Trouble Downshifting to First Gear?

[Pilgrim]

Never seen that chart before! "Or type Dexron" is an interesting addition. My tyranny has lasted 130k miles with the original and later synthetic gear oil, so I'm not motivated to change.

[Zed Head]

It does say "or", for sure.  The history of Dexron doesn't offer any clarity either.

https://en.wikipedia.org/wiki/DEXRON

I will probably just use Synchromesh synthetic fluid in any manual transmission I have in the future.  Seems like some genius fluids engineer created the ultimate fluid and it works for everything.

[siteunseen]

21 minutes ago, Pilgrim said:

Never seen that chart before! "Or type Dexron" is an interesting addition. My tyranny has lasted 130k miles with the original and later synthetic gear oil, so I'm not motivated to change.

Do you use Red Line? That's what I like. Nobody stocks it here so I get it from amazon.com about $15 a quart? 

Wait one second! My transmission is mt-90 red line.

 

 

[dutchzcarguy]

I once experimented with a 5 speed gearbox that would'nt go from 4 to 2th gear without a lot of noise..  i put in SLICK50  does someone here know that stuff?  The gearbox is now after ~30000km again a problem shifting from 4 to 2th or even to 3th.. 

I ask myself, how can i get the oil AND!  the SLICK50! out of there to test an other oil. (before taking it apart and get new sinchro's in?  It's a FS5C71B so a very rare gearbox with rare sinchromeshes..)

[Patcon]

Paint thinner? That's what motorman7 uses to degrease old parts

[dutchzcarguy]

Yeah.. paint thinner i could try.. maybe fill the gearbox with diesel might work to..?

I wanted to ad.. if i go from 4 to 2th realy slowly it works without the horrible noise..  i can feel and hear the turning of the gears and hear them stop..(i push the lever against 2th gear but don't go into 2th) then i can shift into 2th without noise.

But i think a new set of sinchromeshes would be the best solution.. but where do i find those for a FS5C71B?  (euro 5 speed 240z box)

[Pilgrim]

Are you double - clutching your downshifts? I sure would be. It greatly reduces the work of the sync rings. I do it now by reflex on my ZX.

[Zed Head]

On 10/10/2020 at 3:42 AM, dutchzcarguy said:

i put in SLICK50  does someone here know that stuff? 

I remember Slick50.  Based on how synchro gears work, that seems like a not-good choice for transmission fluid (no offense).  It has PTFE particles in it to minimize friction.  Synchros need a balance between friction and viscosity to allow the speed matching to occur.

If you want to take a chance with $50 I'd try the AC Delco Friction-modified Synchromesh before tearing the transmission down.  I'd just let the other stuff drain out and refill with Synchromesh.

Otherwise, there's a post on Hybridz about modifying Porsche synchros to work in the steel synchro 5 speeds.  I think that FS5C has steel instead of "brass" (yellow).

https://slick50.info/manual-gearbox-treatment/

http://skepdic.com/slick50.html

https://www.ftc.gov/news-events/press-releases/1996/07/quaker-state-ads-slick-50-are-false-and-misleading-ftc-charges

https://forums.hybridz.org/topic/92246-to-people-with-experience-with-the-datsun-comp-5-speed-need-parts-for-one/

Edited October 11, 2020 by Zed Head

[EuroDat]

I tried to buy the AC delco/GM Friction-modified oil here locally (Europe), but couldn't find it anywhere. There was a company in Italy, but he didn't stock it anymore.

I ended up ordering it from the states, but they cancelled and refunded the money because it was considered dangerous goods being flamable. Thats is going back 5 years ago, but I doubt much has changed.

Edited October 11, 2020 by EuroDat

[Patcon]

2 hours ago, EuroDat said:

I tried to buy the AC delco/GM Friction-modified oil here locally (Europe), but couldn't find it anywhere. There was a company in Italy, but he didn't stock it anymore.

I ended up ordering it from the states, but they cancelled and refunded the money because it was considered dangerous goods being flamable. Thats is going back 5 years ago, but I doubt much has changed.

Is it possible to get a state side member to ship it to you?

[Zed Head]

Pennzoil's brand seems to work just as well.  Internet has it that Pennzoil developed the formula for GM (AC Delco).

I wonder how Dutchzcar managed to find Slick50 in The Netherlands.

Just remembered though that the other magic fluid for Porsche synchros is Swepco 201.  Diluted with ATF for the Nissan units.  But it came from Porsche world, a guy who owned a Porsche shop.  JMortensen has posted about it.  Maybe Swepco 201 can be found, it's more of an industrial fluid.

https://www.swepcolube.com/products/swepco-201-multi-purpose-gear-lube

 

[red67]

Back to my leaky speedo, can I change the seals under the car, or does the cable have to come out?  Thank you!