garrbw

Look for help with driven gear and drive gear. I have a 62 4 speed and I can't get the speedometer to read. I can run the speedometer by attaching a drill on the cable at the transmission. So I know the cable and speedometer is working. I have changer the driven gear out and still no luck. Can anyone tell me what's wrong or what I am doing wrong. Also is there anything inside the transmission besides the drive gear on the main shaft?

Thanks

62vetteman

I'm assuming that when you say 4 speed you mean the factory B-W T-10. It used (3) different speedometer drive gears with different diameters. It used a 6 tooth 1.92" dia. gear, a 8 tooth 1.84" dia. gear and a 8 tooth 1.72" dia. gear. You possibly could have a mismatch of the drive and driven gears. For example a 1.72" drive gear and a driven gear meant for a 1.92" drive gear. That is a .100/ side difference so the gears might not be meshing. autogear.net has a T-10 catalog that has a listing of what driven gears are to be used with their respective drive gears.
I would disconnect the speedometer cable at the transmission. Gently insert something ( small screwdriver, old speedo cable end, etc. ) into the driven gear and see if you can turn it. Obviously if you can the two gears aren't meshing.

garrbw

I will try it. I assumed the driven gear was correct. Thanks

garrbw

So I did exactly what you suggested. I inserted the gear and used the old cable to try and turn the gear. It would not turn. I used a bore scope to view the inside as best I could. I could see the drive gear. What I think now is that the keeper on the drive gear may have come off. I hooked all back up and when I put it in gear you see the speedometer jump up every once in awhile. Let me know if you have any other suggestions. And yes I have a T10. Also I will look on the website to see what gear I should have. I need to be sure what gear I have in the rearend. I am going to try and call the previous owner to see if he can tell me before I pull the cover.

62vetteman

I checked the '61 Chevy service manual and the '62 supplement. The drive gear should be steel if it's original and is a "press fit". It doesn't use a spring steel type clip like the plastic type gears. Is the drive gear centered in the hole for the driven gear? In other words did it move out of position on the main shaft. The only other thing I can think of, is that the drive gear developed a crack/ split and lost the press fit on the main shaft. This could allow the gear to spin on the main shaft. Maybe you can do a closer inspection of the drive gear with the borescope while turning the driveshaft. If you can't get a good view of the gear with the borescope, the HF Feb. flyer has a coupon for a color remote camera. It's half price ( $70 ).

JohnZ

There's a "large" and "small" steel DRIVE gear pressed on the output shaft, and two corresponding families of "small" and "large" plastic DRIVEN gears that mesh with them (large with small, and small with large). Small and small won't mesh at all, and large and large will bind up. See the tech tip below for all the details.

garrbw

I took another look this afternoon with the bore scope. It is a metal gear. I used a small magnet to verify it. Also I was able to get a small screw driver inside to see if I could move it by praying it. I couldn't move it. I received a new driven gear today to ensure that I didn't buy one that wasn't quite right. Tomorrow I am going to install it and verify it is turning by using a piece of an old cable.

garrbw

Thanks for the tech tip. I will print this and keep it for a reference. I did determine that my drive gear is metal. I am going to determine tomorrow if I need to pull the tail piece or not. Thanks again for the input.

Solid Axle Guy

Anything new to report yet?

garrbw

Had to work late. I plan on doing it tomorrow. I will let you know what I find.
Thanks
Billy G

Pilot Dan

The NEW repro driven gears (Muncie style) are SHORTER than the originals (t-10 style not available) used in your transmission. You will need to add the small shaft extender piece (sold by some vendors) to the new gear end for it to work properly otherwise it won't be long enough to reach your drive gear. Bet that fixes it for you. Pilot Dan

garrbw

Well I can not believe that a simple job is eating me up!! I verified the drive gear is turning. I installed the gear in the transmission and used a piece of old cable in the driven gear. Had the car started put it in gear and not only verified that it was turning but grabbed it with a pair of needle nose pliers. I couldn't hold it ensuring that it wasn't slipping. I hooked up the cable and the speedometer was bouncing. So I pulled the cable off and drove it with a drill and the speedometer ran fine. The cable is 62" bought fron Ecklers. I am thinking now the cable is to short! I am going to see if I can buy a universal cable and cut it to fit. If that doesn't do it I'll burn the car!! Simple job wow

Solid Axle Guy

Hang in there bud. This stuff can drive ya nuts at times. I'm having some issues with my 62 speedo, cable & maybe gears too. That's why I'm keenly interested.

garrbw

Well I finally got it. I can't tell you what I was doing wrong because I don't know. I went to work on it this morning with plans to replace the cable again. I ran the cable with the drill to verify the speedometer again. After that all checked out I checked the cable at the transmission end and could not see anything wrong. I hooked it up just I have before and the speedometer worked like it never had a problem. Don't why this time it worked but it did.
Thanks for hanging in there whit me. If you need help with yours send me an email as I don't get of the website every day.
Thanks Again
Billy G.

Solid Axle Guy

Sweeeeeeeeeeeeeet. I feel ya man. We've all had those moments when we want to start destroying things. I'm happy for ya.