Step motor part number for valve body 31705-3TX0C

[Istillbeleive]

I have a 2013 Nissan Rogue SV I bought less than a year ago. 3 months ago with really no warning I'm driving down the highway and suddenly my rpms spiked and I lost power. I barely made it home. Put a scanner on it and only one code came up, P1778.

And I already know my chances of replacing the stepper motor fixing the issue is slim. But, I'm on a fixed income and it's either try this or scrap the car. That being said, I ordered the replacement and it doesn't fit. I have looked everywhere and haven't been able to find the specific part number for my vin. I did get my valve body number, 31705-3TX0C. However, I can't find anywhere that shows the stepper motor part number for that assembly.

If there's anyone that can give me the part number for the stepper motor I would appreciate it so much.

[VStar650CL]

Nissan USA doesn't sell the steppers as a discrete part. The only place you might obtain a Jatco part number for it is from a tran-ny shop in Australia or New Zealand, where they actually rework them. I doubt they'll be able to directly xref a USDM tran-ny, but they may be able to suggest a Jatco part number by year and series.

That said, P1778 in a CVT is like P101 in a Nissan engine, which is called a "MAF" code but rarely reflects a MAF problem. P1778 is a performance code just like P0101, and although it's called a "stepper" code, it almost always reflects bad fluid, a worn belt, or a blown front pump, not a bad stepper. Your highway experience was clearly a slipping belt, so if fresh fluid doesn't improve its attitude, there's about a 99.99% chance you're wasting your money and time on a stepper. Maybe a whole Valve Body, but even that's a crapshoot, it won't help a bad pump or belt. I'd inspect your belt first, then decide if it looks salvageable. This bulletin is for '10D tran-smissions and not 10A's, but the pics of how a trashed belt looks are completely applicable.
https://static.nhtsa.gov/odi/tsbs/2019/ ... 8-9999.pdf

[Istillbeleive]

Thanks for responding to my post. So, that was the only code I got but I can tell you when I drained the fluid, it was black like motor oil. I wonder if the original owner EVER had it changed. I've only had in for a few months. Until this happened I didn't even know it had a CVT transmission in it. I don't have access to any equipment to be able to inspect the belts and I don't know if what I did see is good or bad news but after I dropped the valve body I looked up in there to check it out. I did see the belts, I think, and everything seemed fine. Is there a way to test the original step motor. If I can get it to test good then obviously its something else right?

I really appreciate any help I can find. I've got the valve body out of the car and just waiting, hoping to find one. I can't really even afford a used valve body but I'm pretty sure I can find one when I get paid. Other than that the only thing left I can do will be to scrap the car. My daughter bought it for me less than a year ago and paid over 7k for it. It would be a shame

[VStar650CL]

First, use your smartphone to get a good closeup of the edge of the belt and compare it with the pics in the bulletin I linked. An endoscope is better, but zoom on a phone will suffice if you already have the VB down. Second, if you don't find belt damage, purging the fluid as much as possible may nurse it back to health. Do a second spill-and-fill after about 1K miles once it's reassembled. Transmission fluid is highly detergent and it will scrub out any crap left in the VB. Third, there's one tool you positively need to invest in, which is a VeePeak VP11 OBD dongle and a copy of the CVTz50 app. That will let you check the overheating record for the transmission, CVT-A and CVT-B, and also allow you to monitor the temperature and pressures. If the pump is shot, it will show up as low line pressure.

[Istillbeleive]

I took the photos but I can't really tell if I was able to capture what I need to see. I atached them here to see if anyone here can see anything. I did learn the step motor turned out to be the right one. Still, I don't want to move forward unless I can figure out if its even worth trying.

Again, any help is greatly appreciated

dana

[VStar650CL]

You really need a pic of it off the pulley (I know that's hard to get without a borescope). However, I don't see any sign of scuffing on the pulley, which is a good sign. Fluid that's so far gone that it blackens can cause a host of issues without any help from the metal parts, so you may have lucked out. If you didn't find any big pieces on the magnets in the pan (fine shavings are normal), I'd say try putting it back together with fresh fluid and see if it behaves itself. If so, give it another change in 1000 or so as I suggested and you should get some more miles out of it .

[Istillbeleive]

Well, there were no big pieces of metal in the pan at all. It did have shavings on the magnets and I thought I saw some shavings in my photos but nothing bigger. I ordered my filters and gasket that will arrive Friday. I'll post an update on my progress. Either way, I think it might be best to sell it. From what I've read, once these issues begin, its only a matter of time.

Thanks so much for you input. I appreciate it so much.

[VStar650CL]

From what I've read, once these issues begin, its only a matter of time.

Sadly, that's generally true, especially with a unit neglected enough to have black fluid. But it will be a lot easier to sell if it moves when you put it in gear. I'll cross my fingers for you.

[Istillbeleive]

Ok, so I just have one more question. I figured out what the problem is with my stepper motor, I think. Apparently, I was supposed to put the car in neutral before dropping the vb. I didn't do that, I left it in park. I'm not sure but I wonder if thats the reason my original stepper motor is extended while the replacement is not. If so, is it going to create a problem when I reinstall? I would have to put everything back together, put the car in neutral, and start again. Which I'll do if I have to. I want to make sure I cover any potential issues and now that I know I should have put it in neutral, I hope I didn't screw the whole process up

[VStar650CL]

The stepper is just a back-and-forth actuator, I don't think the TCM actually knows what position it's in. That's why P1778 is a performance judgement and not a hard code, because the TCM throws it when it runs the stepper through its full range and the output ratio still doesn't match. So as long as you have the arm "on the hook" I think you should be okay.