CVT immediately stalls engine when in Drive or Reverse gears

[tedsar]

Car just rolled to 150k yesterday and today on my way home to enjoy the weekend, it stalls at a red light. Felt like it stayed locked in gear, or like a torque converter was locked up (does this even have a TC?). I haven't had a chance to check the obvious things like fluid leaks/level, but I did hook up the CVT OBD monitor and it seems to be reading normal in park and neutral. When I give it gas the primary and secondary pressures go up slightly. I even switch it into R or D for a split second and see the pressures jump significantly. No CVT or engine codes (of course). Anything else I can check? Maybe exterior trans wiring? Thanks in advance!

[tedsar]

Also wanted to add that the CVT was exhibiting issues about a month or so prior when stopping abruptly. It would act like it wanted to stall, almost as if the TC lockup couldn't disengage fast enough. It didn't have issues on normal stops.

Dealership recommended a CVT replacement back in 2020, so I got another 3 years out of it. Do I cut and run or try a valve body replacement on my own for a few hundred and see where that gets me? I'm assuming these engines will run forever.

[VStar650CL]

The CVT's do have a lockup clutch in the TC. They don't fail often, the problem is more likely in the Valve Body than the TC.

[tedsar]

Yeah it was the valve body. I swapped in a remanned and it worked ok, except it wouldn't shift into drive, only drove in low and reverse gears. I was just trying to get it driveable so I could get more for it in trade. Instead I'll be scrapping it for $675. When I dropped the trans pan there was a bearing carcass (like attached pic) stuck to the magnets. So at some point a whole bearing detached from the guts of the cvt and made its way past everything and into the pan. I opened up the original valve body after testing all of the solenoids for functionality <- they all worked the same as the new valve body, and I found metal shavings blocking a few holes in the valve body. Not being in the mood to drop the pan a 3rd time, I admitted defeat and will be leaving the nissan community. It was fun while it lasted! Thanks for everyone's help over the years with this dumb CVT.

[VStar650CL]

When you dropped in the new VB, did you program the TCM with the new IP settings? If not, the no-shift was probably from the TCM using the old IP values. Sometimes they run with old IP's, but they're never well-behaved and often won't move at all.

[tedsar]

I swapped the rom chip with my stock chip but I did not reprogram anything.

[VStar650CL]

The TCM only reads the ROM when you perform the erase-and-read procedure. So you were basically running the new VB with IP data from the old one. If you still have the car and you have a copy of CVTz50, I'd try doing an erase-and-read and see if it becomes drivable enough to sell.

[tedsar]

Looks like the app will only erase and read from a cvt8. Mine is a cvt7.

[VStar650CL]

I haven't tried it, but as far as I know the algorithm is the same for all the trannies using a ROM in the VB. You could try it, or I'm sure the CVTz50 support people can tell you for sure. They're good about responding to email.