Transmission

[James_Douglas]

I wanted to write a quick note to everyone who has been following my transmission saga over the last 24 months. I am working on a larger document --- look for it in a month or so.

I have now put two weeks on the fluid drive 3-speed transmission with BW-OD driving around San Francisco in heavy traffic and I have taken two 100 miles plus round trips out of the city with a lot of freeway running.

So far everything is working as it should. The overdrive has not missed a lick and it shifts very nice. In the overdrive the only parts other than what was delivered originally is the balking ring and the gear it rides on. This part is NOS and it makes a big difference in how the OD feels when it shifts.

I would urge anyone rebuilding one of these OD units to consider having a shop spray weld the groove that gets cut into the gear by the balking ring or have it hard chromed back to proper size. This is the only part changed in the OD and it is working fine now. Because it works on friction it has to be correct. See the BW manual on how to test one.

The transmission is so quiet it is amazing. New gears, new shafts, basically new everything except the input shaft and gear. Paying attention to the end-play specifications, using new shafts and small bearings (previously all the small bearings/shafts used were pitted) seems to make a large difference in smoothness. For the low price of shafts and bearings it is a no-brainier.

The fluid in the fluid drive is working better than at any time since I purchased the car.

The original fluid I had in the car was, I think, the original factory fluid. No doubt the additives had degraded over time as the oil engineers have confirmed that they will. The ATF and 10W motor oil which I have also run has about the same feeling as the old fluid. I now know that ATF has things in it that are not good over the long term for the carbon-graphite seal ring. I would never run that fluid again.

The oil I am now using, MOBILE DTE Light Circulating Oil ISO 32, has improved the feel of the acceleration from a standing stop to 10 MPH. Since I do not have access to a chassis dynamometer I cannot provide a hard analysis. I can say that on the hills here in San Francisco the difference is very noticeable driving the car. Car friends who ride around town with me regularly notice the take off improvement as well. (I found the cooperate successor to Gyrol Fluid Drives and had a nice talk with their senior engineer)

I also changed the motor mounts while I was at it. I took out the NOS mounts I put in three years back when I did the new engine. I put in a set that were re-done by Steele. The rear-uppers were about 1/8” shorter than what came out. The front was a little thicker than what came out. The odd vibration with clutch out and in gear standing still (On the fluid coupling) went away with these mounts.

Well, that is about it. Thanks to everyone who provided thoughts, ideas, and support. I can now see every part of these units in my sleep.

Best, James

[greg g]

Well it seems your long uphill push has finally yielded results you were looking for. Congratulations on your perserverience and effort. I know the hills of San Francisco can make uphill driving seem a Sysiphian enterprise. Glad you got it sorted, Enjoy.

[Brendan D25]

James, you have to be commended on a job well done. I have been following your posts and admire your tenacity and patience. I guess any overdrive questions in future will be referred to you. Cheers, Brendan.

[JohnS48plm]

James, Glad to hear of your success with the overdrive. I've been through several myself and the tests and measurements in the book do make a difference. I've got about 4000 miles on the one in my P-15 and it still shifts smooth. JohnS

[mackster]

Good news! actually Great news! no noise, faster pick up, and zero drop outs. . . I bet it feels nice to drive it around as you wanted all along! congrats for your well deserve fruits of your hard work. . .

[Don Coatney]

Are you shopping for an Airstream yet?

[Normspeed]

I'm glad all your hard work paid off. These are great units when working properly.

[BobT-47P15]

Congratulations on your success, James.

Amazing how such things as motor mounts can affect other things.

Now, enjoy!

[RobertKB]

Glad to hear that at last all is well. You are now officially the overdrive guru!

[Jim Shepard]

James,

You should consider driving over to Tim's on the 25th of April for the 2nd Annual Pilothouse BBQ. I'd like to see your OD setup. I've got a Fluid Drive 3-speed in my '50 truck that I'd like to mate to an OD.