[HoobsMan]

Hoping to get some ideas of what may be wrong with my Titan. Yesterday I was heading out into the desert down a sandy stretch of road, pretty fast admittedly. Rallying the thing I braked hard for a turn and downshifted from 3rd to 2nd, shouldn't be a problem of course, until when i tried to accelerate out of the turn at around 20 MPH, I pushed the gas pedal and there was absolutely zero throttle response. I could floor it and there would be no movement in RPMs... It was almost as if the throttle cable disconnected somehow. I came to a stop, put it in park, back in gear, and it still wouldn't provide any throttle to the diesel. I repeated this, and the second time it got going again, but barely. Finally, I shut the truck off, waited a minute, turned it back on and it worked fine, but then the same thing happened again, in a similar situation with hard braking. I bailed on my excursion and drove the truck back home in 2WD and didn't have a single problem.

When I was putting the truck back in park (while in 4H) trying to fix the issue and get throttle response on the pedal, i noticed the transmission would rev up to about 1200 RPM as I shifted back into park. Almost as if the computer didn't get the truck out of 2nd gear until I put it in park. It was super strange.

For context, This truck had a transmission failure and this new transmission only has about 1500 miles on it. In my opinion, since the truck was perfectly fine half the time, and all the time in 2WD, I have a feeling it may be a computer issue with shifting. I'm not sure why it can't handle shifting in manual, but there's definitely a problem.

If anyone has any insight into what this may be I'd really appreciate it. Thank you.

 

[QuikCoastie17]

Why don’t you just let it shift for you? It’s not really designed like a DSG or Tiptronic transmission to bang up and down the gears ‘rallying’ off-road. It’s designed for gear-lockout and ‘overdrive’ type situations for towing.

With that said-are you sure it was in 4WD? Actually engaged?I only ask because I had one occasion with mine that it wouldn’t shift to 4WD, it was in 2WD with the 4X4 ‘flashing’ at me. While it was flashing, the truck was shifting very erratic and had some very strange throttle response. The throttle felt like an ON/OFF switch instead of a throttle.

Are you stock or tuned? Pedal Commander or similar?

 

[HoobsMan]

Why don’t you just let it shift for you? It’s not really designed like a DSG or Tiptronic transmission to bang up and down the gears ‘rallying’ off-road. It’s designed for gear-lockout and ‘overdrive’ type situations for towing.

With that said-are you sure it was in 4WD? Actually engaged?I only ask because I had one occasion with mine that it wouldn’t shift to 4WD, it was in 2WD with the 4X4 ‘flashing’ at me. While it was flashing, the truck was shifting very erratic and had some very strange throttle response. The throttle felt like an ON/OFF switch instead of a throttle.

Are you stock or tuned? Pedal Commander or similar?

You're definitely right, but overall I always shift it in manual in any adverse road condition to have more control off-road when 4H is needed, the automatic shift points are awful. I do always keep it in automatic when i 4L, with diff lock and without. It does fine then at slow speeds.

yessir I am 100% sure it was in 4H. Completely stock, no pedal commander or anything similar.

 

[QuikCoastie17]

You're definitely right, but overall I always shift it in manual in any adverse road condition to have more control off-road when 4H is needed, the automatic shift points are awful. I do always keep it in automatic when i 4L, with diff lock and without. It does fine then at slow speeds.

yessir I am 100% sure it was in 4H. Completely stock, no pedal commander or anything similar.

All good info- the only other thing I can think of is too high of trans temps. You should pick up a cheap Bluetooth OBD reader so you can see if that’s what it is.

My truck acted strange on the beach one time last summer while driving in deep sand in 4H. The truck was trying to stay in 2nd gear and it was sorta ‘lugging’ the engine and then the pedal went numb. Looked at my EZLynk and saw trans temps were 200* instead of the normal 140* I usually see. Once it cooled off, I used the manual mode to lock it in 1st gear and the temps dropped quickly.

 

[RoadLessTraveled]

With a new transmission and just 1500 miles it is likely still working through its learning process, so that may be at play here. If it is trying to figure out how to shift for you and you are doing all this radical stuff the processor is probably working overtime and the operational map imperfect at best.


Sent from my SM-N960U using Tapatalk

 

[RoadLessTraveled]

I suspect the root of your malfunctions is that you are using the vehicle in a manner contrary to its design. Even in Pro 4X outfitting it is a 7500 lb vehicle on a heavy duty chasis with a big slow-reving torque oriented diesel motor.

This truck IS NOT some off-road rally truck willing to have its transmission slammed quickly up and down the gears. The transmission WILL overheat if continually worked over-hard creeping along without much airflow. The transmission was not designed to be continually used as a manual shifter, it was intended to allow occasional management of gear selection to avoid excessive automatic shifting under heavy load.

And yes, Nissan designed in some excessively early safeguards which can be annoying but they were trying to keep people from breaking a newly designed truck. It will shut stuff down if it is too hot. If you come off of a significant throttle input, go to zero then try to pound down the throttle again it will not add throttle, likely to prevent serious back & forth torque slamming the drivetrain & snapping u-joints/gears/driveshafts/etc. It is universally agreed by owners that this intervention is to soon, to much, and too long but its there so...

These trucks aren't built with operating systems containing unlimited processing speed, power, memory or coding. It isn't surprising that the system might become overwhelmed & stop working when being asked to manage far more operations, inputs & outputs than normal. This idea is supported by the fact that shutting it down and turning everything off, then restarting the truck resulted in the system working again.



Sent from my SM-N960U using Tapatalk

 

[HoobsMan]

I suspect the root of your malfunctions is that you are using the vehicle in a manner contrary to its design. Even in Pro 4X outfitting it is a 7500 lb vehicle on a heavy duty chasis with a big slow-reving torque oriented diesel motor.

This truck IS NOT some off-road rally truck willing to have its transmission slammed quickly up and down the gears. The transmission WILL overheat if continually worked over-hard creeping along without much airflow. The transmission was not designed to be continually used as a manual shifter, it was intended to allow occasional management of gear selection to avoid excessive automatic shifting under heavy load.

And yes, Nissan designed in some excessively early safeguards which can be annoying but they were trying to keep people from breaking a newly designed truck. It will shut stuff down if it is too hot. If you come off of a significant throttle input, go to zero then try to pound down the throttle again it will not add throttle, likely to prevent serious back & forth torque slamming the drivetrain & snapping u-joints/gears/driveshafts/etc. It is universally agreed by owners that this intervention is to soon, to much, and too long but its there so...

These trucks aren't built with operating systems containing unlimited processing speed, power, memory or coding. It isn't surprising that the system might become overwhelmed & stop working when being asked to manage far more operations, inputs & outputs than normal. This idea is supported by the fact that shutting it down and turning everything off, then restarting the truck resulted in the system working again.



Sent from my SM-N960U using Tapatalk

Thank you for the information. Definitely supports my theory that it was built by design, the transmission wasn't hot, I monitored that on the dash and that wasn't an issue (assuming the dash gauges are accurate. But, if there's universal claim that these safeguards come on too early, so to speak, that would still explain it. Quite frankly, it doesn't make Nissan look good if they were afraid drivetrain parts were going to break that early. My buddy will rip his stock F-250 in the same way with zero issues, it's just unfortunate Nissan kinda dropped the ball on this truck. you should be able to accomplish quick on the fly shifts in any truck. But its an older trans design, i guess it is what it is. Definitely still going to take it to the dealer. I was shut down for over 15 minutes, took multiple motor restarts. That should never happen.

 

[HoobsMan]

All good info- the only other thing I can think of is too high of trans temps. You should pick up a cheap Bluetooth OBD reader so you can see if that’s what it is.

My truck acted strange on the beach one time last summer while driving in deep sand in 4H. The truck was trying to stay in 2nd gear and it was sorta ‘lugging’ the engine and then the pedal went numb. Looked at my EZLynk and saw trans temps were 200* instead of the normal 140* I usually see. Once it cooled off, I used the manual mode to lock it in 1st gear and the temps dropped quickly.

Interesting. Yeah, it's something to keep an eye on. While ambient temp isn't gonna effect it too much, it was about 5 degrees outside, and this happened within 10 minutes of running it. Personally, I feel like any heavy duty drivetrain should be able to take that strain. towing 10000lbs uphill might get the trans that hot...

 

[RoadLessTraveled]

Interesting. Yeah, it's something to keep an eye on. While ambient temp isn't gonna effect it too much, it was about 5 degrees outside, and this happened within 10 minutes of running it. Personally, I feel like any heavy duty drivetrain should be able to take that strain. towing 10000lbs uphill might get the trans that hot...

I'd be a little concerned about how quick you say it over heated. (On the other hand I don't have to spend a whole hour throwing 100lb bags of grain into the back of my truck to realize that wildly swinging them around is hurting my back )

I have pointed out in the past that I feel the expectation that everything we can get our hands on should do whatever we feel like & work fine just doesn't seem reasonable. Nissan didn't market this truck as a backwoods off-road rally truck you could continually manually shift gears in, they didn't build it to operate that way, & if you bought it expecting that you might have bought the wrong truck. What they built was a substantial heavy framed truck with all the towing gadgets built in & a drivetrain designed to handle heavy loads on roadways (some of which might have compromised traction due to weather, road material or road design).

Sent from my SM-N960U using Tapatalk

 

[SamS]

Diesel? Could be your turbo is going bad. That’s the exact behavior my 2017 had.

 

[ToddC]

Hoping to get some ideas of what may be wrong with my Titan. Yesterday I was heading out into the desert down a sandy stretch of road, pretty fast admittedly. Rallying the thing I braked hard for a turn and downshifted from 3rd to 2nd, shouldn't be a problem of course, until when i tried to accelerate out of the turn at around 20 MPH, I pushed the gas pedal and there was absolutely zero throttle response. I could floor it and there would be no movement in RPMs... It was almost as if the throttle cable disconnected somehow. I came to a stop, put it in park, back in gear, and it still wouldn't provide any throttle to the diesel. I repeated this, and the second time it got going again, but barely. Finally, I shut the truck off, waited a minute, turned it back on and it worked fine, but then the same thing happened again, in a similar situation with hard braking. I bailed on my excursion and drove the truck back home in 2WD and didn't have a single problem.

When I was putting the truck back in park (while in 4H) trying to fix the issue and get throttle response on the pedal, i noticed the transmission would rev up to about 1200 RPM as I shifted back into park. Almost as if the computer didn't get the truck out of 2nd gear until I put it in park. It was super strange.

For context, This truck had a transmission failure and this new transmission only has about 1500 miles on it. In my opinion, since the truck was perfectly fine half the time, and all the time in 2WD, I have a feeling it may be a computer issue with shifting. I'm not sure why it can't handle shifting in manual, but there's definitely a problem.

If anyone has any insight into what this may be I'd really appreciate it. Thank you.

The only time I have had issues like that is if I didn’t turn off the traction control. It’s like the trans would stop working and then after a while “ bing” it would shut it off for me. Ever since then I do it manually and never have that issue.