TT Ruckstell Gear Ratios

[Tom Hicks]

I can not find a chart that also includes a Warford overdrive.

I notice that it refers to "Ruckstell Low" and "Ruckstell High". I had thought that Ruckstell high was incorrect terminology as a Ruckstell is actually 1:1 when in high, right?

I also included an old engine RPM/speed chart.

I can't say I understand it all, but it looks like a TT with 5:1 rear and no Warford should cruise about 30 mph.

I don't know Jim Thode, but I thank him for making the chart.

[Adam]

I restored a TT fire truck that weighed 3,300 pounds, had a balanced & blueprinted engine & trans, and the TT high gears with ruckstell. It could easily cruise up to 35 on flat ground, but that was pushing it a bit too hard. It seemed to be at its best in the 27-30 mph range. This was the speed where the engine wasn’t excessively lugging or racing and where I would expect the best longevity. Hills that didn’t require a downshift with a touring car did require Ruckstell low with the TT.

My TT dump truck with the regular low TT gears and 6.00-20 tires runs about 18-20 without over revving it. With 7.00-20 tires it probably ran closer to 25.

[Mark Gregush]

You are ether driving with Ruckstell under drive gearing engaged or you are not. When you are in Ruckstell, you are in under drive high/low/reverse, when you are not in Ruckstell you are in normal Ford high/low/reverse. The terms used have caused a lot of confusion over the years. Makes a lot of people think it has a higher ratio, which it does not.

[A Whiteman]

Yes, like Mark says, the Ruckstell is either 1:1 ('Ford direct'), or it is in underdrive. It is 1:1 in the sense that it does not change the Ford standard ratios in 'direct'.

The Ruckstell operating instructions actually refer to the gears as 'Ford' and 'Ruckstell'.

The idea of using the terms 'high' (direct) and a 'low' (Ruckstell underdrive) is understandable but it is misleading.


There are 2 different worm gear rear diff ratios, but these are actually the standard Ford ones.
This confuses things a bit as they are also known as 'high' and 'low' ratios - even though they are actually both pretty low !! You have to physically break down the diff and bolt in the different worm/crown wheel sets to change gears, so this is not really an option when 'on the move'

30mph is almost too fast for a standard diff ratio in direct. It was designed to go a lot slower than that.

The purpose of the Ruckstelll is to help get heavy loads up and down hills and over rough ground. The underdrive is really good for that. It also helps when driving along the field when loading the back with produce (nice and slow) and also getting in the garage nice and steady without hitting anything (well, that is is your garage is as well packed as mine!)

[Tom Hicks]

For clarification of correct terminology:

I was driving my TT when I came to a hill I had to climb which was too steep for Ford High so I shifted into Ruckstell. Once over the hill and back on the flat I shifted the Ruckstell back to

a. straight drive
b. direct drive
c. out of Ruckstell
d. ...

[Ruxstel24]

D...Ford high.

As I understand the second chart, a TT Ruckstell is 1.60:1 reduction and a T is 1.54:1.
So with 13-39 gears, Ruckstell would be 4.54:1
And 3:1 in high. Correct ?