The Stovebolt Site Forums The Parking Lot Big Bolts Any to get more speed

I finally got my 53 6400 two ton on the road. That's definitely a red letter day. Is there any way to get a little more speed out of this thing that doesn't involve putting a mortgage on my house, changing the motor, or rebuilding the entire truck. Probably not, but just thought I would ask. Allen

Are your running 825-20s? Maybe you could run 900-20s?

Next choice is overdrive or auxiliary transmissions.

The most cost effective, but not the easiest is to look for a spicer auxiliary trans and put it where your carrier bearing is now. Make sure you get the shifter stuff, too.

Check out Jolly\'s informative page

The easiest way in my opinion and middle of the road price wise is an Advance Adapters Ranger Torque Splitter Unit. Goes in front of your SM420, puts another lever in the cab, moves your SM420 shifter back 7 inches and requires you to take 7 inches out of the driveshaft. You probably don't want another lever in the cab. Cost about $1500. Ranger Torque Splitter

Big money = Gear Vendors or US Gear.
Gear Vendors US Gear
I have a US Gear, but I lucked out and picked it up for cheap.

Mitchell made a gear splitter at one time for medium duty trucks and rvs, but I have only seen one and have been unable to get any information out of Mitchell, not sure they are still in business, think someone is manufacturing earyly F*rd stuff under the name.

Lastly a Dodge NV4500 5 speed with a Dodge to Chevy bellhousing adapter kit. I have seen this done, it is slick. The price of the transmission drives the cost on this one and its a fair amount of work.

Any of these will put you in the 65 mph top speed with comfortable cruising at 55 instead of 45.

You could try to find a two or three speed brownie Aux. trans. for this purpose.

what are you talking about in speed????45 to 55 is about all you can expect and have it live...doc

sorry didn,t address the question,,,if it dosen,t have a 2 speed find one,,if it does stay off the freeway and enjoy...doc

doc,

a 2 speed rear end does not gain you any on the top end. The high gear in a two speed is about the same as a regular rear end. The low gear is a two speed in about 20-30% lower allowing you to split gears.

Hey 4.3,

That's not always true...you can find 2-speed rears that have better high gear ratios and give about the same ratio in low as the original single speed rear. I did this on my fire truck. It has an Eaton rear and I just replaced the center pumpkin. I went from a 7.17 single to a 6.14/8.36 2-speed which gave me a lower low and a higher high. I gained 10 mph and now run in the low 60's all day long. Total cost fot this was under $400 ($250 for the rear and $100 for a drive shaft and about $50 misc).

I think this is the cheapest way to gain speed while keeping the pulling power to haul a load.

Mike B

Mike B, that's cool.

The charts for Advance Design Big Trucks I have do not show that as an option. It shows a 53 2 ton could have 6.17:1 for a single speed and 6.13:1 and 8.10:1 for a two speed. This happens to be the ratios in my Art Deco truck for some reason. I guess knowing what is your truck is always a good start. These are available in the service manual, somebody posted about it being online somewhere.

Do you know which eaton pumpkins interchange? Will the pumpkin from a Task Force fit the really early stuff? Will the 60s eaton pumpkins fit? I'd love to get some slightly more usable gears.

My Chevy 4408 '49 1 1/2 ton has a 3 speed Browny that is a late '40's model. It is a 41M-1. Spicer had these made by Watson Transmission after WW II. I got info from Transmission Technologies Center about the unit and they were even able to supply me with the official drawings for installation in '48 Chevy and GMC trucks so I guess it was an approved aftermarket upgrade. Chevy never offered this option in their official product lines as far as I konow.

Hey 4.3,

I took pictures and drawings with bolt hole counts and measurements to my local BIG truck junk yard and they knew exactly what I had and pulled the pumpkin right off the rack. I don't know what years are interchangable, but would guess there are many. You more than likely have a GM rear on your truck and your available ratios with that are very limited.

I still think swapping in a complete Eaton 2-speed with the right gears would give the same results as putting in a Brownie Aux Trans for a lot less money. Just need to get the same wheel lug patteren.

Mike

I will post a pic to show you I have an early eaton and maybe you can let me know if it is the same bolt pattern as yours. Then we can confirm that art deco and task force eatons have the same bolt pattern.

What years did GM make their own 2 speed rear with the small 10 bolt pattern?

My point is that if he has a stock 6:17 rear in his 53 2 ton. He will gain no speed by swapping to a 47-54 2 speed with 6:13 high gears and 8:10 low gears.

The truck is a 53 6400 two ton, but I'm almost positive the rear end and two speed is from an earlier truck. When I was working on the brakes I could not find new cylinders that looked liked the ones I took off. After going over the shop manual I found that the cylinders are like the ones from 48 or older. (I think I have the correct year) The back plates had fittings for cables to pull the emergency brake, while my truck has the emergency brake on the drive shaft.

I could not find new or rebuilt cylinders, and ended up having the old ones sleeved.

Thanks for the suggestions, but I think most of them are over my head. For now I'll probably live with it as is, and maybe think about something at a later date. I wasn't looking for a lot of speed. Just enough to keep from holding up traffic like a school bus. Thanks Allen

I was able to gain some road speed by going to 900-20 tires on my 53 two ton wrecker like 4.3in84toy said.It is still slower then everyone behind me wants to drive.It also has a Watson three range and two speed rear for low end power.Built to pull,not for speed.