Jumbo Giant Transmission?

[colonelpowers]

I was talking to a fellow today who has an old Jumbo Giant Transmission that he might sell. I searched the forum for some information and found a lot out but I wanted to see how you can identify the different models. He said that he had no idea if it was a 333 or 666. Is it stamped somewhere so I can tell him where to look? Does anyone have any good pictures to compare it to so I could try to make sure this one is complete if I run over and check it out? Were they good transmissions? I read that they were pretty noisy but I didn't find where anyone had any long-term experience using one.

Thanks and God Bless.

[Wayne Sheldon]

I have a couple of them, actually three I think, but one has some serious water damage to the lower cluster gear. I have never had one in a car or driven a car with one. Several people that I have known with them liked them very much and a few even preferred the Jumbo Giant to the other more common makes.
The biggest problem with them is that they used a special front coupler/adapter that made installing them easier than some of the other UDO transmissions. I cannot offhand recall what the thing is called, they are still manufactured for other kinds of machinery, but not made to fit the model T. The adapter slips into the back of the model T's transmission, with a precision fit and a coupler disc that makes aligning and bolting in the transmission easy (supposedly?). MOST, nearly all, of those couplers did not remain with the transmissions when they were removed or stored, and became lost. Finding the original couplers is very difficult, and often sellers want a bunch of money for them because they know you aren't going to walk down the aisle and get another one.
The couplers can be made if you know a good machinist that will work for cheap? Otherwise, they can be expensive to have made!

[Adam]

Finding the original couplers is very difficult, and often sellers want a bunch of money for them because they know you aren't going to walk down the aisle and get another one.
The couplers can be made if you know a good machinist that will work for cheap? Otherwise, they can be expensive to have made!

The 2 coupler parts need to be properly hardened or they won’t last. One part is simple, the other is more complex. If you can find a competent machinist for $50/hour (cheap these days), you could probably expect to pay $300-$500 for those parts after material and heat treating. Also, there is a special spring that fits inside a hole in the “u-joint” half and bears against the freeze plug in the driving plate that has sort of a custom shape you’d may need to have made too.