MTFCA Forum

This spring I finished building a Model A pickup from parts and pieces. It has a '36 flathead, '39 transmission, hydraulic brakes, and lots of other early Ford stuff. It is a blast to drive. It is so much fun that my TT has started gathering dust. For fear of losing too much interest, I think that I need to make a change to it in order to add a little more utility to it.

Currently, it has a high speed rear with a Ruckstell and a rebuilt stock engine but with domed pistons for a little higher compression. My top speed is about 28 mph. I would like to bump that up to a comfortable 35 - 38. I am thinking about an aux transmission with overdrive but desire to have one like a Rocky Mountain or Moore that mounts at the rear to keep the driveshaft rpm's down. Does anyone have any good experiences with any particular brand and, more importantly, does anyone have one for sale in good condition? (By the way, my TT also has original A-C accessory brakes)

My TT runs a rebuilt engine with SCAT crank and high compression head. It is well
balanced, with express gears out back. I can do 35-40 all day on flat ground. What
is limiting your top speed ?

Brent, the tt rear axle gear ratio limits the speed to about 25. The ruckstell provides under drive which will not increase vehicle speed.

All other things remaining equal, a high speed gear set will gain you about 8 or 9 mph over the low speed set. My engine is stock with a functioning magneto so 1600 rpm is about the maximum speed for mine. 40 mph would run mine over 2100 rpm...this would create some turmoil in my crank case and maybe a little outside of it too!

I believe that a significantly higher “net” rear axle ratio would not gain you much in “cruising” speed. I liken it to my experience of installing a 3-1 rear axle ratio in my otherwise stock 27 roadster. On a level road with favorable conditions certainly it went a little faster. Through in some uphills and a head wind and I was down in low Ruckstell and definitely slower!
Most TT’s are fairly heavy and have significant wind resistance.
So if you want to go faster build a more powerful T engine. I would start with the bottom end (improved crank and oiling). Camshaft, cylinder head and intake system. With counterweights and pressure oil a T engine can easily turn over 3000 rpm (actually 4000 is quite possible)

So, does anyone have any relevant experience with a rear mounted TT auxiliary transmission? I appreciate the other input but Scat cranks and balancing aren't in the cards.

I have a Rocky mountian 6 speed to put in my TT.I am not sure my engine is up to it. Its rebuilt with cast iron pistons, only upgrade was S.S. valves. Im running a high speed gear set and a Chigago 3 speed. It tops out about 40mph. Cruising speed is 28-30. Can maintain speed in T high and Chicago high unless its a steep hill. The heavy 8in1 bed and tall wood cab may be holding her back a bit. About as aerodynamic as a phone booth. I also would like to hear about the rear mounted trans.

It's not a rear mounted auxiliary transmission, but my TT has a Muncie. It provides under, direct, over and reverse. I have a low speed set of rear end gears and a less than perfect stock engine which in planetary high Muncie over I can coax up to about 33 MPH. With a high speed set of rear end gears I suppose 40-42 would be achievable, probably a little more with a stronger stock engine.

I really like my Muncie in spite of the fact that t growls loudly in under and reverse, not as much in direct and hardly at all in over. I haven't had any problems with drive shaft vibrations even though the Muncie speeds it up. All in all I recommend it.

I just happen to live in Spokane, home of the Antique Auto Ranch. Some of youze
may follow the Montana 500 racing .... ? These are the guys from the Ranch. They
know T's and they know how to make them run smooth and fast.

I walked into the Ranch after I got home from my last deployment and told a disapproving
Tom that I wanted to get a TT and "drive the wheels off it". He humored me to some
degree, but I could see in his body language that I was being dismissed as another idiot
that did not grasp the limitations of Model T's. Especially TT's.

After I showed up at a Tuesday night meeting (every Tuesday night except during Montana
500) with my truck, I think he began to take me more seriously and when I asked questions
about how to get it over 20 without shaking it to death, he basically said what Les just through
out. Speed from a TT is a multi-pronged attack:

1. The engine needs to be balanced and parts used to increase power, because ...

2. The higher "express" gears might let the truck go faster, but the stock 20hp will
dog out badly on hills or with a load.

3. Then there are other things like brakes and wheels. When a TT goes faster than Henry
intended, other problems arise like stopping and cornering.

This is what they advised and what I did:

I rebuilt the engine after a rod bearing failure and made the following mods:

1. A painstaking balancing of everything we could.

2. SCAT crank, C-race cam, oil dippers, high compression head, and OF carb. The carb has
still not been installed.

3. I broke down the Ruckstell and did a mix-n-match of best parts, tossing a set of express
gears in there while it was apart.

It took a while to work the bugs out. I was used to easy starts and free starts and the new
engine was tight and fussy for a while. But once it broke in, it was smooth running and capable
of easily pushing the old dog down a flat road at 35-40 all day long. I've clocked it twice, really
wound out at 48.

Also in the plans is a Lincoln 3-speed to raise that cruising speed. The math says it should take
my 35-40 to 50+. We'll see. Currently, the truck is largely sidelined, due to no time, on account
of I need to finish my house. The wheels were getting loose and sketchy, so my focus turned to
building a new set. The OF carb is rebuilt and coupled to an Anderson intake, waiting on the work
bench. I have a mostly built turn signal system also waiting for me to find the time to complete
it.

The idea has always been to have a TT that can travel distances, because I love road tripping and
live in the ultimate T-driving land on earth. So far the work done looks to be getting me toward
my goals. If I could just keep life from getting in my way, I'd be out wandering the backroads of
the west ....

Contact Jeff Cordes. His TT will run 60 mph.

Well, about thirty five plus years ago, I had a TT with an all wood body that I restored. It had a "Universal" direct and overdive rear-end mount transmission. IT WAS GREAT! Easy to shift. good increase in gearing (5 in, 7 out). The truck also had a Ruckstell and 5 to 1 gears. I routinely drove it at about 40 mph with a just a stock engine. I will add, that we had real gasoline in those days. This garbage sold today has about 25 percent less mileage, with less power speed and performance. Stockish model T speedsters I know that would do 70mph in the '80s, can only do 60 mph today.

I have had a couple other "Universal" (the brand name, not the application) three speed progressive shift under/direct/over transmissions in model T cars. They are fairly common for the TT trucks, but I never used one in a TT. The ones for the T cars were also very nice, and easy to shift. A "Universal UDO I used had a very tall overdrive ratio. I don't know what the numbers were for the Rocky Mountain I had, or others, but the overdrive in one of my cars was 1 turn in, 1 2/3 turn out! I used it with 4 to 1 rear end gears and top gear was plenty high! I don't know what they are for the TT truck versions.