their smoking material to come in a long-stemmed pipe in a predominately Asian neighborhood!
Jerry

The problem with Clark or other’s OD trans. is they use the third gear position for the OD location, so one goes from second to direct with nothing between, very difficult, even with a two speed rear, especially with a load, so be careful in considering similar OD trans. Have to weigh advantages of OD vs. stuck in second ‘til top of hill.

Ed