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Does anyone know if the trucks that came factory with tandem axles in the later 1950's were all drive axles, or were there some with a rear dummy axle?

From what I have found they were drive and no tag alongs. Spanky should have a better answer at this point. I am collecting more books etc. but, at this point they were drive axles unless someone did a custom job.

If the tag axle was added, would that have been done somewhere other than Chevrolet, and how would you tell what kind of axle it is?

Chevrolet trucks did not have a factory tandem axle
(that I have seen or read about), either tag or driven, for the AD years 47-54 for sure, and possibly not even for the next several years?
-Edit: I have seen a factory 56 Chevy tandem with both driven axles, even admired it and took pictures.. didn't remember the year until the very same truck was brought up a few post later..

GMC did have tandem setups on the biggest trucks for the same years.

So, what year, size, and make truck are you interested in?

I have looked for a long time and this site is the only information I have ever found about them. The truck I have is a 1955 6400. The rear axle is a tag. I know now that it was done later because I just found the manufacture name plate on the frame. They did a excellent job of legenthing the frame because I can't tell where they extended it. It looks all one piece. It looks to have hauled cars at one time with the bed that is on it. It still has the inline 6 engine, but I believe my Dad said it has a 15 speed. That wouldn't be factory would it? It has 2 drive shafts, one coming from the transmission going to a smaller transmission, maybe a power divider?? then another going to the front rear axle. What is the popularity of the tandem Chevy even if it isn't factory?

Hy Brandon 721, true Chevrolet tandems started with the 56"B" production, the same design continued until 1959, hope that helps.

Hey Brandon,

As 3B said, Chevrolet started producing factory tandems for the 1956 model year and were available on the 10000 series trucks. In 1957 they also became available on the 8000 series trucks. They used a pair of 15,000 pound Chevrolet rears with a 3-speed power divider. The power divider had two "underdrive" gears (2.22:1 and 1.22:1) and direct. The power divider also allowed the operator to switch from dual drive axles to single drive on the fly. The rears could be either 6.17:1 or 7.20:1 ratio. The transmission could be either the Spicer 5-speed or the 6-speed Powermatic. Power steering and a 4-barrel carburator was also required equipment.

I have seen a picture of a 8000 series 1957 and I have seen in person 2 different 10000 series units...not to many of them around.

FYI, my information only covers the Task Force trucks 1955 thru 1959.

Mike B

When they added the rear axle, would the transmission and gearing stay the same that came with the truck, or would they change it to accomadate the extra axle and weight? If I get a picture taken I will try to upload it, so you can see it. Are there a lot of trucks around with the added tag axle, or are they kind of rare?

My 1954 5400 series Chevrolet COE had a Trucktor chaindrive Tandem conversion. The trailing axle actually had it's own frame rails that slid over the factory frame rails all the way under the cab. The factory axle was then mounted to this glider type frame, ahead of the tag axle, with the end results here, http://rides.webshots.com/photo/1115990817052570246iKfhhf . There were several other companies along with Trucktor that did these conversions for Chevrolet. They were Truckstell, Truxmore, Grico, Fabco,& Thornton.

Though I would share a photo... http://good-times.webshots.com/photo/2877323940034994936ofRtDb?vhost=good-times...
The name plate on the frame shows it is a Fabco build.

If both axles are "live" and are connected via drive shafts, not chains, then both rears need to have the same gear ratios. If your truck has the "standard" SM420 4-speed transmission it should be upgraded to a HD Spicer. The SM420 isn't strong enough to handle the torque and loads that the added rear allows the truck to carry. I don't believe Chevrolet sold a factory built tandem with a 6-cylinder either...only V-8's, again for the higher torque rating.

Mike B

No, my truck doesn't have the drive rear axle. It's just a tag along. How do you tell what kind of transmission is in it??? Anyone out there have a truck with the added tag axle? Wondering how the power is with a 6 cylinder???

If you have a 4 speed it's more than likely an SM420. Search for SM420 on google, then see if you're looks like the ones you find pictures of.

I think you will find very few Chevy trucks like yours with tag axles and original 235, 216, or even 261 six cylinders.
These trucks could be loaded to more than the engine could comfortably handle with just one rear axle, add another and you still don't have any more power.
So if you load your truck to the capacity allowed by the tandem rear axle setup It should handle it but you will be going very slow.

Personally I can't see the need for a tag or tandem axle setup on a 2 ton Chevy; a larger GMC would have been a much better answer at the time, and still today.

Grigg

My '54 Chevrolet Trucktor Tandem Conversion had the original 261ci. 6 cylinder, coupled to the original SM420 4 speed transmission. The only thing I could find on it that was different than a average 2 ton truck, was it had a larger brake master cylinder. Find yourself a Chevrolet "Silver Book", for your year model. These are large catalogs that contain Different manufacturers that supplied bodies, other equipment, & accessories for New Chevrolet Trucks, when purchased. These catalogs have complete pages devoted to these Tandem Conversions. They show up on ebay, from time, to time. Also check your swapmeets for them. Check www.autolit.com , for them also. Maybe if someone on here has a Silver book, they could scan you the Fabco Tandem page. I have a couple of the Silver Books, but don't have a means to scan the pages for you. Any year close to 1955, should work for you. I have 1952, & 1953 Silver Books.

In the late 1950's and early 60's I can recall seeing a few dual rear axle rigs with a very large "V" belt sandwiched between the dual wheels, connecting the front and rear tandems. I can't imagine it would have transmitted much power, but one of the problems with tag axles in general was the tendency for the driven hub on one side to get lifted off the ground and lose traction while crossing a dip in the pavement or some other type of irregularity in the road at low speed. Having even a slight transfer of power to the tag axle might prevent getting stalled when negotiating uneven pavement.
Jerry

Any more pics of your truck??? You might have a truck that had a tag axle added for a specific purpose.

Here is another picture...http://thumb16.webshots.net/t/66/566/7/29/30/2831729300034994936PuCqKy_th.jpg
The axle was no doubt added to haul whatever it carried. The bed that is on it, other than the wood top, is welded to the frame. There is a second 3 speed muncie transmission in it, also probably added. My great uncle who had it, (don't know if he is the orignial owner) used to haul grape boxes from his vineyard on it. Hope to one day get around to fixing her up...
Love the picture of that 56'

Sorry for the photo not working. Lets try it again.
[IMG]http://thumb16.webshots.net/t/66/566/7/29/30/2831729300034994936PuCqKy_th.jpg[/IMG]

The fender emblem looks like one from a '57 model, are you sure its a '55? Back in 1957 my dad had several '57 Chev. tandem dumps with a 'dead axle' tag. They were 6000 series and were too light for what he had them doing, hauling 16 ton payloads of stone. He put together (not a factory job) an extra axle with hydraulic brakes and a reyco type spring suspension. The trucks had manual steering, 283 V8 and 5 spd Spicers, and a 15,000 rear. I can't imagine driving one of them today. Dad said they held up quite well considering the load. The main problem was the occasional broken wheel. The wheels were 6 lug stud piloted buds and 8.25 X 20 bias ply tires. The trucks had 12 foot Daybrook dump beds with extra high sides and short wheelbase. Most of the weight was carried on the tandem. The front axle had extra springs to hold the weight but the axles were the original 4500 lb. type. I'll try to find a few old pictures of these trucks to post.

JAMES

Has a '57 model hood on it also. What's the number on the ID (VIN)plate say.

My Chevrolet brochure "Chevrolet Advance Design Trucks for 50" shows two tandem axel trucks with conventional cabs. It also has a COE version.

I thought it might be a 57' also, but I ran the VIN on the VIN buster, and it came back as a 55'.

The VIN is VW2550015278
This is on a silver plate on the inside of the door frame. Down below that is the Chevy blue plate that lists the truck as 18,000 GWT and gives two engine options either the 261 or 265.

Do you plan on fixing it up or ??? The truck looks pretty solid from the your pictures.

I probably can't give it a full restore, but I do want to at least get it back in driving condition. This truck is very solid and heavy. It has a pair of monster leaf springs in the rear.

Whats the history of the red 56'? I don't believe I've ever seen one like that restored. Looks great....

Look forward to seeing you get it drivable again. Keep us posted.
The 56 tandem was found in a junkyard about 16-17 years ago. It was in good shape overall. I have only seen one other Chevy tandem in person besides this one. The truck has been to many shows across the USA and has been on the Route 66 fun run twice. It is fun to drive but slow as heck.
Good luck on your truck.

I'm sure I saw the 1956 Chev. tractor at the ATHS show in Greensboro several years ago, it was my favorite! I believe it had an automatic trans. I was most impressed at how new and original it was. I seem to recall it came from Arizona. So you are now in Charlotte?

JAMES

Yes, The tandem was at the ATHS Greensboro show back in I think 1996 or so. The truck only needed fresh paint and some cleaning up. It has the original 322 V8 with the 6 speed automatic. The truck is based in Arizona at my Dads shop. I live in the Charlotte area and work in the motorsports industry. We hope to have it down in Huntsville, Alabama this May for the truck show.

That's neat, I first saw the truck in Colorado Springs and took several pictures of it, I have yet to see another like it. I was parked about two rows behind you with a 61 f350 I had at the time.

Can you explain how the power divider is shifted? What gears or choices does it have?

Thanks,
Grigg

Brandon 721: Can you get some more pics of the tag axle setup?? You have something fairly unique and hopefully it won't take too much to get her operable.

Grigg: The automatic transmisson has 3 forward gear positions and a neutral position and a reverse position.
Low(1-2 gear) Intermediate(3-4 gear) High(5-6 gear)
In Low, the truck will shift once and hold second gear
In Intermediate, the truck will shift 3 times and hold 4th gear
In High, the truck will shift 5 times and be in 6th for traveling.

The power divider has 2 jobs: a 3 speed aux. transmission and a " transfer case" to engage the back axle.

The cab of the truck has the auto tranny shift tower and selector. A conventional park brake hand lever, and 2 additional shifters. One selects the gear for the aux. tranny (1st,2nd,3rd) and the other engages the back tandem. You select your aux. tranny gear and put the shift tower selector in one of the 3 forward positons depending on conditions. Once on hard ground or paved highway the auto tranny can be put into High, the aux. tranny can be shifted into high( which automatically kicks the back axle "out of gear". The back axle can only be engaged in two lower gear selections of the aux. tranny. At this point it is just like driving a modern day pickup. Mash the gas pedal and go. I hope I helped!!

Grigg:
I did not make it to the Colorado Springs show. Sorry to have missed you. Would love to see your pics if possible. Are you going to Huntsville???

I also saw the Chev tandem at Colorado Springs but don't have any photos of it. I seem to have lost most of the ones I had unfortunately. Here is a link to my 49' Chev crane truck with Truckstell tandem either. Hope it works.

http://pic40.picturetrail.com/VOL366/751691/21297735/349693795.jpg

Here is a photo of the rear axle setup.

[IMG]http://thumb16.webshots.net/t/52/552/5/56/63/2122556630034994936nDxNTf_th.jpg[/IMG]

Here are about 5 pictures of your truck (right?):
Start with this one http://good-times.webshots.com/photo/2916646400080251109tDpxcP

What are the ratios in the power divider/auxiliary transmission?

I will be at Huntsville one way or the other. I hope to have my 48 together enough to legally drive it down there and back, I still have to put the sheet metal on before I get to that point.

Grigg

Grigg,

The power divider has two "underdrive" gears (2.22:1 and 1.22:1) and direct (1:1).

BH, I saw you truck at Hutchinson, my 57 Fire Engine was parked about 5 truck away from you.

Mike B

Brandon 721: Thanks for the "up close" photo of the tag axle. Keep us posted on the project.

53 Moneypit: Thanks for your photo of your "Heavy Chevy". Where did you find that???

Grigg: Thanks for the access to your pics as well!! Mike B. is correct on the power divider ratios. 1st(2.22:1) 2nd(1.22:1)and 3rd(1:1 direct). The rear axles have a ratio of 7.20:1.

I have not been able to attend any of the national shows for the last several years due to work. My Dad and my uncle usually take the truck(s) to the shows. I plan to be at the Huntsville show in May. My Dad has a bunch of pics of Mikes 10500 fire truck. It was one of the first "other" 10000 series truck he was able to see in person. Maybe I can give Mike B. and Grigg a cruise around Huntsville if they are able to attend attend the show!

BH, Sign me up for that ride in Huntsville...I'll be there! You'll put a grin on my face that won't go away for a looooong time!

I'd love to add a 56/57 tandem to my colection...someday.

Mike B

Just wanted to add this bolt. Don't see many of the 10000 series task force trucks.

http://sfbay.craigslist.org/nby/cto/979812267.html

To bad that trucks on the Left Coast and I'm on the Right... !

Did you notice that it has the original looking 2-sticks for the Power Divider and that it has the Powermatic (Allison) 6-speed automatic trans? That would make a neat car carrier

Mike B

The two raised ribs on the hood are also a tell-tell sign it's a '57. Just my two cents.