Questions on a 1954 4-speed, and a ’36 temperature gauge

Question:

The Hydra-Matic transmission on my 1954 Pontiac Star Chief will not shift into fourth gear. I have played with the linkage quite a bit, including manually moving the kick-down lever while driving by pulling on it with a wire. I’m afraid the problem may be internal but I don’t know what to look for inside the pan. Is there a particular valve that may be faulty?

I am also trying to restore a temperature gauge for a 1936 Ford. This gauge has a copper tube coming from a probe in the engine block that terminates in a glass tube on the dash. The glass tube appears to have had a red liquid in it, which has long since disappeared. Is there a way to replace this liquid?

Answer:

Most people are quite surprised to learn that early Hydra-Matic automatic transmissions used in Pontiacs, Cadillacs, and various other cars were 4-speeds. The inability of your transmission to shift into fourth may be due to a number of different maladies, but a problem with the linkage or kick-down is probably not related to what’s wrong.

Before taking anything apart, check the positioning of the parking brake bracket. This bracket should be flat against the transmission case and if it’s not completely flat in transmissions produced after 1951 it may prevent up-shift into fourth gear.

If the park brake bracket is correctly positioned then your transmission’s problem is almost certainly internal. Remove the valve body and inspect the passages machined into the case beneath the valve body. If the exhaust passage is blocked or restricted, the governor pressure will be trapped behind the 3-to-4 shift valve and governor plug. If the passages are free then you should evaluate the condition of the governor. If the governor plungers are sticking or if the governor’s rings and ring lands are sufficiently worn, the transmission won’t shift into fourth gear. Shift action is accomplished by hydraulic pressure and if the oil delivery sleeve is worn or if the feed and delivery pipes don’t fit correctly you won’t get a 3-4 up-shift. The problem may be in the control valve assembly. Make sure the 3-4 shift valve is moving freely. Also, look for a faulty governor plug, regulator plug, sticking TV regulator valve or TV valves, all of which are involved with the 3-4 up-shift.

If you are going to attempt to disassemble the transmission yourself in order to evaluate internal parts you should invest in a Hydra-Matic service manual.

As for your second question, there are reproduction temperature gauge assemblies available for your 1936 Ford but my understanding is that they are made in a country that has a reputation for producing low-quality goods and the gauges are unreliable and prone to failure. You are, therefore, better off fixing the gauge that you have or seeking out a good used one. A fellow named Ray Martin (802-8626374) can restore your broken gauge. It is possible to repair it yourself and you can find detailed instructions on how to do that on Todd Fitch’s 1933 Plymouth Web site: http://www.ply33.com/Repair/tempgauge.