MTFCA Forum

Hi All,

My understanding is that the TTs came with either high speed or low speed rear end gears.

My questions are:
1) My truck is not in running condition yet. How can I tell which gearing it has by looking at the gearing?
2) Did Ford actually make both high speed and low speed rear end gearing in the 1920s? or is the high speed gears a modern day invention?

Thanks,
Jason

Ford made both the low and high speed gear sets. The low speed is a 7:1 ratio and the high speed is a 5:1 ratio. The 5:1 was a special order for high speed city deliveries and are so of rare in the standard Ford TT rear end. They are more common in the two speed Ruckstell rear ends. Search in google by "MTFCA Model TT rear end" and you will find a wealth of information. To check what type of gear ratio you have, jack up one rear end wheel of your truck, put the truck in 2nd gear, and hand crank your motor. Do not start it, just crank it. If you crank the motor 7 complete revolutions and the back wheel turns once, then you have the 7:1 low speed gear set. 5 completes cranks revolutions to one rear wheel revolution is the high speed 5:1 gear set

Hi, Jason. Let me make a small correction to what Steven said. Place the transmission in high, jack up one rear wheel just as he said. However, you should turn the engine until the rear wheel makes two (2) revolutions. On the TT truck this should be
5 1/6 turns or 7 1/4 turns. The number of turns is the ratio. Good Luck. Bob

What Steven and Bob posted is all true and is the easy way to tell what you have, but I must make one more qualifier comment. If the truck has a Ruskstell or an auxiliary transmission it must be in "direct" drive. If it's not you will not get either of the two results you are looking for.

Thanks for the information. Unfortunately my truck is stuck in gear and I have no idea what gear its stuck in. It needs a complete engine and transmission rebuild that has not happened yet. So the hand cranking idea could be confounded. Can I open the rear end gear box and look? What would I be looking for?

you should be able to turn the engine over and by watching the rear wheel, figure it out from this:

http://www.mtfca.com/discus/messages/41 ... 1404332259

On many of our Canadian sourced TT's a number is stamped on the cover at the back of the driveshaft on top of the axle to indicate the ratio. Was this not done on US production?

Allan from down under.

Jason, set the lever all the way forward. This is the high gear position. Very unlikely that your truck is stuck in low.