Is there a minimum 700r4 temp?

[raunch]

My normal operating temperature holds steady at about 125 degrees. On a hot day, pulling my #2500 tent trailer up a pass, the temp will climb to 165 and I have never seen more than 180 degrees. I just saw in another thread a minimun operating temp of 160 degrees. So is 125 too low?

A little background...I installed an aftermarket tranny cooler that is about 11" square. The 700r4 has the lockup removed and the pump modified to compensate for no lock up. I don't know the details on that modification. The tranny is built up a little too.

Thanks.

[More Power]

The industry wants to see a routine minimum temperature of 140 degrees F in the transmission, which will keep moisture from forming/staying inside the transmission. I suppose there is some leeway though for the low side of temps...

Jim

[Robyn]

With the lockup removal mods made (they use a converter that has larger guts) the low temps are not going to kill the thing. Having the ability to get rid of the extra heat will be of more benefit.

If you like, fashion a "Winter front" for the tranny cooler and shut off some of the air flow to help raise the temp a little.

160F is lovely. When you get over 200F it starts taking its toll on things.

The oil breaks down faster and if you get to 250F or 300F the oil fries.

The high temps also take a greater toll on the little lip seals in the servos and such too.

125F is not bad at all really.

Try shutting off the airflow through half of the extra cooler and see if you can get the temps up to 150/160F under a load.

At cruising speed the tranny produces very little heat, its when you are working the thing and the converter is running a lot of oil through the stator and back into the turbine that the heat really starts to head north.

A 700R without a lockup will make more heat when in 4th. The OD will make things work a tad harder.

Depending on how the converter was built (How tight it is) The old RV converters that we used to put in Rv's and tow rigs were built to achieve a closer hydraulic lock than the stockers. This was accomplished by changing the blade angles on the turbine and the pump and what stator they used.

There are some pretty clever converter builders out there that have come up with some pretty cool stuff.

The stock converter on a 700R has the lockup clutch, this uses a fair amount of space up in the front of the converter, resulting in a loss of size in the pump and turbine.

Have fun, keep us posted.

Missy

[raunch]

Thanks all for the info. At least I know that the low temps aren't going to kill the thing. Currently I have a grill cover and It does help a little. If I drive it long enough around town, the tranny temps will climb to about 150. Going down the road the temps still hover around 125. I guess that is where it like to run. So come spring time when the grill cover comes off, I will experiment a little and fashion some sort of half-cover like Robyn mentioned and report back.

[raunch]

Just got back from a 2000 mile road trip pulling my tent trailer. Over snowy passes, through the hot desert, and back again. The tranny temps, with the grill cover removed, stayed around 150*running in OD. When the outside air was a bit a cooler, like the early mornings, the temps would stay around 125*. I did see 180* for a few minutes as a topped out on a mountain pass. All-in-all, it was just fine and I don't think I will need a wind screen to keep the temps at about the 140* area, at least when I am pulling a trailer.

[DmaxMaverick]

While 160°F is considered the optimal operating temp, 140-180° is an acceptable operating range. This is where the fluid and transmission is designed to perform best. Using synthetic fluid can expand that range to some degree, in both directions. Too cool and the fluid viscosity may be too high, and it may allow acid formation and moisture collection. Too hot can damage the fluid, seals and friction surfaces, and cause other issues due to thermal expansion and reduced fluid viscosity.

[raunch]

Sold the tent trailer and got a hard sided travel trailer. Only weighs #3500 dry, and the tranny operates just a bit above 150* pulling the trailer.

There are other issues though...engine runs hotter, can only go about 55, it's loud. But that's another post. Maybe in the classifieds.