Don’t make fun of me. It’s probably dumb. I’ve had this 47 Chevy loadmaster 2 ton for 4 years. Just now road ready. An old guy asks me if it had a 2 speed rear axle. What??? In all of my research and reading and working on the truck to get it ready I hadn’t heard of this. Ive had it up to 30 mph in top gear and it feels like it’s screaming.
So I just checked my shop manual. I don’t have a selector switch on the dash. Not surprising as the truck was in pieces when I got it. I don’t see anything in the book that tells me what I can look for to let me know if it is a 2 speed axle.
The 2-speed axle should have a diaphragm, or solenoid on the housing near the driveshaft. The actuator can be a pull button attached to the stick shift. I had a '58 Viking with vacuum actuator that included a hose to the speedometer. It shifted something so the speedometer would still be accurate in low. My '55 6700 has an electric actuator.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Got it. Thanks. So I should probably assume 30-35 mph is it? It’s not a big deal. It’s a rural backroad to get to shepherdsville and that’s as far as I’ll go anyway.
My '57 with single speed rear 7.2:1 ratio will do 45 mph topped out against the governor, the book says that's at 4000 RPM, I don't think your rear axle would be worst than mine.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
The two speeds are usually "slow" and "really slow!" Those rear ends were used to get maximum gross weight loads moving, and pulling steep hills where the number of gears available could be effectively doubled to minimize the wide gaps between transmission gear ratios. 216's and early 235's didn't have a great deal of torque, so they needed lots of gears. Another option on the big rigs was a "Btownie"- - - -a 3 speed auxiliary transmission between the main box and the rear end. Most of those boxes offered an overdrive ratio to increase road speed when running unloaded. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Later model rear axles can be substituted if the wheel bolt pattern matches, but one will loose some low gear use, I have used Brownies to solve this problem.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
If you haven't already done so, have someone follow you in a modern vehicle just to verify how accurate your speedometer is. You still won't be winning any races, as you already know, but you may be going a little faster than you think you are. Of course the reverse could also be true!
If you haven't already done so, have someone follow you in a modern vehicle just to verify how accurate your speedometer is. You still won't be winning any races, as you already know, but you may be going a little faster than you think you are. Of course the reverse could also be true!
You can use a smartphone and download an app to check your speed. If you don’t own one, I’m sure you can get one of your younger acquaintances to do so for a ride in your truck!
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
At 43 I’m not too old yet. Some days it feels like it. Really appreciate the help and tips. It’s been 100 degrees here lately so I haven’t taken it to town yet. Soon as it cools a bit we will take the maiden voyage. It was my grandpas truck. His nickname at work was popeye so I thought that was fitting for the trucks name.
Another option for speedometer checking would be a GPS unit. If the truck runs a 6 volt electrical system there are inexpensive voltage doublers available that can handle the minuscule current draw of a GPS. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'm a flip phone guy so I don't have all that stuff.
I only brought it up to suggest that maybe at some point the truck may have been fitted with tires a size or two larger than it was born with. If that were the case he might be going 40 mph even though the speedometer only says 35.
AT&T just sent me a new flip phone free of charge, since they managed to figure out the one I've been using for the past few years was about to become obsolete (Now, tell me they're not spying on us!)When I went to one of their stores to get it activated, the whole crew gathered around to marvel at the old phone. It turns out it was manufactured in 1986, and most of them had never seen one that old! I bought it used on Ebay for 20 bucks at least 10 years ago, and swapped the SIM card from an even older phone into it. It was still working well to make and receive phone calls, and receive the occasional text. No, I refuse to try to send a text with that tiny keyboard, and I've got a real computer and a real camera for all the other things a lot or people try to do with their phones.
Aren't "smart phones" for dumb people who think they have to have an electronic umbilical cord hooked up to cyberspace 24/7, and are willing to pay outrageous sums of money every month for the privelege? Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Aren't "smart phones" for dumb people who think they have to have an electronic umbilical cord hooked up to cyberspace 24/7, and are willing to pay outrageous sums of money every month for the privilege? Jerry
Yup! At least in many instances that seems to be the case.
Ok, now that we've all gotten *that* off our chests, we can return to the subject of the thread, Ja?
~ John
A kid raised on Hotwheels, Matchbox and Tonka cannot be reasonably expected to own only one vehicle as an adult.
1949 Chevrolet 3804 In the Legacy Gallery | In the Gallery Forum 1973 IH 1310 Dump 1963 Kaiser M38A1 2001 International/AmTran RE3000 "Skoolie" 2014 Ford E-350 4x4 (Quigley)
OK When I first got my 46 2 ton running. Didn't have the vacuum lines hooked up to the diff. yet. I was sure it was in high range but it went really slow so I got under there with a vise grip and shifted it and it when even slower. By the way I have NO CELL PHONE. Never have had and never will! I hear a lot of people [censored] about them including my wife! Sorry John
I'm assuming that the "Btownie" is actually a Brownie? "T" & "R" do reside right next to each other on the QWERTY keyboard!
My only experience with the Brownie gear splitter was on 275 and 400 HP International semi-tractors and there were actually four speeds on those: "underdrive", "drive" and "overdrive" for routine driving and an "under under drive" that could be handy for really slow maneuvering in a crowded yard. But that gear's real value was in recovering from a missed double clutch when upshifting the 5-speed main tranny. The Brownie could be shifted so effortlessly and quickly that even when pulling a significant grade the "under under drive" could still be engaged at an engine speed within the useable torque range; then up through the Brownie gears again to a successful double clutch on the 5-speed main tranny. Did Brownie make a model sized suitably for the gutless little 1 to 2 ton Big Bolts? I'd LOVE to have something like that on my '52 Big Bolt dump truck!
Currently, my only Stovebolt is a 1952 Chevy dump truck. My non-Bolt trucks include two 21st Century Chevy S-10s, an '02 extended cab ZR2 and an '04 crewcab LS both of which are four wheel drive. I also have a 1956 Chevy 3100 that is currently undergoing a frame off restoration, Resto-Mod style. My non-GM trucks are a 1941 International K-7 5 ton dump which was custom converted to all-wheel drive and a 1996 Ford Powerstroke 4x4. I haven't owned an automobile for a number of years now. If the opportunity should present itself I'd definitely like to acquire more true Stovebolt trucks, and even cars ... one can never have too many.
"Brownie" is a generic term for auxiliary transmissions in general, not just the ones manufactured by Beown-Lipe. They come in all sorts of torque ratings and speeds. I've seen 2, 3, and 4 speed auxiliaries, with manufacturers such as Eaton, Spicer, Fuller, and others, including Brown-Lipe. The most common ones I've worked with are 3 speeds, with under, direct, and overdrive ratios, paired with either a 4 or 5 speed main box. I've got two on hand right now, one big honking box suitable for a Diesel rig, and another, lower torque unit that would be right at home in a truck somewhere in the 1 ton to 2 1/2 ton range. I had ideas of putting the smaller box into a Ford F-350 motorhome behind a 460 engine and a C-6 automatic to get a little better gas mileage. We retired the camper before I got around to making that conversion. The big box is headed for my 1961 American LaFrance fire truck, replacing the driveline mounted fire pump. That rig has a 401 GMC V6 and a Clark 5 speed with direct drive in 5th. gear. I'm planning to remove the rusted-out fire bed and install a commercial 5th. wheel and a gooseneck trailer hitch for heavy duty towing purposes. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Brownies can be identified by the numbers stamped on the ID tag. 5xxx and 6xxx series are most useful for our size trucks. 7xxx and higher are so large, they need to on a semi tractor. The leading number, 5 or 6 in the above cases represents the Engine Torque ratings for the input engine. There are 3 and 4 speed ones. When searching for one, make sure and get the shifter mechanism from under the cab of the truck. None are synchronized, however they shift easily.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
Ijblue Your 47 2 ton should run faster than 35 mph without much struggle,does it have an OK muffler ?? May just sound bad. My 51 with 2-speed will cruise at 50 .
I just joined forum and had to add to this topic. 52 1 ton. Just bought it and on the ride home I was in 4th and the truck was doing around 35 ( my son was following me), yet I didn’t have it floored either because she sounded like she was already high in the rpm’s. I was told from seller it was a Logging truck. So I’m guessing this is true as to why it is geared low. These roads are 30-35mph anyway and I should be good. I did have a line of cars behind me though! So I guess I’ll stay off the main roads and cruise. (photos soon) sambo
What size wheels and tires does your truck have? I ran a 59 1 ton (3800) for several years, with a 4.56 rear end gear and 18" wheels. It would run 50-55 MPH without doing any engine damage, although it did sound a little noisy at those speeds. The 216 and early 235 engines, one of which your truck probably has if it's original, were designed to run considerably more RPM than people who drive later model trucks are accustomed to hearing. Just for grins, try removing the fan blade and make a highway run. I think you'll be able to get a better understanding of where the noise is coming from. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
What size wheels and tires does your truck have? I ran a 59 1 ton (3800) for several years, with a 4.56 rear end gear and 18" wheels. It would run 50-55 MPH without doing any engine damage, although it did sound a little noisy at those speeds. The 216 and early 235 engines, one of which your truck probably has if it's original, were designed to run considerably more RPM than people who drive later model trucks are accustomed to hearing. Just for grins, try removing the fan blade and make a highway run. I think you'll be able to get a better understanding of where the noise is coming from. Jerry
Jerry, What RPM are you thinking? Our 6400 261 engine turns 2600 range at 46 to 48 mph. 55MPH is pushing 3200 RPM's. That said, I like to keep it below that. We put about 160 miles on it Sunday to a show.
I believe the 261 was HP rated at 3600 by GM. I really doubt that they would specify a destructive speed range to rate the engine in their specs, particularly when the big rigs had gear ratios and governors that allowed then to run at full throttle all day every day. The problem is not with the engines- - - -it's with the snowflakes with sensitive ears who are driving them these days! As I suggested, try a run without a fan and compare the noises you're hearing to what you normally experience. I think you're going to find that the frightening noises are actually external. I'd also suggest at least temporarily fitting a tach to see what the real RPM is at various speeds. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Thanks Jerry, yes, we did install a tach, so those numbers are good. I calculated them, and GPS confirms the numbers.. I agree that GM probably wouldn't give that spec if it didn't intend for it to operate at those speeds. Really 55 is fast enough with this truck. I do feel more comfortable at those speeds and RPM.
Do you know what type and model this diff is? I have the same one in my 59 and I need inside wheel bearings and am trying to find a part number, a no I do not have the ones that came out of it too look up the number
ljblue My 48 2-ton has that same set-up with a babbitt 235 it's not very fast,haul 8000 lbs. white rock with it spread on the driveway. My engine has a "48" cast right in the block below the distributor. Does your 47 have a "47" cast in there ?? It's just above the pan rail.
