[chris196]

I have a 2010 CC SE 4x4 automatic transmission.
I was pulling my boat this morning and the transmission wouldn't shift to the next gear. I think I was in 2nd and it wouldn't go to third.
Here's the details. Pulling a ski nautique which is about a 4000# load. Entering a freeway with an uphill entrance ramp. Gave it the gas pretty good, but not floored. I was probably about 35-40mph and the rpms got up to over 4k and it wouldn't up shift. I backed off the accellerator then applied more lightly and it shifted. After that everything was fine.
This is the second time it's happened. It's happened before at the exact same spot. Some combination of the load, the grade, the speed is making the transmission not want to shift.

It was a strange morning. The boat started fine, then ready to take first ski run and wouldn't restart. Had to swim it back to the ramp. Put the trailer in deeper than normal because of no engine to push up on the trailer. Tried to pull out in 4wd Hi and slipped back into the water some more. That was a little scary. Put it in 4wd Lo and pulled out fine. Sure glad I got the 4wd and that's exactly why I did.
Then on the way home, once on the freeway a bird misjudged where he was going and glanced off my hood and bent my antenna.
After that, got home fine, but didn't get to ski.

 

[rcr_kx250f]

the computer is sensing the extra load and is holding each gear longer so the clutches don't get smoked. if you floor it the truck won't shift until red line. Also, take it out of over drive until you get on the freeway. increases oil flow and pressure for towing.

bad luck on the boat, has it been sitting all winter? might be a bad fuel filter.

 

[AndysLog]

his was better i had a **** explanation.

 

[chris196]

the computer is sensing the extra load and is holding each gear longer so the clutches don't get smoked. if you floor it the truck won't shift until red line. Also, take it out of over drive until you get on the freeway. increases oil flow and pressure for towing.

bad luck on the boat, has it been sitting all winter? might be a bad fuel filter.

I didn't have it floored, but maybe it thought I did. I think that's a decent explanation because once I backed off and applied throttle more slowly, it shifted.

No, the boat has been run a number of times already. This was our normal tuesday morning ski session. I'm pretty sure it's a fuel starvation issue.

 

[tholmes]

That would still be a fuel filter potentially. What year nautique? Does it have the 351? Thread jacks rule...

 

[chris196]

That would still be a fuel filter potentially. What year nautique? Does it have the 351? Thread jacks rule...

It's a 1998 with a GT-40 engine, so yes a 351W.
Yes, it could be the fuel filter, but that fuel delivery system is actually complex for that engine with a high and low pressure fuel pump and the fuel cell designed to stop vapor lock. Lots of potential problems.
It's a very reliable system, but when it goes out, takes some time to diagnose.

 

[dubie2003]

The VQ40 was derived from the VQ35 in the 350z. Both motors love to rev so let it. Turning OD off when towing is a must thou since it will help prolong the transmissions life (higher pressure and longer holdout between shifts).

4wd is often needed when launching and retrieving boats since the ramps are not always the cleanest. Algae and other vegation tends to coat the ramp and you slip, this is probably why you slid backwards when you tried in 4h, the tires just wanted to spin (open diffs suck when it comes to this).

I would defiently check the fuel lines and filters on the boat. I know that since ethanol was introduced into gas, it does eat a lot of older style rubber hoses and tends to attract more water then regular gas does. This all adds up to a horrible experience for boat owners. This is also why it is more expensive to get gas on the water, they usually have ethanol free and the convience also drives up the price.

 

[lapriester]

I live where I must go up the highway on a steep grade to get home from work every day. If I give it some heavy throttle going up that grade it will shift to third and no matter what I do it won't upshift again unless I continue to rev the engine or until I'm over the grade and ease off on the throttle. That kind of response, and yours, from a computer controlled transmission is very normal. The computer senses load, throttle position, speed and other factors to determine when the tranny should shift. It uses averages that are usually out of whack in abnormal or heavy towing conditions.

Fords do it, Chevys do it, Dodges do it, Nissans do it....they all do it to some degree or another. Usually the only way to get them to shift is to apply more throttle.

Larry