Twin Ultramatic Lifespan.

Posted by Redhexagon On 2022/10/11 3:30:05

My February of 1955 TU has 65,000 original miles. It's never been rebuilt. I know the answer to this question is completely subjective and dependent on so many things, but...how much longer does it likely have before it takes a dump and leaves me stranded way out in BFE?

I fully serviced it with a complete drain and refill of Type F (getting the bell housing off to drain the converter SUCKS!!!), adjusted the bands, adjusted the selector linkage, and adjusted the throttle linkage. There was more metallic gray sludge in the pan than I am used to seeing on 1970's automatics, but maybe that is normal for TU's, and I do not know the last time it was changed.

It shifts perfectly. No flare or hang-up between low and high and it's smooth. The converter lockup to direct drive happens very smoothly. There is no "groan" or "moo", just a smooth slide into direct drive. I actually wish it was less of a slide and more of a firm shift to save wear on the clutch. I've developed the habit of lifting off the throttle at around 30 mph to make it lock quickly and not under load to save wear.

I moved the adjusting link on the throttle rod rearwards about 3/8" to make the transmission think the throttle way farther open. I thought this would raise the shift points and firm them up, reducing wear on the transmission. It's a trick the Mopar guys use on Torque Flites. It did raise and firm-up the shifts at first, but then one day it suddenly got really bad flare between shifts and slipping in all drive ranges. It scared the living daylights out of me. I thought my transmission was dying. Talk about being white as a ghost! Fortunately, I was barely outside my driveway. I adjusted the linkage back to factory setting and it's been 100% fine ever since. I don't know why it would do that. It goes against logic. Maybe the selector was between ranges or the governor stuck. I don't know, but I sure as heck am never doing that again! That was scary as #^@$$.

Anyway, so...do Twin Ultramatics usually make it to 100,000 miles before needing rebuilt?

Thanks.