The Stovebolt Site Forums The Shop Area Driveline 1941 model AK 3:55 rear gears

I have a 1941 Chevy 1/2 ton, model AK in which I have been having trouble finding good quality 3:55 rear gears. On the first set, the mounting surface of the ring was unevenly machined and full of chatter marks. On the second set I’m having a hard time setting the backlash. I took readings from seven different spots around the ring and came up with six different readings .010”, .014”, .013”, .015”, .011”. 011”, and .008”. My target is .010”. Ring gear runout is .0015”. The carrier bearings are preloaded.
What are your thoughts? Has anyone had this issue before and what did you do? Does anyone know where to find good quality gears that can be set up? Does anyone know of a set of NOS 3:55 gears for sale?
Any help would be appreciated.

Well the average is .01014, so maybe you are close? (Sorry, not trying to be a smart A.) I purchased my gears over 20 years ago and not sure where to get them today.

NOS 3.55:1 gears for a 41 Chevy???? I don't think so.

I don't know if you're talking about axial runout or what so I'll assume the worst. Please make sure you are dealing with perfectly clean surfaces on the back side of your ring gear and where it mounts. A bit of anything can cause this to happen and I exclude nothing...one grain of sand will do it, a nick or loose shaving will do it...anything at all (even grease from your fingers containing dirt, etc). Anything that might lift one side of the ring gear higher at all. Since we have no idea if the numbers you gave us are starting at .010" and rotating clockwise or counterclockwise and ending up at .008" that's a question mark for us but please remember a sheet of common copy paper is .004" thick. Also...and I mean no disrespect at all...are you using a very good dial gauge? I'll assume the answer is yes, and I'll assume .008" is the low point and a bit of schmutz is diametrically opposed to that (somewhere around where the .015" reading is). That's where I'd start my witch hunt. Good luck!

As a side comment, these numbers you gave us are not really all that bad. If your target is .010" and everything is perfectly clean, I'm not sure I'd make too much of a problem out of it. My rear end came from a 1969 Chevy pickup and if I had backlash of .040" I'd be dancing around the block singing but it works okay.

Sorry...I meant to say .008" is the high point and not the low point. That's where it is possible for something to be located.

Where did you purchase the gear sets from? Did you send the first one back for a replacement? I purchased my set from Chevs of the 40’s last Black Friday on sale. I hope I don’t have any similar issues when I do the swap the end of October.