Alright, since I am still learning a bunch of stuff (everything)...let's see what this turns up.

I have a mild LT1 (stock heads, hot cam, bolt-ons) running a 3200 yank, mildly-built 4L60 (trans-go, a few harder parrts), a huge X wide cooler in front of the AC condenser, and a temp gauge plumbed into the test port (upper LH side of the case). I do not use the factory cooler which serves to raise tranny temps to coolant temp. My stall does that just fine as it is.

Let me clarify.....1/2 my daily drive is at speeds below 45mph and accounts for about 15 or so miles. During this time I encounter deer, ducks, geese, many curves, hills (we live in the sticks)....you get the idea...there is a lot of speed variance. The tranny warms up just fine, but rarely...ever..even on hot days goes over 150deg. If I pound the snot out of it..ie point and shoot WOT from corner to corner the temps will rise to about 170deg and that's generally it. At the track...the temps never exceed 150deg.

All the theory and opinions I have heard suggest over 200 is death. Also, if you can keep it under 200 that's great. So, what is the lower limit...?

BTW... I am on my 10th.....10th rebuild (last one was only a spot on the band and 1 solenoid flat died). Did I mention I also have a external filter plumbed in series after my tranny cooler and the filter and one quart of fluid is changed with every oil change (you understand I go overboard to avoid failures...one was a pan magnet that broke apart and gummed up my valve body).

So..what is the ideal temp....what is too high and what is too low...?

School me. It won't be long till I try to find my own 700R4 core to build a beastie for my car and see if I can screw things up more than they already are. I'd rather not have electronics (as my current 4l60e has) that can simply cause more issues that are difficult to trace after the fact.

 

Not sure what your asking. But your temp. may accually be a bit low, so you should have no temp. related failures. I believe the standard is sustained temp in the 200 to 225 range, should not be determental.

 

150 - 180 degrees is great, the fluid should last for a long time at these temps.

 

thanks for the replies. I change a quart with every filter change (external spin-on filter).

Great...I was hoping there wasn't going to be a problem from running too cool.

 

200F is not the temp of death for engines nor automatic transmissions. 150F might be.

Low trans temps tend to promote sludge, and probably bad lubrication of sliding things like clutch disks (during engagement). You have noticed that your engine gets to 180+ operating temp well before your trans, so if you hammer it when engine is up to temp, but not trans, it shortens trans life a lot.

One of the reasons OEM coolers are in the radiator is to control the trans temp into the designed operating range. In slow mild driving or in cool or cold temps, the "cooler" is really a "warmer". Bypassing it, especially thru a "huge X wide cooler" is, IMO, the wrong way to go. 10 rebuilds is 9 too many. You may be part of the problem.

I would plumb the oil back into the OEM cooler and if I wanted an additional cooler, I'd put it between the engine and the radiator cooler so that the trans always received coolant temp oil, not cold oil. If your TC is generating lots of heat, the aux cooler will get rid of most of it, and the OEM cooler will then either heat or cool the trans oil as necessary.

IMO, external filter and oil change may be doing more harm than good. The trans oil system is closed. There aren't combustion contaminents like in engine oil requiring changes regularly. Only if the clutches or bands are slipping badly should you see any oil contamination. Of course, if it never gets hot, any condensation just stays in the oil.

You asked for opinions.

 

Obviously you do not want water in your oil. Every night water condenses onto the interior surfaces of the motor, trans, and differential. You need to get the oil hot enough to evaporate off this water. If you are going to use an over size cooler get an oil bypass/thermastat.

 

well nutz.

I can replumb the system easily enough to bring temps up.

On the last go through....a solenoid failed (it seemed like 2 and 4 were gone so I assumed the worst). The shop said the frictions all looked like new (this is with about 15k on them) and the bqad had one spot where it was worn some. To me...it all looked like it was just assembled. I admit in the winter I worry because the tranny temps never rise over 130.

This crap is getting old. I get so many conflicting pieces of advice. I.E.....my tranny shop said that 150 was fine and that I must keep it below 225.

I will put the aux cooler in series after the factory cooler as when I had it in this configuration, temps hovered in the 180deg area which I am supposing, should be ideal.

What about pressure drop across the factory cooler, the aux cooler and then the filter (which I won't remove)....? Is the return pressure an issue to be concerned with...?

The aftermarket filter is a 'feel good' item for me. I've lost two trannys from debris that was not caused by something I did wrong. One time the pan magnet broke apart (yeah, doesn't that suck) and another a seal decided to disintegrate and plug things up. Both extensive rebuilds could have been reduced somewhat had an effective filtration system been in place. Any contaminants that get lodged in the coolers (which I clean thoroughly after every rebuild) won't get past the filter.

Maybe my desire to have a tranny survive has also lended itself to causing me even more grief. I think my next turn is a TH350.