Help with Automatic Transmission issue
 

I'm kinda desperately looking for help with my 13' Z AT. I started to notice some issues about 1k km ago since I had Whiteline diff bushings installed. The problem is like this.

1. When on Drive(automatic) and coming to a stop it sometimes jerks slightly when AT is downshifting from 2nd to 1st. It's just noticeable, like pressing very slightly brake pedal. It does it about once per five downshifts and is rather irregular and only when car is warmed up. Only once it was very noticeable like a poorly executed MT downshift. I almost never downshift manually to 1st gear, and only in 10kmh range or so.

2. This worries me the most. When shifting from Drive to Park it can shift violently. Sometimes noticably, sometimes it's very audible and jerks the car with a thump. Only once there was a very loud thump and once there was a thump when I was already on Reverse and reversed about one meter. The latter happened on cold, former on hot. It's more irregular than issue #1 and there is no rhyme no reason. Going from Park to Drive never produces any issue. It's smooth and inaudible.

3. Very rarely manual downshift from 4th to 3rd is slightly delayed

4. Going from 2nd to 1st (auto mode) produces a click sound. It's also audible when going from Drive to Park

5. Right away after installing Whiteline's diff bushings I noticed shifting being slightly harsher but I address it to harsher diff engagement due to harder bushings.

Otherwhise, my AT shifts fine and smoothly from 3rd to 4th and up. I don't experience any slippage and car accelerates as it should. Right away after installing Whiteline's diff bushings I noticed shifting being slightly harsher but I address it to harsher diff engagement due to harder bushings. I've changed AT oil about 200km ago and it didn't really help. The only mod that is worth mentioning in this situation, beside bushings, are more aggressive JUN exhaust camshafts. Could electronic AT valves be the culprit?
I'm sorry for creating another topic but I've searched through and through and couldn't spot identical issue. Thanks in advance.

I have a 13 with AT and z1 bushings and I’ve felt the 2 to 1 shift and also a 1 to 2 shift can be harsh at times (even triggers the ecutek knock indicator). It did these even before the bushing swap though and really the thing that helps the most is changing the fluid then it smooths out for a while. I’m not too sure there is any issue with yours and may just be normal as I’ve had others say the 1-2 shift can be a bit harsh.

Are you talking about AT mount bushings or diff bushings? Did you experience the thump as I'm sometimes experiencing?

I’m not sure if I’d call it a thump but it’s an obvious harsh shift sometimes. Yes it’s the diff bushing but like I said it did it before so that’s not the issue.

Thanks for your reply. I'm mostly worried about reverse. Anyone experienced something similiar?

Regarding your transmission this is normal operating. Leave your transmission in auto mode don’t manual shift your transmission. Let your transmission do it’s job in auto mode. First step would be to have your transmission fluid changed at a Nissan dealership service department you trust or transmission/driveline shop you trust if you are not able to change your transmission fluid yourself. Also it is possible your transmission fluid level could be lower than it should be. Give your transmission time to shift as well from park to drive etc. After your transmission fluid is changed you should notice somewhat of a difference. Have your Z diagnosed if necessary. Once you install polyurethane or solid differential bushings they will never be as quiet as the Genuine Nissan OEM hardened rubber liquid filled differential bushings it’s the nature of beast.

Thanks for your reply. How could I forget to mention that I did change oil in a trusted shop (not a dealer). Didn't change much.

Regarding shifting from P to D. I'm always shifting from P to R, waiting about a second and shift to D. R to D was never a problem. It was P to R and D to R.

Also, why are suggesting to not use manual mode?

Wonder if that shop did the refill procedure properly and used the correct fluid! :confused: