My speedo driving gear in my muncie 4spd is worn out, it has a valley in it and will not turn my speedo cable gear, which is a 22 tooth (I believe) 4:10 ratio rear. I ordered a new one from Rick's but it does not fit correctly, it is too big for the driveshaft. The guy I ordered it from ask me what color the old one is and I said white so he sent me a white one that does not work. How do you know what size driving gear you need as they make more than one size? I don't know which size to reorder and I sure don't want to screw up again. Thanks for any info.

Im having a speedo gear problem too....
I am converting my 69 from a TH-350 to a Muncie M20. I was told that the speedo gear from the TH-350 would work, but it does not engage. I believe the diameter is incorrect. The transmission is a 65 muncie M20 which has a pressed on steel speedometer drive gear. Anybody know the correct diameter speedometer gear???? the Rear end ratio is 3.55 :confused:

As I understand it speedo gears should be interchangable between all 1st gen camaros with 3 or 4 speeds and powerglide and TH350. I think the TH400 is the one with the larger diameter gear.

The problem with selecting by color is not all manufacturer's use the same color coding. Classic Industies says for a 4.10 rear the gear is a (7.00 7.35 x 14)GM with 22 teeth. No color is given. In another catalogue no diameters are given and there are two different 22 tooth gears listed one one green and one silver. I'd say the Classic industries listing is more reliable, but remember, if you aren't runnung stock height tires your speedometer is not going to be accurate.

Hope this helps, and please someone correct me if I am wrong about the gear interchange.

Victor

The muncie trans used a few different size drive gears(on mainshaft) made of steel or nylon. They also had about 10 or so driven gears(in speedo bullet). You have to use the correct size driven gears with the proper drive gears. Large drive gears with small driven gears and small drive gears with large driven gears. The 39879XX series small diameter(25/32) driven range from 17T-22T, the 38603xx series large diametet(7/8) driven gears range from 22T-25T. As Victor stated the 22T comes in both sizes. If you post your rear ratio and tire diameter I can give you the part numbers you need. You can also use this formula
20168/tire diameter=?
? x rear ratio x 8= ??
??/1001=driven gear tooth count

hope this helps

Ok i do not have the original driven gear that was in the muncie.... so i have no reference point. The gear that was in my TH-350 is light brown in color or maybe clear????? has 24T and is not 7/8" in diameter and it does not mesh with the drive gear inside the transmission. I assume that i need the larger 7/8" gear

Rear gear ratio is 3.55
Tires are 265/50/15

69CamaroRS/SS your driven gear falls between 22T and 23T at 22.44. The part numbers for the Large diameter driven gears are 3860345(22T) and 3860346(23T). You will want to use a small diameter steel drive gear 8T part number 3708145. The driven gears you can still get at the dealer the drive gear you can get from Larry at D&L http://www.dandltransmission.com/

Thanks for your help....

Im gonna go with the 23T gear
The Muncie has a steel drive gear, which appears to be pressed on, is it most likely a 8T gear or did they come with different tooth counts ???

as long as it meshes with the gear and spins the speedo, I can get a box to correct the error.

Thanks again

They did make a 7T and 6T drive gear in steel. The 6T is 1.92" OD, the 7T is 1.76" OD. So make sure you have a small diameter 1 3/4(1.76) OD steel drive gear 8T to go along with the 23T you are going to use.