I want to run something by you guys before I trade in my R51.

I have a 2006, bypassed trans, I maintain all my own fluids religiously.

I'm driving cross US, I've done 10k miles, much of it in mountains, towing a 5400lb gross trailer.

About 5x in the last 2+ months, all while going uphill, the 4WD light comes on, Service Engine Soon comes on, and the car will not drive. Engine is running, rpm's go up, but truck will not drive.

It seems once it cools it drives with no problem, 4wd light immediately goes off and Service light goes off after a new tank of gas.

When this happens the trans fluid smells hot/perhaps smoky and actually steams. Color is nice and clear pink after 2 4 gallon flushes with Mobil1 in the last 3 months.

Am I answering my own question lol? Is this a strange way for the truck to tell me the trans is overheating? A sensor issue? Any thoughts?

I have plans to buy an F250 but love my r51!

Help!

Has anyone dealt with this 4wd light and loss of power?

You need to retrieve the stored trouble codes. A lot of times, a faulty cam position sensor or crank position sensor will cause this. Most parts stores will pull the ECM trouble codes for no charge.

I was having a similar issue. Pulling ANY trailer. Aamco replaced the valve body and (since I have a new radiator) restored the trans cooler lines thru it and an external front-mounted cooler. Last week pulled my small pop-up Coleman Taos camper into the N. Georgia mountains with no problems. Take it out of O/D when going up hill. Nissan wanted to replace the transmission because it was "overheating".

Smj, you're saying this loss of power created a fault code that can help decipher the problem?

Titus_RacerX wrote:I was having a similar issue. Pulling ANY trailer. Aamco replaced the valve body and (since I have a new radiator) restored the trans cooler lines thru it and an external front-mounted cooler. Last week pulled my small pop-up Coleman Taos camper into the N. Georgia mountains with no problems. Take it out of O/D when going up hill. Nissan wanted to replace the transmission because it was "overheating".

Titus, when you say you were having a similar problem did the four wheel drive light come on and you lose power?

What is the valve body and how do you think that was causing your issue?

My major concern is if this truck is simply overloaded I don't want to dump a bunch of money in to it.

Thanks!

I just want to add the motor temp is always normal when this happens.

There should be at least a stored code you can read, that will help with the diagnosis.

Tonight I drover 120 miles flat, no issue.

I came to the first hill, literally 1/10 of a mile up the hill, 4wd light and power loss.

I'm going to have to trade it in. Where I'm coming from in Yosemite, I won't make it to a shop or dealership to get diagnostics run.

I'm literally on the side of a CA highway looking for the nearest dealership to trade it in.

Sucks cause it did 7000 miles through Yellowstone and Badlands with no problem