The Stovebolt Site Forums The Parking Lot Big Bolts INFO WANTED - Lempco Gear Catalog

Hi bolters,

Looking for someone with a Lempco Gear catalog from the 1940's tha could look up a part number for me. Ive searched the interwebs for an online version and have completely struck out. The Lempco company grew in the 20s, 30, and 40s by buying up other manufacturers. I think that is the case case with their gear division. I have a NOS ring and pinion, still in the Lempco box. The gear has no mfg. name, and where I would normally expect a stamped partnumber, it has been ground smooth. and the Lempco number electric penciled by hand in its place. I even wonder if they were buying surplus NOS bearings from the government post war and marketing them as their own?? The numbers are 5372, and 5373. There is a hand writtin tape note on the box indicating 1940-46 GMC & Studebaker (Army). I am just trying to find something a little more authoritative then a hand written note on a piece of tape...

It's a longshot........


https://www.daytonlamina.com/contact

What is the gear ratio, and inside diameter of the ring gear ?

looks like ~38 tooth ring gear & 7 tooth pinion for a 5.42 ratio

i could be off a tooth or so on my count.

I am pretty sure the ratio is 40:6 or 6.67, but I'll double check that today. It is the same size as the ones in my 1-1/2 ton. My 1-1/2 ton G506 uses H110 banjo axles.

Standard ratios for 46 are 5.14 (36:7) for 3800, 5:43 (38:7) for 4000, and 6.17 (37:6) for 4000 (optional) and 5000 - 6000 trucks.

Ring and pinions are typically always matched with even teeth on ring with odd on pinion or vice versa. That's done so there's no repetition of tooth contact.

Here's the page for the rear axle out of the 46 Vehicle Info Kit

I have no disagreement with what you have posted, but also note those models are their civilian truck models. My Chevrolet G506 1-1/2 ton came with 6.67 gears which were sometime in its life replaced with 6.17 gears. The tape label on the box also noted 1940-6 GM & Studebaker ARMY. I added the emphasis as it seems important. I have also attached a couple of new photos to answer quesions regarding tooth count and also inside diameter. They are ring gear (40 teeth), pinion gear (6 teeth), gear ratio 40:6 or 6.67:1. The inside diameter is approximately 7-1/4"

You are correct, those axle ratios I posted are for civilian models.
I just counted 41 teeth on your ring gear picture (three times). Your pinion is definitely 6 tooth, so I get 6.83 ratio on my calculator. Kind of makes sense as military stuff is LOW geared.

I guess I don't know what to tell you about the ring tooth count. I have started at the tooth just right of the wire, and counted clockwise (5 times now). I consistently get 40 teeth.

Here is catalog sheet for H110 axle standard gear sets.

My 3rd set of eyes counted "40" on the ring gear, if that is of any help???

Any chance you want to take a stab at any of the tricks or tips in this "Tech Tip" Reading Indented Numbers to try and better ID what you have.

You can still see some of the stamped numbers on far left and right as the grinding wasn't complete, and one of these tips might bring more into view to help???

Just a suggestion.

Dan

I just counted 41 again.

OK, I recounted a couple more times and get 40. AND it says 40-6 on the box in your first post. Must be the phase of the moon or something that made me get 41. That's my story and I'm sticking to it.

I'll go away now.

You know, I've read that 40-6 probably 30 times or more, and in my mind I read it as years... not gear ratio.
Now that you mention it being the gear ratio; I just realized the years mentioned on the box are 1939-40.

This is why I have been trying to find someone with one of their catalogs. There is an ebay seller peddling a photocopy version, but I just don't want to spend $30 plus postage for a copy...$$$

Maybe the guy selling the catalog would be willing to copy the page with your gearset on it for a few bucks.

6.67 is the same ratio of the gearset used in my CCKW (G-508). The one in your images looks a lot like the gearset used in the corporate (aka "banjo") axle used in some G-508s and all G-506s.*

The odd part is the "Studebaker" reference on the box. The Army's 2-1/2 ton Studebaker US-6 used a different driveline, which was made by Timken and was of a totally different design. The ring and pinion sets are not interchangeable.

Best Regards...

*Edit.

After looking closely at the TM, this is not true.

Ring gear on the corporate axle has a wide shoulder on it, to provide contact area for the thrust block. The ring gear in your image does not have this feature. Sorry for any confusion this might have caused...

CrowbarBob, your first impression I believe is correct. Like you, I am confused by the reference to GM AND Studebaker on the tape. This ring and pinion look nothing like the illustrations I've seen for the Timken axles used on Studebaker US6s and some split axle CCKWs.

The set is virtually identical to the set from my Chevy G506. The shoulder you mention is just the surface opposite the ring gear teeth. This ring gear, including the back thrust screw surface, looks just like my G506 ring gear except the number of teeth.

My quest for the Lempco catalog was primarily to assure myself that it is correct for a GM banjo axle and NOT a Studebaker US6. I have a couple people interested, and one of them owns a US6. I would hate to sell it to him then find out it doesn't fit🤔

Hi 1942-G-506,

If you get a spare moment, can you post a pic of the backside of your ring gear? Attached is a better image from the G-508 TM of just the ring gear. The area near the edge to accommodate the thrust block is clearly visible.

Also, just for reference, attached is an image of a Timken pinon gear. After looking at it, I think that it is safe to say that this gearset will not work in a Studebaker US6. Although, I'm not sure there were any other Studebaker products made that could have used the Chevrolet designed axle.


Best Regards...

Here is the back and front, complete with the locating dowels as shown in your illustration.