Worst thing you can do to a transmission?

I have a couple contendors in the "automatic" category, based upon things my folks have done. Very bad with cars...

A) 1974 Chevy Caprice stuck in snow. In order to get it unstuck, they shifted into reverse, then floored it, stepped on the brake, put into drive, floored it...process repeated several times with increasing rapidity until *clunk* we were dead.

B)1985 Chevy Suburban. Never changed fluid or checked fluid level, in spite of some very rigorous use such as hauling heavy trailer up extremely steep Mexican mountains on really bad roads. One day it overheated and seized up due to it being extremely low on fluid. It started working again, sort of, when fluid was added, but died completely soon afterwards.

I also once had a friend who always put it into park before he was completely stopped..sometimes it made a groaning noise. Needless to say, the tranny eventually went on that one as well.

I also have some nasty stories involving friends who never checked or changed their oil, never checked their coolant, and/or completely ignored engine and temperature warning lights, but that would be off this topic. You could, however, have a topic called Horrifically Stupid Things People do to Cars.

Worst thing you can do to a transmission? That's easy: Buy it, if it's a Chrysler A604, a GM TH700R4, TH200R4 or THM250, a Ford AXOD, or a Borg-Warner BW35.

In your own car or a rental?

Then...make sure the video camera is filming this.

What I carry as *spare equipment,* is 1/2 the weight of just one of your butt cheeks.

If you really want to save on fuel bills, Lose some weight, tubby.

Lg

loan it to my ex-wife...that bitch would tear anything up!

Depends on the transmission. For some, neutral drops into reverse are instant death (or close to it). For others the weakest point may be something else (neutral drop into drive, running low on fluid, etc.)

The other two answers to this were good.

My contribution: Drive it when your engine is overheated. It'll usually cause the fluid to varnish the clutches and bands, causing the trans to start slipping, which of course generates more heat. Vicious cycle ending in trans failure.

-LMB

Oh yea! Another real bad thing is to add antifreeze to the fluid...

-LMB

It is possible somebody has done that? I guess anything is possible. I can't imagine why anybody would add anything other than transmission fluid to a transmission. Doesn't make sense. Either does this thread.

Since a transmission of the type that I am using cost upwards of $4,000, I try to treat the thing with a bit of respect and care. Goes for the rest of the vehicle as well. So far, I've not any any major problems with this car. Then again, after following a newsgroup on the WWW about *Taurus* problems...I've learned that some of the things I've encountered have simple solutions. Like my engine surging problem.

Solved that by going after the gunk built up around the throttle plate. I don't know what I would have been screwed out of had I brought it to a dealership, but it would be more than the $5 I paid for a can of throttle plate cleaner.

Lg

It's real easy for it to happen inadvertantly, as the vast majority of modern automatic transmissions have oil-to-water heat exchangers built into the bottom (or cold side) tank of the radiator. If the cooling system is neglected long enough, the tubes of the trans cooler can corrode and the engine and trans will start swapping fluids, and the trans usually loses.

nate

My taurus has a separate radiator for tranny fluid underneath the radiator for the engine coolant. Mine looks like one of those baseboard heating units with the fins on them. Thank G-d. One less problem to worry about.

The transmission cooler is so simple to get at on the Taurus, but like I said, I am LUCKY it is a separate device, as far as I can tell. Not part of the engine cooling equipment. Maybe this is unique to this particular vehicle, and most others have the arrangement you describe.

IIRC, my last Chevy Cavalier had both coolers combined IIRC, just like you say.

Lg

Why driving in 4H or 4L on non slippery road with part-time 4 wheel driver car is bad for transmission?

Lawrence beat me to it, and he's right. A degraded cooler tank can cause fluid exchange. The antifreeze will utterly destroy the friction materials inside the trans, so it'll require a rebuild, if you're lucky, replacement if not.

-LMB

What about the "stick shift effect" on an automatic?

I'm not so sure that they're all bad... you have to neglect your cooling system pretty badly to get that much corrosion. The nice thing about oil-to-water coolers is that they also offer a warming effect in the winter, helping to get everything up to temp. nice and quickly. I'm surprised they're not used for engine oil more often. In fact had I a car that had had the option of a water-cooled automatic, I'd be tempted to replace the radiator with the automatic version and use the trans cooler as an engine oil cooler. I've had at least three cars with oil-to-water engine oil coolers and they really help the oil warm up faster in winter while reducing the maximum oil temp, and have no moving parts unlike oil thermostats for add-on oil-to-air coolers.

nate

You don't have to worry about that if you switch to Synthetic. Not Synthetic *mix* but pure synthetic. My below zero engine starts are instantaneous. No *cranking* time, just boom, the engine is running.

That's what the thermostat is for. Your vehicle should run in the 195 to 200F range and your oil should not get much above that, since it is cooled by the water jacket in the engine block just like the rest of the engine parts.

I don't see how, if you have a functioning thermostat and half-decent radiator, how your oil temp needs an extra *cooler.* I doubt it ever gets above the boiling point of water.

Lg

That's not exactly what I'm talking about; I was more referring to the oil being up to *full* engine temp this indicating that the engine was fully warmed up.

The oil is generally the hottest fluid in the vehicle; on the last car that I had an oil temp gauge in (VW Scirocco) it would consistently run about 125C on the highway, until I installed the cooler (it'd been removed at some point) then it ran about 110-115C most of the time, which is pretty much ideal. The real advantage, as I said, was that the oil would get up over 100C much faster with the cooler than without.

I wouldn't want the oil to be running much *less* than the boiling point of water, as then it would load up with condensation and other nastiness that otherwise would boil/burn off.

see above... some cars are marginal in that respect, I've seen oil temps as high as 260F on a Corrado after being stuck in traffic. But the idea is to get it into its ideal range, i.e. just at or above 100C/212F and then don't let it get any hotter.

nate

1. Related, transfer case ... but I could just as easily post unrelated. Some might consider the transfer case as being a transmission component, just as some might consider that bolt on overdrive my Healey had as a transmission component.