Replies to post #1604 on Cars, etc. (GEARHEAD)

[Phil(Hot Rod Chevy)]

k²,

I know you didn't ask me, but whatever, I didn't think you would mind.

I always heard that you should never change the ATF in Fords, but I don't know why.

I had a MOPAR once that would not move in any gear but reverse. Had the shop change the ATF and filter and it ran fine until I got a new car. (Company car, I always do most of my own work on mine)

Seems to me 15 years is too long to go without changing it though.

I would smell the fluid on the dipstick. If it smells burnt at all, I would change the fluid and the filter.

BTW, what made you ask?

I am one that doesn't like to screw with things unless they are broken, but I also believe in routine maintenance.

I kind of walk a fine line since I have so many cars on the road.

Have fun,
Phil

[OldAIMGuy]

Hi K², I'm in Phil's court here. I don't change auto tranny fluid often, but always do so in the first 30,000 miles. After that we've usually purged the system of any little nasties that were left over from the mfg process. I always have the tranny filter changed at the same time.

There was a time when transmission fluids changed significantly in formulation. It had to do with removing whale oil from the mix. When the change was made, the auto mfgs had a lot of trans. failures for a while. At that time people quit having their trans fluid changed because the "new" stuff didn't have the same lubricity because of the lack of whale oil. Their "old oil" was, in fact, better. Your friend's opinion may date to that period of time. (I think it was the '70s or maybe as late as the early '80s)

An oil collected from the Jojoba seed was found to work well as a substitute and was included in the trans. fluid formulations for a while. I'm not sure it was cost effective and whether it's still used. Later on other additions were made which took care of the problems.

As Phil mentioned, sometimes a fluid and filter change (along with some of the tranny fluid helpers) will take a sick transmission and make it shift fine. Here in Wisconsin we have rather larger temp variations between winter and summer. Winters will many times make auto transmission shifting problems worse. A friend of mine was facing a $1500 trans rebuild/replacement but fluid and filter change along with a bottle of some trans helper fluid took care of the problem. He drove the car for at least three more years with no problems. The car was sold to a youngster who continued to drive it until he crashed the car. (he was okay, but the car was totaled).

Another aspect of fluid changing has to do with "duty" of the vehicle. I'd think that stop & go city driving would be particularly hard on fluids. Also trailering heavy payloads can fry fluid if you don't have an aux. trans. cooler. Tranny coolers are cheap insurance for people who pull boats, cars, etc. behind their vehicles. Still a periodic fluid change makes sense.

Phil mentioned smelling the fluid. Its true that both color and smell can be indicators of overheated fluid. Many fluids turn a reddish brown when they've been cooked and will have a burnt smell.

There's now several "synthetic" fluids available. I don't know much about them, but have heard that they seem to do well.

That's about it from here!

Best regards, Tom