Hey guys, I'm kinda at a loss.

I recently took my manual transmission (Touring) 350z to the shop to fix the clutch slipping. They replaced:

• Transmission (Z1 Motorsports CD009)
• Clutch (OEM)
• Flywheel (Z1)(The shop installed my z1 flywheel in the relief hole last time, which caused some issues when I got it back initially with the new parts but it ran well after they fixed it)
• Master & Slave Cylinder (OEM),
• Crankshaft position sensor (I put that in, OEM)
• Timing Chain, & Camshaft Position Sensors (The last two were free because of the improper flywheel install because they thought that was causing issues)

I have had it less than a month and have driven it daily. I don't drift it, burnouts, or clutch dumps. (It's too expensive since I don't have my own place or time to work on my car that much.) I will accelerate quickly, but I try to shift smoothly between gears even with quick acceleration. I also downshift if I need speed and revmatch, but I don't try to push it to its max speed or full pedal when accelerating. I'm confused about why the gear seems to be slipping. I can feel it slip, and I'm really at a loss. Is there anything I can check or tighten with my clutch? I have tried to look up stuff online but I keep turning up with not helpful answers or recommendations to replace the parts I already have.

I don't have any oil or fluid leaks from the engine or any parts. The only thought I've had is that maybe somehow oil got in the bell housing, but I don't know enough to know how to check.
I notice the slipping the most between 1-3 gear, Ive looked at gear rpm ratio charts and mine seems close but slightly off (more off when accerating). When I start pressing on the pedal to accelerate in second gear is when I notice it the most. On hills, if I hold the pedal steady, the mph still drops slowly despite not releasing the pedal. Im pretty sure I can also hear it slipping when I accelerate (yeehaw)

 

so your clutch is slipping, but the shop replaced almost everything except the clutch? why would you replace the whole transmission and everything around it because the clutch is slipping? or did you mean to say that one of the gears was slipping?

 

This is going to sound obvious but.... just take it back to the shop who did the work. They got thousands out of you. Have them actually fix the original problem.

 

I did say that they replaced my clutch but with an OEM one I'm pretty sure (maybe an exedy idr)

 

Yeahhh that's what I planned since all the parts should be under warranty, but I wanted to see if anyone has any ideas before I do.

 

You did not really explain what happens when clutch slips. The RPM's will shoot up in gear and you are not actually going as fast as the RPM's indicate.

 

Sorry I should’ve explained it better. The rpm will shoot up faster than the car accelerate. So in second gear it will get up to 3,000rpm at like 21-23 mph then catch up to about 28-29mph after a few seconds

 

did you do a proper break in

 

I don't see how your symptoms have anything to do with the transmission if it's a manual. The RPM is irrelevant with a manual. If you had an automatic, then yeah, that would be a symptom. You did not need a new transmission in that car.

 

The last one broke the clutch fork and damaged a bunch of parts. The transmission fluid was meta soup just about. Also rpm is relevant because in manual you are shifting the gears and if your rpm doesnt match you will damage something. If the rpm is not matching the correct mph for that rpm, then something is slipping. Maybe I'm missing what you're saying.

 

Yes i only started having issues after putting I think 2000+ miles or whatever it currently is at

 

My money is on oil/grease contamination or glazing issues on the flywheel/pressure plate surfaces. I had similar issues with the old clutch/flywheel in my Z when I 1st purchased. When I took it apart to fix the problem, there was still plenty of meat on the clutch disc, but the friction surfaces of the flywheel and pressure plate were a mess. Maintenance records from previous owner indicated a Dealership had replaced the transmission, so I suspect a tech at the dealer caused the problem or the previous owner didn't know how to drive a manual.

The OEM clutch disc isn't bad, but the OEM flywheel becomes a problem as they age. Exedy makes good clutches, but if you get grease on it, it's pretty much game over. The grease will soak into the friction material and ruin the clutch disc, same for brake pads. The flywheel and pressure plate can be cleaned up.

If the shop warranty's the work, I would be curious to see pictures if you can get some.
Cheers!
-Icer

 

Just curious- what was the final cost of the work?
I went away to a member/guest golf tournament out of town for a week a few months ago & my wife drove the z & when I returned the clutch was on its last breath. No finger pointing.
My repair cost $2,700.
Still enjoy the damned car.

 

Im not really sure, the parts cost more than the work. I made sure to buy the parts myself if I could because they were getting or wanting to ship parts with like next day shipping and the cost for the parts would've been exorbitant. Thankfully Z1 motorsports had all the parts I need, and I was able to directly ship the transmission and other parts to them. The Parts cost like 3000-4000 (transmission wasn't cheap) and the labor cost I think about 2000ish?

 

Thanks Icer, I appreciate the advice! It doesn't seem to be slipping now, so I'm hoping I just was overthinking it, but it's weird because I was so sure, and now I'm not. It also might be that I had to change out my front wheels for the OEM because one got bent from a tire pop, and the OEMs just might feel different (they also weigh more so maybe that as well Im not sure)