pbn85

iTrader: (2)

All-

My friend and I checked out a 2007 Z (for him). Car checked out to be really good and being sold by the original owner with 70k miles. It drives great also, no issues with the gearbox. The seller admitted, and I don't know why, that he very frequently would "get on it" on the highway when shifting 4th to 5th, usually around 5k RPM. Even though the car drove wonderfully when I test drove it (high rpm and downshifting), my buddy is worried about any excess wear this may have caused.

The seller did say that though he often did the 4-5 shift at high rpm, he never slammed gears, grinded gears or fast shifted it. For some reason I believe him. He seemed like he really knew what he was doing and the car is mechanically mint and well taken care of. Clutch is original and feels new and tons of maintenance records.

Any thoughts on if this may have accelerated synchro wear even when the high rpm shifts were done properly?

350zchad

iTrader: (1)

This car is meant to "get on it", no unnecessary wear

dkmura

iTrader: (64)

A transmission guru I'm not- just a Z racer who knows a bit about trannys. Shifting this six-speed box at 5K is not particularly hard on syncros, unless the driver is ham handed or clumsy in making the 4-5 shift. If your buddy is worried about wear, he should have a UOA done on a sample of the gearbox lube. The analysis will tell you more about the condition of the tranny than anything else.

Your buddy has more to worry about a faulty CSC than the tranny IMHO. Tell him to refill the tranny with Redline MT85 when he refills it for maximum protection and performance from his tranny.

pbn85

iTrader: (2)

Appreciate the feedbacj....I'll send this link go my buddy.

But what point is getting the car and doing a oil analysis only to find out that the synchros are wearing? The idea would be to avoid getting the car in the first place if that's the case. I guess what I'm trying to say is that when I test drove it I tested that gear in high rpm and it was smooth, no issues at all, just the normal Z notchiness. Does that mean for the most part those synchros are fine?

For my own knowledge, I guess repeated high rpm shifting is fine so long as executed properly?

CT07Z

I'm not a transmission guru either but I would think that if you tested it out thoroughly and shifted into 5th at high rpm and it was smooth, then it doesn't have synchro problems. I could be wrong in saying this but RPM is irrelevant when it comes to wearing your synchros. Damage is really only done when you shift really fast, slam the gear when shifting and skipping gears. Anyone agree?

Buy that car if your friend is getting a good price for it.

dkmura

iTrader: (64)

Get a UOA BEFORE buying the car if you want to be thorough. The analysis will show whether a high percentage of soft metals that syncros and gears are made of are present in the sample. Or you could just go off your "seat of the pants" impressions of the tranny. But syncro damage is more likely when downshifts are forced/clumsy and gears are missed. I'd also check any maintenance records to see if the tranny fluid has been changed recently and with the correct (type and viscocity) lubricant.

pbn85

iTrader: (2)

So he bought the car and requested the blackstone oil kit today for the gear oil he wants an analysis done on. The previous owner had gear oil changed every 20k with receipts. If the analysis comes out to be normal, does that mean synchros are good to go?


I don't anticipate any issues with this car but going to what CT07z said, is it true that high rpm shifting if done smoothly will not cause any synchro issues and that it's really when you slam gears and shift super fast that'll cause accelerated wear? Now I'm just asking for my own curiosity

dkmura

iTrader: (64)

A UOA is the best indicator we have short of pulling the tranny out and tearing it down. If it comes back as being normal, it's also valuable as a baseline test for futire UOAs.

As for your second question, actually racing the same Z tranny for going on seven years sees it getting severe service indeed. Multiple upshifts near redline for lap-after-lap on road courses from one end of the country to the other. I find being relaxed, but precise, while making shifts keeps them clean. Believe me, there are bigger things (brake and tire wear, etc,) to worry about in racing!

pbn85

iTrader: (2)

Appreciate your feedback DK.

I drove the car a lot yesterday with my buddy (made a lot of trips to get car stuff) and I really got on it upshifting into 5th so high as 6k a few times and it was smooth as can be. If there was a synchro it surely would have grinded with that high rpm I assume. i expect the UOA to come back normal.

CT07Z

I bet the car is fine - if there was a synchro issue I would think it would have manifested during your high rpm shifting. Good call on the UOA though... report back when your buddy gets the results. I'd also love to know what effect high RPM shifting has on the transmission internals

travlee

iTrader: (8)

trans in the hr's dont have the problems the olders ones did.... BUT they have a crappy internal slave that is known for going on