Are 4 speed and automatic speedo gears the same????????????????

[duster360]

I need a speedo drive gear for my 4 speed. Will the 4 speed and automatic speedo gears interchange?

 

[Wolfy2U]

I have a friend who own's a transmission shop and whenever I need a new gear, or to get the correct ratio gear, I talk with him and he gets me the correct one. Different colors mean different ratio's. Tire size and rear end ratio can change the speedometer by quite a few mph. I had a 73 Road Runner that I changed the rear in and added taller tires, it threw the speedo off by 7 mph. Luckily Sam knew just what it needed to correct it! So I recommend talking to a local tranny shop (that knows their stuff) about it.

 

[d55dave]

Yes, the gear, aluminum housing and I believe retainer and bolt are interchangeable from I think 66 up. As you probably know you need the right tooth count gear to match your rear tire size and gear ratio. Also the housing has to be clocked at the right position to match the speedo gear at installation, see the service manual for details.

 

[duster360]

Good to know they will interchange. The one in the 4 spped I am building is shot. I have 3 727's with good gears, so I will use one of those if they are close enough in ratio. Thanks.