1 Ton 230/6 Trans or Overdrive Options

[bumpside]

Hi everyone, I'm a new guy on the old Dodges, so bear with me.

 

Here' s the situation:  My 74 year old father is looking to gain some speed/gear ratio on his old 48/49 1 Ton flatbed dually with  the original (as near was we can tell) flathead six.  He's a retired truck driver so the 4 speed crash box (Warner T9?) is fine other than he's out of gear & rpm at 45 or 50 mph.   We live in SoCal and he wants to be able to drive to shows, etc. so there's a real need for another 10 mph or so.  Since it's the 1 Ton and he wants to keep up original appearances, there's no real expectation of a taller rear being available - or am I wrong?  He also wants to keep the flathead and a hydraulic clutch is not going to happen.  What are the options from the experts?

 

Are taller rear dif. ratios available for the 1 Ton rear axle?

 

Are there sources for the old style "2 speed rear axles" still?

 

I see from the factory literature that there were Clark 5 speeds avaliable that may have had OD in top gear.  Can they be found or are they like hen's teeth now?

 

A brownie box would be fine too but I'm aware of the lack of parts from my adventures with my oldish 60's Fords. 

 

How different is the flathead 6 trans mount from the later transmissions?  Will anything later interface with the factory bell without adapters galore?

 

I have a new level of appreciation for you Pilot House guys... After all the documentation I can find and have for my `67 Fords and `65 Jeep CJ5, this old truck is like sifting through a haystack looking for needles.  Anyway, go easy on the assumptions about specific brand detail knowledge please.  I've got the mechanical concepts and background down but I don't know jack for flathead era Dodges but I'm willing to learn to help my old man out.  So what say you?  Ideas?  Options?  Are am I just whistling dixie and dad's going to have to get used to being honked at on the fwy (again)?

 

Thanks in advance!

[41/53dodges]

You should try search for this one, overdrives are getting very common. T5 is the preferred swap, I did it myself over winter break. There is a kit available for $85 or parts are readily made with a lathe, just 2 spacers and a sheet metal aligning shim only needed for drilling new holes. Only downfall is the loss of the parking brake.

Good luck!

-josh

BTW,

Feel free to ask about the t5 in particular, search is unfriendly for finding short terms like that.

[bumpside]

You should try search for this one, overdrives are getting very common. T5 is the preferred swap, I did it myself over winter break. There is a kit available for $85 or parts are readily made with a lathe, just 2 spacers and a sheet metal aligning shim only needed for drilling new holes. Only downfall is the loss of the parking brake.

Good luck!

-josh

BTW,

Feel free to ask about the t5 in particular, search is unfriendly for finding short terms like that.

Yeah, the search was only somewhat helpful; as you noted T5 is too short to work and overdrive pulls up a massively long list of references to the other OD units for cars, etc.  After going through posts that looked vaguely useful and learning a lot, I was still left with enough questions to find it worth "starting from scratch" on suggestions. 

 

So the T5 is do-able with a simple kit?  I don't think the holes in the bell will be a fight and even the standard unit should be able to take torque of the old 230".  The Parking Brake should be something we can finagle one way or another...

 

So I'll start looking for the kit but I might as well ask... do you know who offered it?

[NiftyFifty]

Look to t5 swap or conversion, I think that's what mine was called. I did it and it was a simple job as long as you have a good drill press and a welder to cap off the one original hole that affects the T5 hole. I would honestly also recommend a rear diff swap to something with a better gear set, but being 1 ton you then run into my same issue of needing a new front axle to have the same bolt pattern for the rims. The 1 ton axle came in a couple ratios, but none made for highway cruising that I'm aware of. Even with the rear end changed the stock four speed ran too high rpm in my opinion so I swapped it after year 1. Be ready to change the drive shaft either way, my 1 ton had to be done and sadly because I did it in two stages I had to do 2 different shaft which came to a lot of extra $. Good luck and feel free to ask any questions, happy to help.

[Don Coatney]

 

 

So I'll start looking for the kit but I might as well ask... do you know who offered it?

Tom Langdon of stovebolt and innliners fame offers a T-5 kit for trucks. Google him for contact information.

[bumpside]

Thanks guys!  That's what I needed.  Looks like the stovebolt kit is cheap enough and I've found some links on the swap.  As much as I'd prefer the strength of the mustang T5, it looks like the S10 gear ratios and shifter position are better.  Then again, since we're only going to want to do this once, I think we might end up going with a "configured" trans with a forward shifter.  Either that or we grab both options from the junkyard and start swapping parts.

 

I do also appreciate the info on the rear end.  I'm sure that it will hold up to what he's doing and it's in fine shape, so that's not a big deal.  From a bunch of angles, it looks like it makes more sense to overdrive it than try to change it. 

 

Just for kicks, I'm also going to look into the "open shaft" or universal "divorced" gear vendors unit since my dad loves the old crash box.  It reminds him of his old 9 speed in the truck and a splitter on the 4 speed giving OD would work close enough to keep him there too. 

 

Thanks again guys!  As we bump into problems or discover anything useful I'll keep you informed. 

[Young Ed]

Been mentioned many times as an idea but I'm not sure anyones actually done it. Volvo apparently had some stand alone OD units that you may be able to use like a gear vendors but source at a much cheaper price. For a 1ton I'd look into something like that.

[Don Coatney]

Before you spend the cash to buy a T-5 I suggest you do some research on how you will do the emergency brake. Stock transmission has the e-brake mounted on the tail shaft of the transmission. This is not an option with a T-5. When I installed a T-5 in my car I also upgraded the differential assembly and connected my e-brake to the rear wheels same as a modern car.

[41/53dodges]

One big note here for the t5, you Probably have a four speed in that truck. Four speed bellhousings are not friendly, holes need to be filled and then drilled in new spots, a three speed housing just needs new holes drilled. In other words, you end up having to remove the bellhousing completely, which Is a pretty big project considering it holds up the back of the engine... I have a spare thats already drilled, but im in wisconsin and I somehow see shipping being rather spendy, but if you are interested send me a private message and maybe we can set something up.

-Josh

[41/53dodges]

Just another thought, how about an NV4500? Its a medium duty 5 speed used by GM and Dodge, I think some heavier trucks even had the parking brake on board. Would take some engineering, but worth looking into!

[HanksB3B]

What about just going with a taller final drive. A 3.54 or 3.73 from a Jeep Cherokee will get you the 10-20 mph increase. That's what I'm planning but only after I install a Rusty Hope Disc Brake Conversion Kit. Then I'll think about a T-5.

 

Welcome,

 

Hank   

[bumpside]

Thanks again guys!

 

The parking brake isn't a big deal.  I'm sure that we can fab up something to fit that on as I know people with lathes, CNC's, and other such fabbing experience.  Nothing a quick plate on or around the output shaft coupled with a cable actuated caliper won't fix.  Really, it's doable on way or another between what we can find in the "big truck" world and what we have on the back of this and an old 47 2 ton parts truck we have...

 

Which brings up the NV4500.  That is one of the other questions.  I had assumed that there was something problematic since no one else is using them in this kind of application.  They're common for so many other applications that are later, I figured there was something that was just a REALLY big problem with the old Mopar Flathead Six.  Ironically, my dad's DD is a 1997 2500 Ram extended cab with the Cummins and a NV4500, so we're well aware of them.  One of the questions I've had for a long time is the bell adaptability and input shaft length adaptability.  As I mentioned, I'm used to my blue oval stuff from the 60's; I can find specs for everything important on the NV4500 and all my Ford stuff like input diameter & length, trans/bell mating differences, etc.  but this post-war Mopar stuff is not easy to find documentation on.  It's getting to look like the easiest way to get it all figured out is buy a trans and use the extra six & bell we have to figure out what works but that's NOT simple for us to do "in house".  Plus there's the risk of buying the trans and finding out it won't work, so I'm a big fan of lots of research before going to the "OK, let's see how we can fit this together...". 

[41/53dodges]

What about just going with a taller final drive. A 3.54 or 3.73 from a Jeep Cherokee will get you the 10-20 mph increase. That's what I'm planning but only after I install a Rusty Hope Disc Brake Conversion Kit. Then I'll think about a T-5.

 

Welcome,

 

Hank

Works great on our little half tonners but Bumpside has a 1 tonner. Although a modern rear and such as a gm 14 bolt, only issue os width and original appearance. Could always make an adapter for wheels

[bumpside]

Oh, and thanks on the Laycock being available as a full divorced/separate unit.  I was always under the impression they were only available "married".  Since I have a friend that works on Volvo's for a living, I'll have to check into that.

[Young Ed]

Oh, and thanks on the Laycock being available as a full divorced/separate unit.  I was always under the impression they were only available "married".  Since I have a friend that works on Volvo's for a living, I'll have to check into that.

 

Welcome. post a pic of the 47 parts truck and actually your 1ton too.

[MBF]

What gears do you currently have in the truck and what size tires?    I think the rear choices were 3.9, 4.3, and 4.8.  If you have the 4.8 and were able to find a 3.9 that would be an almost 20% reduction in rpms at any given speed and you don't have to mess with pulling the engine or fabbing up a parking/emergency brake.  If you've got 6.50's on the back and went to 7:50's that would also make a difference.  Another thing to consider is a mid 60's Ford F350 rear for a V-8.  They have the same 6 lug pattern, and may come in a higher ratio.  I'm pretty sure the perches would have to be relocated, but that would still be easier than pulling an engine or fabbing up a brake setup.  If that swap were to work, I believe you'd also get the advantage of self energizing rear brakes.   Mike

[Merle Coggins]

I believe another option on the diff would come from the larger Chrysler, Imperial, and DeSoto long wheel base sedans and/or limos of the 40's or early 50's. I think they have the same larger diff that may work in the 1 ton trucks and may come available with better highway gear ratios.  

 

Merle

[ggdad1951]

I think merle is right. I dont they are that common though.

[Frank Elder]

I believe another option on the diff would come from the larger Chrysler, Imperial, and DeSoto long wheel base sedans and/or limos of the 40's or early 50's. I think they have the same larger diff that may work in the 1 ton trucks and may come available with better highway gear ratios.  

 

Merle

But you would have to salvage what you need, these bolt patterns are 5 on 5, also they may have a different splines.

Edited February 6, 2014 by Frank Elder

[Jeff Balazs]

Welcome Bumpside.......from a La Habra alumni. Go Highlanders! My folks lived off Beach and Imperial for years. As a youngster I worked at Burch Ford......gone now but quite a place in it's hayday.

 

Have you looked at Dana 44s ? Might find something that would work there? I think there is still a custom rear axle builder off La Habra blvd. That might be another option. I have a 3/4 ton with a Grand Cherokee rear........each model Pilothouse has differences that effect the install.

 

As you have already found out this group is the best resource for anyone with a Pilothouse. Doing one without it is just plain silly.

 

Jeff

[Merle Coggins]

But you would have to salvage what you need, these bolt patterns are 5 on 5, also they may have a different splines.

 

Frank, I was refering to the diff assembly only. Not the whole axle.

[Frank Elder]

Thats what salvage what you need means........and I didn't know if the spline count were different from car to truck diffs.

[wayfarer]

Not knowing which rear axle assembly is in the OP's truck I'll suggest looking at a 1½T  2-speed as a possible replacement. IDK if the wheels would be the same or not.

As for transmissions, in addition to the 4500 there are several lighter-duty units in the ½T trucks that could be useful but will require some rear engine mount fab work and likely a hyd clutch the OP says won't happen. These late one-piece transmissions require an adapter to the block and replace the oem cast iron bellhousing.

Again, not knowing anything about the existing bellhousing, consideration must be given to the depth of the bell vs the input shaft length if you mount a late trans to the bell. Is the t5 compatible at that point?

Additionally, let's not forget about Robert Horne's swap http://p15-d24.com/topic/17737-5-speed-not-t5/ using the  Toyo Kogyo 5-speed. It may or may not have the same input shaft length issues although the real issue is the spline to disc engagement not simply the oal and pilot bearing.

[MBF]

The two speeds for the larger trucks have even lower ranges than what he already has.  I've got one of each, a 1 ton, and a 2.5 ton.  The 1 ton is noticibly faster on the highway and the centers are no where near being interchangeable. 

[bumpside]

Not knowing which rear axle assembly is in the OP's truck I'll suggest looking at a 1½T  2-speed as a possible replacement. IDK if the wheels would be the same or not.

As for transmissions, in addition to the 4500 there are several lighter-duty units in the ½T trucks that could be useful but will require some rear engine mount fab work and likely a hyd clutch the OP says won't happen. These late one-piece transmissions require an adapter to the block and replace the oem cast iron bellhousing.

Again, not knowing anything about the existing bellhousing, consideration must be given to the depth of the bell vs the input shaft length if you mount a late trans to the bell. Is the t5 compatible at that point?

Additionally, let's not forget about Robert Horne's swap http://p15-d24.com/topic/17737-5-speed-not-t5/ using the  Toyo Kogyo 5-speed. It may or may not have the same input shaft length issues although the real issue is the spline to disc engagement not simply the oal and pilot bearing.

The 2 speed rear was something my dad has talked about for ages but they're hard to find in our experience.  The lighter duty trans might be worth it but the T5 is so easy to find, so easy to find parts both for the adaptation & upgrades, and so easy to find knowledgeable rebuilders on that I'd say the Mazda trans to be a poor bet for us specifically.   Thanks for the thought though, that's exactly the kind of idea I'm looking for - what works best,  you know?

 

The two speeds for the larger trucks have even lower ranges than what he already has.  I've got one of each, a 1 ton, and a 2.5 ton.  The 1 ton is noticibly faster on the highway and the centers are no where near being interchangeable. 

And that's what I wondered as well.  Since they are usually designed for a larger wheel/tire size, they are usually lower geared and I expected that they'd end up being slower than what he's got.  Thanks for the confirmation!