Reverse on a Cruise O Matic

[123finboy]

My car has to warm up for a good 15 minutes before it will engage reverse gear. Once it's running and on the road, reverse works great. But when cold, reverse takes a long time to engage. What gives?

[Finster]

I had this exact problem with my Cruise O Matic. It started with this and eventually got worse after a while. Eventually I had the transmission rebuilt. I knew someone near me who is 80 yrs old who sold his transmission shop and retired but still did old transmissions on the side. A lot of industry knowledge who worked on these when they were new. I watched him take the transmission apart and go through it so I will tell you what he told me. Impressive how quick he got it out of the car and how quick he got it apart - before you know it we were ordering the parts. Half hour at most.

With mine the seals were shot - They were rock hard and brittle. As you let the engine warm up it caused the seals to soften/expand and actually seal what they were supposed to. Due to this issue the rear band and servo was becoming worn and these issues contributed to a small crack in the case - which is a normal complication with these transmissions. When the seals expand then the transmission is able to pressurize and the pump then works properly etc.

He mentioned a temporary fix was to put a little DOT 3 brake fluid in with the transmission fluid - he said this was an old trick that helped to lubricate things and soften the gaskets but it is a band-aid.
Hope this helps - good luck!

[123finboy]

Thanks, this explains a lot. I've heard of people using Dot3 to lubricate the vacuum windshield wipers too. I know a rebuild is my future, I'm just trying to nurse it along for now.