About 2 weeks ago my TCM failed and went into safety mode and locked the transmission in 4th gear. The issue was a broken contact inside the TCM for the front brake solenoid. I drove the rest of the way to work and back home in 4th gear. Most of my trip was on the freeway so I kept the speed about 75mph. Engine RPM’s about 3500rpm. A few miles were on the street but I took it real slow when accelerating from a complete stop. I didnt wanna burn up anything in the tranny. Then I drove the car to my dad’s house where I had the space and tools to fix it. So all in all, about 120 miles total driving in 4th gear. About 100 of those miles were on the freeway. Anyway, I dropped the valve body and opened the TCM and re-soldered the broken connection and closed it back up and installed everything back on the way it was.

Heres the issue. The transmission works now, but I have this faint whine only in 4th gear. Also, when I leave the car parked overnight and let it cool down, the next day when I start the car and drive off, it shifts fine thru 1st 2nd and 3rd gear. But once it hits 4th, I get a loud whine and it feels like my transmission slips and my RPM’s shoot up. This happens maybe once or twice, then it shifts fine thru all gears for the rest of the ride. Even if I turn the car off and on, it will not do it again. It only does it the first time I hit 4th gear after I have let the car sit and cool overnight. But the 4th gear whine is there at all times.

What does this 4th gear whine indicate? And what can cause my transmission to slip only in 4th gear after letting it sit overnight?

 

Are you 100% sure it has the correct amount of fluid?

 

I poured back in whatever I had drained. But I probably lost about a quart of fluid just from spilling here n there. I tried checkin the fluid level afterwards, but its difficult to tell lookin at the dipstick.

 

I've had good luck cleaning off the dipstick with brakleen when checking the level.

 

Ok so I added a quart of transmission fluid and took the car for a drive. Same slipping issue is still there along with the 4th gear whine. My transmission might just be toast! I can buy a solenoid kit and replace all the solenoids on the valve body just as a last attempt to see if it fixes it. Any other ideas?

 

Well now it started slipping in 1st and 2nd gear as well. Its very random. It only does it sometimes though. Whenever its normal, I can get on the gas pretty hard and it wont slip. It just slips whenever it wants 🤔

 

Do you have any new TCM/CEL codes coming up with the slipping???
I would replace the entire valve body vs. replacing the solenoids alone. There are a lot of small orifices and channels within the valve body that can wear, so I'm afraid replacing solenoids may or may not fix your problem.

 

No new codes. Over the past few days, the slipping got worse. It started doing it in lower gears too. It was enough to make the car almost undriveable at times. I dropped it off at a transmission shop today morning for them to check it out and possibly rebuild it if they end up having to. Lets see what happens.

 

If you're slipping multiple gears but have the correct amount of fluid then it's probably just smoked. You really need to be checking the fluid level with a dipstick though, if yours only has the little shorty one that isn't actually a dipstick then you can get a dipstick from an early 350Z which is an ACTUAL DIPSTICK.

 

I do have the full length dipstick. Oil level did look good but I added an extra quart just to test it out. Still didnt help though. Anyway, its gettin fixed at the shop now.

 

Picked the car up from the transmission shop yesterday. Dude said a one-way bearing was busted along with some other śhit. He rebuilt the transmission and I’ve been driving it for 2 days now with no issues.

 

Glad to hear you're back on the road
I think these transmissions have a low-coast/one way clutch, allowing the car to basically free wheel when coasting.
If you don't mind me asking, how much was the rebuild ?

 

How much does something like that cost? I can imagine rebuilding a transmission taking hours and hours and you might as well replace a bunch of old parts with new parts while you're in there and all of a sudden the rebuild costs more than a new transmission. These days anything that requires hours of human labor is just outrageous.

 

I took it to a few different places to get quotes. I got quoted $2000, 2500, $3800, $4500, and finally the last guy said $1500....and thats a pretty good price in my opinion. So he got my business. Also gave me a 1 year/12,000 mile warranty.

 

and now the MM works properly?