HunterKiller89

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I guess this is directed to Maven, as he's probably the only one to know for sure. But what temps are considered normal operating temps for a 4t45e, what is considered on the cool side (helpful/longer lasting tranny), and what is considered too cold to be considered a benefit?

Maven

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Normal is approx 180-205F, I'd say that 170-180 is the cool side, extended operation below 165 or so will give no benefit, and will likely simply cost you fuel.

celicacobalt

i have a trans temp gauge and after operating for long periods of time the highest ive ever seen it go is 185 degrees F. Note that im turbocharged and i'm running an extra trans cooler.

HunterKiller89

iTrader: (1)

^^ im in the same boat. it takes forever to heat up all the oil in our trannys (what...12 qts?), and in a typical 15 minute drive to work/school/friends house it usually reaches like 130-140 by the time i turn it off. I have never seen over 180* either, and wanted to make sure im not hurting the tranny

so maven, is it bad for the transmission to operate at such low emperatures? or does it have no effect on longevity and merely affects performance? Obviously engines are made to operate at 180*, and you increase the amount of wear and tear if coolant/oil temperatures are below this number. I just wanted to see if the transmission is the same thing

Maven

iTrader: (1)

All lubricated parts are essentially intended to operate at a certain temperature for maximum life expectancy. the auto transmission is no different. If your asking if 130ish degree temps are going to shorten its life......well the blunt answer is "yes" but its not as bad as you might think, obviously it would be better for the temps to get higher so the fluid reaches the proper viscocity and has enough heat to evaporate out any water vapor that accumulates in it. This isnt something new though, this is exactly why youve always heard that "short trips" are bad for your car. But as we all know, there are plenty of cars out there that are many years old, have in excess of 100k miles and have probably never been on a trip in excess of 10-15 miles on any kind of regular basis.

If you dont routinely go on longer(or sustained higher speed) trips and you are truly concerned about taking the best care of your car, I'd say just remove your trans cooler and all will be well. The factory trans "cooler" is small and oil-water based for a reason(cost obviously) but it does something an oil-air cooler(like the aftermarket ones) cant do......it actually HEATS UP the atf, it uses engine coolant to help bring atf up to temp quiclkly and then to help keep the temp stable.

RedBaseBolt

One other thing you might consider is using Royal Purple tranny fluid.

It's most likely the best you can get and I would bet it would help extend the life of your tranny.

Even for those 15 minutes or less trips.

Your tranny lives it's life a short trip at a time, and for those 15 minutes or less, it's free. :P

Maven

iTrader: (1)

Dexron VI is good stuff, its hard to get anything better, Redline makes D6 which I am gonna try one of these days once I decide to put it in.(ive got a 5spd with DexronVI) Royal purple doesnt even make anything they consider an equivalent for DexronVI, unless youve got an 05-06 auto, Id avoid RP ATF

Zooomer

iTrader: (1)

Transmission efficiency declines at temperatures below 150 deg. That's what we confirmed in street dyno and chassis dyno testing. As Maven stated, there are other benefits to having a trans warm up.

We are working on a transmission Tstat to allow the trans to reach temperature quicker in the colder months but with so many projects going on, I can't say if we'll ever have it done...

Maven

iTrader: (1)

I believe there are already commercially available thermostatically controlled coolers on the market, is your project a direct bolt on for the 4T45/4T65 or is it a variation of the current products?(IE just a thermostat with no cooler)

celicacobalt

would a cold tranny cause misfires at all. seems to happen more when the trans is in its colder temps.

HunterKiller89

iTrader: (1)

it shouldnt. al it should do is have less power output, especially if the power demand is fairly low. tranny temp wouldnt affect anything inside the combustion chamber, so it shouldnt affect misfires. Is there maybe a correlation between your engine temp and your misfires?

celicacobalt

yeah i can barely get on my engine above 2000 rpms without it hiccupping until 180 degrees. Even then depending on what i dont know if i punch the car it will sometimes go like a champ and other times misfire and fall on its face.

HunterKiller89

iTrader: (1)

you have a AFR gauge right? everything look fine there? any stored codes other than the random misfire one? whats your spark plug gap at? do you know which cylinders are misfiring?

celicacobalt

I have no a/f gauge. When it was tuned the ratios were all good but that was in the hot summer. now i may be running too lean with the colder air. I dont have a way to get to my codes. just the flashing cel comes up sometimes then goes away. My gap is at 0.040 same as when it was tuned. I dont know which cylinders are doing it.

HunterKiller89

iTrader: (1)

re-gap to .037 is really all i can suggest with the limited knowledge. You'll need a scanner or something like that to get more info. Really tho, .040 gap is probably where you want to start since its the easiest thing to adjust

celicacobalt

im just thinking its my fuel maps. it didnt act like this in the warmer temps when the oxygen was less dense. I just dont have the cash to have a better tuner tune it out for me right now. in the future i hope to.

HunterKiller89

iTrader: (1)

do the plugs then. it cant hurt...its free, and....yea. thats about it

DrSpok

my Autometer gauge must be incorrect , always says 210-230 even with a new rebuild HHR SS

Sharkey

iTrader: (1)

wow thread from the dead, over 9 years old lol.

the temp will greatly vary depending on where the sensor is. the sump is a good place to have a sensor. for ease of install a lot of people put them in a pressure port, and this is ok on some transmission, but on others this can read incorrectly as that port doesnt see any fluid flow. putting it in the cooler line going to the cooler can read hotter than the sump as its fluid coming straight out of the converter, the hottest point of the trans.