Automatically downshifting D to 3rd

[WA_Snoq]

I've got a 2008 Titan 4x4 with close to 60k miles on it. About 8k miles ago I started to notice my Titan automatically shifting from D to 3rd gear going downhill around 45mph. This was odd since I put all the miles on this truck and it never did this before.

I took it to the dealership where they ended up replacing the rear differantial, transfer case and left front hub. This didn't help the problem and about 1,500 miles ago they put in a whole new transmission.

Unfortunately, still today my truck continues to downshift more frequently going down hills. It skips right past 4th gear into 3rd. If I quickly hit the gas it will go back into D.

The dealership doesn't seem to know what's going on. I've looked on forums on the Titan and have seen things that the trucks are programed to do so. However, I find it odd this started after 50k miles and not sooner.

If anyone else out there as any experience with this it would be greatly appreciated to hear feedback.

[desertruner09]

Are you tapping the brakes while going downhill? If you are, then this is a feature of the truck. When you tap the brakes while going downhill, the truck will downshift into 3rd for engine braking. However, in my 06 at least, it seems to be somewhat picky. Sometimes it works for me, sometimes it doesn't. If you shift into 4th, this feature is disabled if I remember right.

Now if you aren't tapping the brakes and it just shifts into 3rd, then that isn't suppose to happen.

[WA_Snoq]

Yes the brakes are being tapped when this occurs. However, I find it extremely odd that for the first 50k miles of my trucks life this never occurred once. Then one day it started doing it and it continues to do it more and more. Also, it's interesting that in all the times I’ve had my rig at the dealership regarding this they never once mentioned this feature. Seems like a feature that Nissan should allow you to enable/disable at your leisure versus it’s continued annoyance.

[desertruner09]

Originally Posted by WA_Snoq

Yes the brakes are being tapped when this occurs. However, I find it extremely odd that for the first 50k miles of my trucks life this never occurred once. Then one day it started doing it and it continues to do it more and more. Also, it's interesting that in all the times I’ve had my rig at the dealership regarding this they never once mentioned this feature. Seems like a feature that Nissan should allow you to enable/disable at your leisure versus it’s continued annoyance.

Yeah, that is odd. However, like I said, my 06 is very picky about when this feature works and when it doesn't so maybe your 08 is (or was) too. Also, maybe the dealership updated your ECU/TCM so that this feature is more "aggressive".

From what I have learned (and what others have experienced), dealerships aren't always the best place to get information on your truck sadly. Most of them have no idea what they are talking about.

I agree on having a disable button or something, since if I want engine braking I'll just shift to 3rd on my own. But now days, it seems like all car manufactures want is more "features" than the other with no way to disable them. Try manually shifting into 4th on a hill to disable it.

[WA_Snoq]

Yeah, I’m going to check with an transmission shop to see if they might be able to do a better diagnoses. This is my second Titan but it’s with 100% certainty it will be the last Nissan I ever own. Better my transmission issues, tail pipe rusting and falling off, sensor button not working and all the issues we’re experiencing with my wife’s 09 Murano we’re very dissatisfied with the brand.

Thanks again!

[.camou.flage.]

There's a thread on here about resetting the ECU and doing the throttle re-learning. Not sure if it would help or if you have already done it, but its free and looks like it only takes a couple minutes. Couldn't hurt