Another cooler or a fan?

[dyeager535]

If you run your t-fluid through your engine rad, what can you expect but 210?

Whatever the *outlet* temp of the radiator is. Remember, stock trans cooler is in the "coldest" part of the radiator and not regulated by anything other than the engines thermostat.

Ideally coolant entering the engine would be less than 195*, (or whatever t-stat rated temp is) and if the thermostat just opened, even less.

 

[4xcrazy]

This is what i was thinkin too, yeah, the trans fluid gets "pre-cooled" by the radiator water, then you run it through the aux cooler for additional cooling,,,hmmm,,,

 

[hawkeye649]

Funny I always thought of it as, the tranny fluid gets heated up when it's cooler than the radiator. And thinking it gets warmed up by the engine to operating temperature faster is a joke, it only takes about 10 seconds in drive with the brake on before the the output line is warm and the t-stat hasn't even thought of opening.
Like I said, I don't have a gauge on my tranny. But I do know that my fluid lines whenever I've felt them are always cooler then when they ran through the radiator. I did this because of an old leaky radiator I have since replaced, but I am glad I did so.
This is always a touchy subject though, a good one for trolls. Some say there is a proper operating temp for trannys, some say colder is better. I go with the latter, because I notice 0 difference when it's dead cold or at operating temp. Doesn't slip in the winter, and doesn't burn up in the summer.
I've gotten my info and oppinions from a good friend who owns a tranny shop. He does allot of work and warranties his GM trannies for longer than GM does, and I have my rig setup with exactly the same parts, placement, etc. that he would do on one of his rebuilds.
So I guess the real trueism of this post, that all would agree with is this:
It don't matter what you do, it's an auto and will grind it's self into little bits no matter what you do.

 

[surpip]

what t-stat do you have in your tranny?
for that year i believe stock is 195, i took it out and put in a 175, the motor gets hot enough to go out of closed loop, and it runs allot cooler.

 

[hawkeye649]

Great. Leaky radiator, a "good friend who does transmissions" (and don't we all have one of these...), and no gauge to measure temperature. That's a great way to try and make a contribution to a tech post. Way to go. Just fabulous. And all of that from a place where the ambient temp never goes above 65F.

Wow, you just added a lot. Thanks for all that info.

 

[hawkeye649]

what t-stat do you have in your tranny?
for that year i believe stock is 195, i took it out and put in a 175, the motor gets hot enough to go out of closed loop, and it runs allot cooler.

I have a 195 in there, changed it just so I would know how old it was once I got the truck. Engines have a temp where they run best, and I say that GM knows that better than I do.
The lines used to hurt to touch, never have that problem now. Tranny fluid used to come out burnt, every time. Now it looks every bit like what's going in, though it feels different.

 

[Cricket]

I say move the cooler out back, maybe with a small fan. Or maybe James could blow on it while he hitches a ride with you.

Very funny John.

I think I'll just resign myself to being the "shovel boy".

 

[K5TRLBLZR]

My .02 is just run the tranny cooler with a fan and a manual switch. Disconnect it from the radiator. This setup has worked great for me for years on the con or just sitting in traffic in the summer. LOL

 

[Jonny-K5]

i dont know why, but my temps rise when im in 4low. it defies logic, but it'll rise to over 180 in low, and when i put in back into hi range, it'll drop 10-15*. this is in an 89 with a bowtie OD 700, 4.56 and 35"tires. sensor in the pan.

i have a tranny fan too, i think its a factory unit off another truck, came with my truck in a box of spare parts. havent noticed a bit of difference with it on or offroad,except for my voltmeter dropping.

i think i have the stock tow package cooler.it is a stacked plate design, but maybe its getting old and not cooling properly. a new cooler might respond better to a fan.

i personally dont think the radiator does anything to cool the tranny fluid. if you have a 195* stat, i'd say at most the coolant temp coming out of the radiator is 170. if you trying to keep your tranny below 150, hows it gonna help? only reason i can see is to keep the tranny below 200*, or to warm the fluid up in winter.

i think a good setup for a 700 in warm weather is to run it thru the radiator, then thru two big coolers with a fan on the last one.

 

[hawkeye649]

i dont know why, but my temps rise when im in 4low. it defies logic, but it'll rise to over 180 in low, and when i put in back into hi range, it'll drop 10-15*. this is in an 89 with a bowtie OD 700, 4.56 and 35"tires. sensor in the pan.

i have a tranny fan too, i think its a factory unit off another truck, came with my truck in a box of spare parts. havent noticed a bit of difference with it on or offroad,except for my voltmeter dropping.

i think i have the stock tow package cooler.it is a stacked plate design, but maybe its getting old and not cooling properly. a new cooler might respond better to a fan.

i personally dont think the radiator does anything to cool the tranny fluid. if you have a 195* stat, i'd say at most the coolant temp coming out of the radiator is 170. if you trying to keep your tranny below 150, hows it gonna help? only reason i can see is to keep the tranny below 200*, or to warm the fluid up in winter.

i think a good setup for a 700 in warm weather is to run it thru the radiator, then thru two big coolers with a fan on the last one.

Your transmission warms up rediculously faster than your engine could ever concieve of doing, fluid wise at least.

Two big coolers in series would produce the absolute coolest condition sure, but I would run them in parallel if I had two. Again, my "tranny friend" suggested this and I like his reason. If one becomes clogged/less effecient, the other one will still do the job. He has also said that parallel coolers, that aren't piled ontop of each other but side-side (for max cool air on them) comes to a comperable coolness to series. But, if one is getting clogged than the other probably will too. I'd still have to think on it if I was going for a dual-cooler setup, but I'd probably go with parallel - redundancy is always a good thing in my eyes.
But what do I know, I've never been in weather above 65*F....

 

[Jonny-K5]

Your transmission warms up rediculously faster than your engine could ever concieve of doing, fluid wise at least.

you sure about that? you can warm an engine up by just idling for a couple minutes, or driving a couple city blocks. assuming you have a thermostat. takes alot longer than that to get my tranny fluid warmed up to 150*

 

[surpip]

Engines have a temp where they run best, and I say that GM knows that better than I do.

i disagree, gm made the engine run hotter, to get the cat up to temp faster, and thereby reduce emissions. The engine will actually be more efficient at a lower temperature, to a point.

Your transmission warms up ridiculously faster than your engine could ever conceive of doing, fluid wise at least.

again i disagree, my engine will reach operating temp. alt faster than my tranny will, in all conditions.

 

[dyeager535]

GM has used the same thermostat for a lot longer than cats have been in use.
Clearances and fluids can only be spec'd when you know what kind of heat you will be dealing with.

 

[hawkeye649]

If you grab your transmission lines after running the truck in drive with the brake on for 10 seconds they will already be warm. Feel your radiator hoses and they wont be. That's my observation.