Notchy shifting from 1st to 2nd on my 78 280Z 5 Speed

[fandsw]

Need some help with a diagnosing an issue I'm having with my Z. Background on the car: 78 280Z 5 speed, 30K miles, new clutch, pressure plate, tranny fluid and clutch master cylinder about 800 miles ago.

Shifting from 1st to 2nd the shift is notchy and grinds a little, especially when the car is cold. Shifts into all other gears fine. The 1st to 2nd shift improves once the cars warms up, but it's still not 100% smooth. No throwout bearing noises or anything else abnormal.

My next steps are getting the clutch adjusted, as the pedal is about an inch closer to the floor than it should be per the FSM. Tried getting to the adjustments myself, just can't quite get to them as I'm not a small guy. I've also picked up some Royal Purple tranny fluid as it's supposed to improve shifting and I do not know what fluid was put in by the previous owner when he did the mechanical restoration.

Am I on the right track or missing something?

[Zed Head]

Those all sound like the right things to do. I used Redline MT-90 myself to solve a grinding issue at high RPM from 2nd to 3rd. It also helped the cold notchiness. I don't know much about Royal Purple in Z transmissions. I've read a few good accounts about the Redline MT-90 though, and it definitely helped my transmission, a 1978 5 speed that I transplanted in to my 76 car.

[Z train]

How does it shift without using the clutch?

[Z Greek]

I go with Zed head, Redline Oil is the BEST, I have used it for years. Adjusting your slave cyl. rod to give you full throw on your pedal should help also.

[fandsw]

Thanks for the answers guys, glad to see I'm on the right track. Did some more checking, looks like Redline MT-90 does have more positive reviews, although the reviews on Royal Purple aren't bad either. Already have purchased the Royal Purple, but don't mind spending another $30 getting some Redline if it is better.

I'll let y'all know how it turns out.....

[olzed]

Can you engage gears easily from stationary?

Does the car creep with your foot on the clutch?

[coop]

I used to have a 510 that did exactly what yours is doing. I put Redline MTL in and it was like installing a new transmission. I highly recommend it. Totally cured the cold weather related grinding.

[jmortensen]

I'll disagree on the Redline, particularly the MT-90, don't know about MTL. SWEPCO 201 works better, and I think synchromesh does as well. Related thread:

http://forums.hybridz.org/index.php/topic/103084-1-2-2-3-bad-synchros-1980-fs5w71b-5-speed-buying-time-swepcoatf-or-mt-90/page__p__964470__hl__%2Bredline+%2Bswepco__fromsearch__1#entry964470

[Zed Head]

This is a little awkward. That's me over on Hybridz. I never planned to post on these forums so I have multiple identities.

To clear up my situation - with my well-used 1978 5 speed, I had gear-grinding from 2nd to 3rd at high RPM using Valvoline 75-90W gear lube. I went to Redline MT-90 and the problem disappeared, and the low temperature notchiness also. It was like magic.

Subsequently, I installed a well-used 1980 5 speed from the local wrecking yard and with MT-90 I had gear-grinding from 1st to 2nd and from 2md to 3rd. I never tried the Valvoline 75-90W in this transmission because the MT-90 had worked so well in the 1978 transmission. That's when I started the thread on Hybridz and, at Jon's suggestion, tried the Swepco 201, Swepco 201 50/50 with ATF, and finally Swepco 201 at 75/25 with ATF. That blend is working very well at this time.

I should have added some detail, but based on your description of slight grinding when cold, the Royal Purple or Redline, along with the clutch adjustment seemed like the right path. But, in retrospect, since you don't know what's in there now, maybe going directly to a Swepco blend would be the way to go. I didn't want to complicate what seemed simple, but may have over-simplified. I tried to summarize at the end of the Hybtidz thread but it seems like the solution probably depends on what problem you're trying to fix.

fandsw, in summary, it's difficult to tell what is causing your problem, but the fluid used can definitely have an impact. You can see in the post #11 in that Hybridz thread that I'm currently using 75% Swepco 20, 25% Dex-Merc ATF blend. It works very well, for the bad synchros but is still a little bit notchy when cold. It's only like that for a few shifts though.

To add to my own perplexation, I just took a junked ZX tranmsssion apart (it sounded like a blender on a motor I have set up to run in my garage, due to someone breaking two shift forks and destroying the main countershaft bearing) and found that the brass synchros looked fine but the dog teeth on 2nd gear were wasted. I had thought that the brass was supposed to go before the steel. It's possible though that someone "rebuilt" the trans with new synchros but left the bad gears in.

Anyway, good look and sorry for any confusion. By the way, you might be able to tell something about the fluid that's in there by the smell. The synthetics like Redline have kind of a sweet smell, while the old-style fractionated fluids smell like the dead prehistoric lifeforms they're derived from.

[jmortensen]

You said on hybrid z that choosing oil is like voodoo. Really it's not. If it works to make old busted up transmissions shift better, then it will also make pristine new transmissions shift better for longer as well. Swepco and synchromesh work better in every case, not just when trying to prolong a rebuild.

[Zed Head]

I wrote a whole dissertation in reply, but realized that it all comes down to the fact that nobody has really shown that to be the case. No offense. I do appreciate your sharing your experience.

I've done more straight comparisons between lubricants than any thing I've seen on the forums so far. I ended up at 75% Swepco/25% ATF. Is it better than 50/50? For my one situation and what I wanted, it was. Jon Coffy seems to know quite a bit, and he reported that the Swepco blend destroyed the synchros in his worn transmission. Who to believe? It's a problem.

Plus it seems to me that a worn transmission is not the same as a new transmission. New transmissions have more texture on the baulk ring, sharper baulk ring and dog teeth, sharper splines and tighter clearances. It seems to me that these factors would be affected differently by the lubricant used. If new and old were the same, why doesn't plain old 75-90W keep working as the transmission ages?

There are tons of opinions out there but little reason shown for the results. Most accounts are "I tried X and it worked - I'm happy and done". We haven't even mentioned Synchromesh yet. Without a good study on the subject, I can't say that one is better than another, for solving any distinct problem. The studies that can be found are all suspect in that they're done by companies selling a product.

That's the essence of what I meant by voodoo. Who knows, the OP might have 85-140 wt in his transmission and sawdust to stop a leak? Anything might be better.

Crap, I wrote another dissertation. Oh well.

[jmortensen]

I worked for a Porsche shop that used SWEPCO in everything from fresh rebuilds to brand new cars to cars with 200K on them. My boss had used it since it became popular with Porsche-files probably 20+ years before the time I got there. In fact, my boss was such a believer that if you were a new customer he would replace whatever you had in there with SWEPCO whether you asked for it or not. Had several pissed off customers in the office who had just put in Redline, but he would tell them to take it for a drive and if they wanted it switched back he'd do it at no charge, nobody ever took him up on that offer while I worked there.

I think John is still operating under the assumption that GL-5 oils are not safe for brass synchros if the temp gets over 250 degrees. However, this is not correct if the oil is also MT-1 rated, which just about every GL-5 oil, including SWEPCO, is. If they are MT-1 rated, they're safe for brass at any temp. You can go further down the internet he-said she-said rabbit hole if you like, but I'm 100% confident that SWEPCO won't hurt your synchros. This comes from my own years of experience, but more importantly, my ex-boss's decades of experience with customer cars.

http://www.swepcousa.com/lubesite/products/h201.htm