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Wrap up on Trans & Overdrive


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This morning I took the 1947 Desoto out for a drive to test the rebuilt transmission and the overdrive.

It appears to be working as expected.

I did notice a couple of things. One is that is it a little sticky going into gears. The other is that the shifting of the OD is even smoother than it was before the needle bearing failure in the old OD planet gear.

I do have a very little drip in the gasket. I am not a fan of the Best Gasket Products.

I am using SAE 50 weight motor oil in the transmission, I had been using SAE 10W motor oil. That may account for some of the stiffness in the shifting. We will see once I get 100 miles on it.

The transmission is all but new. Every part in it, save a couple of minor items, are NOS.  Same with the overdrive except the planet gear assembly. The OD has a NOS Sun Gear and a NOS Ring Gear.

All the specifications as to tolerances are in the middle to low end of the specifications.

Time will tell. When I took apart the trans to deal with the OD failure, I found an entire tooth missing from the second gear as well as most of one tooth on the reverse idle gear. Yet the transmission itself worked just fine and made no noise. Go figure.

I have a second transmission with overdrive on the bench. I plan on assembling it in the next couple of weeks and crating it just in case I have a problem in the future.

The drive shaft universal joints, the new manufacture ones, with the block cups are not real nice. The Universal shaft company that I have used (through three generations of the same family) also though they were crap. I plan on taking a bunch of old blocks (cups) and sleeving them so they can be used on an off the shelf good quality joint. I have a spare driveshaft (Two with center bearing for long wheelbase cars) and will rebuild it and put it into a crate as well.

Do remember that we use the 1947 as out daily driver. I need to stock my own spares. The trouble I went through getting parts these past few months, as compared to 2006, is starkly different. The bearings that are not available or no longer made, the universal joints that are no longer made correctly in the USA, and on and on tell me we are at the tipping point I knew was coming. Parts are going to get exponentially harder to source from now on.

Thanks to all who helped both on this forum and in direct communication.


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Glad to see you back on the road after this project. Your attention to detail should give you an enduring result although in this game there's always another curly one around the corner. Have found much of the pleasure is in doing the project and overcoming the problems on the way through...as long as it gets to success at the end of course! Well done 😊👍

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I have driven the car a bunch in the last few days and the trans and OD are working fine. The sticking on 2nd gear happens sometimes and sometimes not. I do not think it is related to the oil as I am using 50W now versus 10W before. Heavy oil slows down the shafts sooner and usually improves the syncro action.


It may be a linkage issue, but I suspect that it is a syncro that may have a burr that needs to wear in. It is not doing it on the other gears.


The OD is shifting smoother then a modern automatic. Quite nice considering that the planet gear assembly is old and I could feel some wear in the non replaceable needle bearings. I am hoping that the new ring gear and sun gear will help lengthen the life of the old planet gear set.


I am going to take the car to my place out of town later in the week. That is a 160 miles round trip at 65-70 MPH most of the way. We will see how she does.



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