Fun day with the transmission

[Renthal]

I got a 2001 QX4 a month ago, runs great
I was towing my loaded 17 foot boat up a big hill today and everything was running great until i looked in the rear view mirror and saw smoke billowing out of my truck!

I doubt my boat and trailer is over 3000 pounds.. its just your run of the mill lake boat with an 80 hp on the back
I pulled over, transmission fluid was dripping on the ground, and smoke was coming out under the hood..

I let it sit for an hour, my buddy came and got my boat, The transmission oil level was ok, and my truck drove home without issue.
I'm guessing I overheated the transmission... is there any damage that I could have done? it runs and drives fine.
Should i do a flush and replace the filter?

Thanks

[Towncivilian]

The fluid overheated and overflowed out of the vent tube. Since the fluid was at such a high temperature for a long time, the fluid's life was probably shortened significantly. You should do a complete fluid exchange. There is no need to replace the transmission pickup screen since it doesn't filter very finely, it should not be clogged.

Welcome to NICO!

[Chuck Tribolet]

It sounds like you have an automatic. The automatic 2001 Pathfinder was rated at 5000 pounds tow capacity. The stick was 3500 pounds,
and I'd guess the QX4s would be the same.

I have a 17 foot Boston Whaler with a 90HP carbureted Evinrude, and boat, motor, and trailer are about 2000 pounds.

How much did you have in the truck? The max towing capacities are with driver only.

Have you towed the boat before with this vehicle?

Does the QX4 have a recommendation to turn off the overdrive gear on the transmission?

I think there's an underlying cause to be sought.

[Renthal]

thanks for the responses guys.. It is an auto.
There was maybe 2-300 pounds of gear in the truck and myself.
I have towed the boat just around town with this QX4 with no problems, other then a saggy rear suspension
The mountain i was driving up is pretty notorious for wrecking cars... a good 15 minute climb at 100 km/h

I found this service bulletin from infiniti http://www.infinitig37.com/TSB/ITB00-042a.pdf
talking about how the oil cooler in the rad must be inspected and cleaned with transmission service?

I was also looking at this oil cooler B&M 70264 and should it bolt right in by the rad?
Cheers

[Towncivilian]

Yea, the B&M 70264 is good. I run a slightly lower rated model, the 70268, and it fits fine. The thicker 70264 will fit fine too. I can provide photos of my setup if you want.

The oil cooler doesn't need to be cleaned, but it wouldn't hurt.

The fluid exchange procedure can be found in the general info thread linked in my signature.