Limp mode is pretty much when the PCM detects something that'* REALLY harmfull to the vehicle, that could end it'* life or severly damage the part in check, the PCM defaults back to what I call a "Gimp" program, or "Limp" mode.

Pretty much, it takes and makes the car just driveable enough without doing too much further damage to anything just drivable enough to get to a service shop or dealer.

As for the trans temps, they're still gonna get to optimum I realized last evening if you DO NOT by pass the radiatior tank cooler. 185-210* coolant passing around it will help it get warm and stay in that safety zone. At least that would be my theory.

Would you be able to tell that the PCM is in "Limp mode"?

Nate, are you now considering leaving the preheat part of the radiator connected? Going by what Willwren has said on this, I was planning on bypassing the preheater. Hence BillBoost'* concern.

You should notice Gimp mode pretty quickly.

That'* curious then because my PCM never went into gimp mode even though my transmission was about to die. One minute, I was travelling along. The next I stop at an intersection and never get going again.

Trust me.....You'll know "Gimp" mode if your car get'* that bad.

Pretty much you can't leave second gear, no first gear, or won't shift out of first until you redline the **** out of it to force second, and you prolly won't go much faster than 30-40 MPH depending on how these cars were programed.

That'* just a lil bit of what my 94 Chevy 1500 did when it had hit limp mode a few times.

As for the preheater, yes I'm considering leaving it in line. The way I look at it is, this fan is gonna be more than enough to cool the trans while stopped, along with moving down the interstate with the fan off.

The fact too, that we both live in pretty fridgid winter climates, that we will prolly need that preheater to get things moving, and possibly may have to unplug the fan so the op heat will stay in while driving, or stopped....It all really varies depending on situations.

I also haven't really verified wether or not that fan on there is automatic or we need to install a switch. If it'* automatic, then chances are we just need a resistor to change the temp that the fan engages, switched, you have total control of "How Cool" your trans will be.

I know for a fact the B and N model I bought switches automatically at 175. Its thermostically controlled. There'* basically three connections on it: Fan TRans oil in, trans oil out.

3 Electrical connections, or just connections in general?

And since your fan is auto started at 175*....then you wouldn't have to worry anything about that. From the sounds of it, I would leave the stock preheater in the line....or if you want, install the cooler, and in the winter time bypass the preheater and see how it does?

Don, I believe that unit is FAN ONLY. At 170. Not a good idea.