View Full Version : No 2-3 shift when cold

03-28-2014, 10:05 PM
My 62 has to be driven maybe 5 miles before it will upshift to 3rd. It has 18 inches of vacuum at modulator and modulator will hold vacuum. Kickdown linkage also appears to be ok. Anyone with thoughts or experience?

03-29-2014, 01:15 AM
All oil absorbs water. Usually, we heat the engine hot enough and frequently enough for the water to vaporize and go out the vent.

So, oil with water will make your clutches and bands operate differently, assuming they are properly adjusted.

Different types of trans oil will also make your clutches and bands work differently. If you stick to the recommended trans fluid type in your owner's manual or shop manual, the trans should operate correctly.

Keep your trans fluid at the correct level at all times. Nothing will kill a trans faster than one with low oil. Band adjustment can be done at the same time as a transmission oil and filter change buy a good transmission shop. Call around and ask if they have experience with your transmission. Most trans shops don't. Cruise-O-Matic and C-6 transmissions were commonplace back in the day. Most modern mechanics see one in a blue moon. - Dave

03-29-2014, 11:07 PM
Thanks for the input Dave. I agree that quality,quantity,and type of fluid is important, however in the 60's trans fluid was still being produced with whale oil. Don't think I can get my hands on it anymore. Modern fluid will have to do but what type would you recommend?

03-30-2014, 11:24 AM
I always use Type F fluid since that was the replacement for the Type A that was originally used.


03-31-2014, 06:04 AM
There were several reasons for not using whale oil (besides protests from the whales). Since the 1970s engines run hotter, and whale oil breaks down with excessive heat. Synthetics are taking over because they do well with hotter environments. (Mercon V has been in vogue since 2006.)

Our classic engines still run cooler and the transmissions do well with Type F, as John mentioned. There is no shortage around Detroit. - Dave