[Richard]

I have searched my files, my receipts, and my notebooks. I cannot find the specific model number of the TRW box. Mine was EXTREMELY difficult to read. It is printed on the bottom on the box as you would see it from the ground. It is on a raised boss, that is ground flat. Your info may be different from mine, but once I found the number, I learned no exchange replacements were available, which led me to rebuild mine with a kit from Wellman. https://newellgurus.com/showthread.php?t...ND+rebuild

Getting the box in and out is hard, rebuilding is pretty straight forward with help of the manual which is already linked above.

I spoke with an engineer at TRW who informed me the box was built for Newell, but declined to answer what was special about it. He really did not want to deal with a DIY guy.

Jack,
Since you are happy with the way the coach drives, maybe you want to look at a few things before you decide what to do. First, if you turn the wheels all the way in one direction, do the steering spindles hit the mechanical stops? If they do, then you are experiencing the abysmal turning radius of a 45 ft Newell. There is a reason they went to a steerable tag. If it is not hitting the steering stops, then I would investigate resetting the poppets on the steering gear box. It may not have been set up correctly to begin with.

If all of that looks ok, you may want to just evaluate a longer pitman arm before you replace the steering gear box. Mine is 10 1/2 OAL, 8 1/2 C to C on box mounting hole to drag ling mounting hole, 1 3/4 thk, and 2 1/2 wide.

I am conscious that there is a close relationship between the internal steering gear ratio and the length of the pitman arm in terms of the steering wheel turn to the steer tire turn.