In late 2003 I started looking into which steering gear was correct for my 1941 Willys MB (slat grill)
After having read up on some compiled lists of slat grill differences I became a little confused. I ran across the line item " early ross gear less strengthening ribs". Of course, as with so many other slat grill parts, no one could tell me what this was. As a matter of fact, all of my questions regarding the different versions of steering gear went unanswered. 

I started collecting steering gears and pictures of stearing gears. I still don't have the answers I'm looking for but at least I can identify some of the gears out there now.

Let's start with what we know. The data in the TM's.

TM-10-1206 Change 4 Dec. 1, 1941
Group 1403
A-1239    Steering gear assembly--Less wheel (Ross Gear and Tool Co. No.              ).....1
A-740 x    Housing assembly (Ross Gear No. 503284)......................................................1
(the "x" means interchangable with Willys MA)

TM-10-1186 Change 1 July 1, 1943
Group 1403
A-413    Steering gear assembly--Less wheel (Ross Gear and Tool Co. No. T-13079)...MA......1
A-1239  Steering gear assembly--Less wheel (Ross Gear and Tool Co. No. T-13086)...MB......1
A-740    Housing assembly (Ross Gear No. 503284)..................................................MA-MB..1

ORD 9 SNL G-503
Group 1403A
7640-T-13086    FM-GPW-3504    WO-A-1239    GEAR, Steering, w/o wheel, assembly (RG-T-13086)...1
7640-503284      FM-GPW-3545    WO-A-740      HOUSING, steering gear, assembly (RG-503284)........1

Well, that didn't help much did it? The books make it look like the same housing was used on all MA's, MB's, and GPW's. And that just can't be right because we see too many variations in the field.

Before we talk about the variations it might be handy to put a name on some of the components and features of the steering gear housing. I don't know what the real name for these parts are so I'm going to make some up. Hope you don't mind.

Now that we speak the same language, let's move on to the different models.

But first a side note. I have three slat grills. they each had a different steering gear on them. One was "F" and GPW marked, one was Ross marked with no buttress, and one was Ross marked with a buttress. ALL appeared to have been on the jeep forever. With all that paint and rust etc. etc. etc. blah blah blah they just HAD to be original to the jeep. nope. To quote one of my all time favorite hit TV shows, "One of these things is not like the other. One of these things just doesn't belong."
I believe it is just about impossible to determine if a part found on a jeep was placed there by the factory 63 years ago, or placed there by an army motorpool 62 years ago.
but I digress....

So far there are two manufacturers of Steering Gear found. Ford and Ross.
Ford will have a script "f" stamp and "GPW-35xx" ( I haven't been able to make out the whole number yet.) on the mount plate. These appear stamped or engraved.

Ross on the other hand seems to like to emboss it's name on either the mount plate or the tunnel.

Features: No collar, but does have web and buttress. 
"f" stamped on mount plate. "GPW-35xx" on mount plate (I haven't been able to make out the whole number yet.) 

(not verified. may just be a trick of these photos)
Features: No collar, No web but does have buttress.

Features: has collar, web, buttress. 
"ROSS" and "U" or omega in box embossed on tunnel. "T122983" and "PATENTED" embossed on tunnel. All appear upside down if gear is placed on table mount plate down.
"T13086X" stamped on mount plate (last digit may vary, not verified). at least one has "3" stamped on top of tower.
This is the steering gear shown in most, but not all, of the TM's with drawings and photos.


Features: has web, but no collar and no buttress. Tower is thicker than ROSS#1
"ROSS", and either "U" or omega in box, OR "modified M" ebossed on mount plate (right side up)
"T122983" stamped on tunnel right side up

Internal difference: On some of these that I've opened up, there is a tube from the housing lower end plug on the bottom of the tunnel that goes up through the center of the worm gear. 
this part is not listed in any TM I have found.
this part IS listed in CJ manuals. CJ-2A's before serial number 178361 used the same horn brush and contact ring as the MB's and GPW's. after CJ-2A 178361, the horn wire continued down through the worm gear, and through this tube.
Before you start thinking this gear was only used on later CJ's, take a look at TM 9-803 figure 99 "Steering Gear, Disassembled". page 213 in my copy ( I wish my scanner was working). This picture shows a housing without buttress and collar, and with a thick tower. Most drawings in the TM's show ROSS#1 above.


My opinion:
Ford GPW's used a Ford GPW steering gear. (duh) The jury is still out on whether there is more than one model.
Willys MA's and early model MB's used the same ROSS housing. The MA used a different complete assembly because of the gear shift on the column. This housing would be the ROSS#1 above.
Sometime before the end of production, the ROSS#2 might have been used. I originally thought the ROSS#2 was only used on CJ's but there seems to evidence it was used on MB's.
During the production of the CJ-2A the horn wire was redesigned and a tube was added internally.

I now believe ROSS#1 was used on all slat grills and most of the rest of the MB production.

I still have no idea what "early ross gear less strengthening ribs" means. And I have no clue when the change from ROSS#1 to ROSS#2 might have occurred.

Feel free to email me with any information you might have!

Chris Fourroux

And then there are the covers! There seem to be at least a dozen variations of these. Maybe that will be a topic for another web page in the future.