doctorzaius

My FD shifts like a dump truck. Compared to other cars, it takes way more effort shifting 1-2-3 and 3-2-1. It improves when hot, but it’s never great. I’ve tried different oils (NEO currently) and I’ve rebuilt the shifter. No or little crunching, just feels like shitty syncros. This is a relatively low mileage car (~40k miles).

Does this sound normal? My other FD was fairly high effort at this mileage and I’m wondering if it’s really worth trying to solve (instead of figuring out some alternative). Are Mazda transmissions just like this?

scotty305

iTrader: (2)

I would try to get seat time in another FD to see if it feels similar to yours.

I think shifter feel is relative, depending what other cars you usually drive. I think the OEM shifter in my RX7 is significantly more effort than a late-90's Honda or a late-90's Supra, but only slightly more than an S2000, or a 2004 Subaru WRX STI, or an E46 BMW, or an RX8. I don't remember driving any manual-transmission trucks to compare against. My car was 10 years old with 45k miles when I got it, and I've never had the transmission open so I'm not sure what a new RX7 transmission feels like.

doctorzaius

I have another FD which I bought new, but its not really driveable at this point. From memory, shifting effort also increased in that one around 40k miles. So I feel like this is normal but kind of shitty.

BLUE TII

iTrader: (9)

I have driven/raced on two turbo FC transmissions and two FD transmissions (variants of each other) about 80,000 miles over the last 20 years.

They have never ever been hard to shift even with short shifter kits installed.
Just SLOW to shift with some being much slower than others.

I think you are trying to force it into gear before the synchros have matched rpms.
Incorrectly shifting like this makes the effort high and wears synchros so the transmission will become even slower shifting.

The FD has no transmission mount as it uses the Power Plant Frame tying the transmission to the differential instead.
This means the transmission moves Right to Left as you load and unload the drivetrain which makes it easy to miss 3rd and send it into 5th. This qyickly wears or brakes the 5th gear synchro since the synchro rpm difference is so much greater.

Banzai transmissiin brace is a very good preventative measure.

You should learn (on another manual car) how to drive without using the clutch and apply the mechanical sympathy you learn to diving when using the clutch.

Learning this mechanical sympathy will also greatly improve the speed of your shifts as your rev matching will effectively bypass the work of the synchros.

Removing/disabling the throttlebody dashpot and/or adding a lighter weight flywheel will greatly improve upshift speed.

Valkyrie

My car's shifter is relatively high effort, but it's a complete non-issue on the track.
It's probably the least pleasant shifting of any manual car I've ever driven, but my transmission is a high-mileage freebie from a friend...

boostin13b

Curious if the shifter reservoir being dry would cause something like this? I've never come across one that has dried out as they usually hold fluid well and don't leak everything out from there. You said you rebuilt the shifter, was the upper cup fluid checked or changed during this?

doctorzaius

I was able to remove about 80ml of oil from the tower. Less than I expected, but I figured maybe I didn't get all of it. Put 100ml back in.

Retserof

iTrader: (1)

Unfortunately, it does sound normal to me. I have 62K miles on my '94 and am the original owner, although the car had about 250 dealer miles when I bought it, so it had to endure some unskilled drivers. The 1-2 and 3-2 shifts can be a little crunchy if I am not careful and deliberate. I have also tried different lubes and like Amsoil MTG better than Redline MT-90, although either one shifts easier than the factory lube.

c0rbin9

iTrader: (2)

EDIT: I read this thread a little more. If it's nearly impossible to shift gears and getting worse, you could have a problem with the shift fork/pressure plate. At least that was the case on my car, and it required replacement of the clutch to resolve. Or clutch master/slave cylinders.


That's the FD tranny for you. It's the weakest point of the car, IMO.

Good fluid will help a little (Ford/Motorcraft XT-M5-QS is better than anything else I have tried, Redline was worse), as will not using a short shifter, but it's never going to be buttery smooth. I installed a taller shift **** for more leverage which helps reduce the effort a bit.

RX-8 transmission feels similar.

gracer7-rx7

iTrader: (16)

I'm going to be up in SF in a couple weeks with my FD if you want to compare.

doctorzaius

How did you diagnose this?

doctorzaius

Thank you for the offer. I actually have another FD but its not really drivable at this point. But that shifter is definitely lighter when the car is parked and I'm just rowing through the gears.

doctorzaius

Slight update: I replaced the NEO with Motul Transoil Expert 10W-40. The Motul is intended for transmissions that have a wet clutch and I had some of it on-hand for karting. It's significantly better.

Sgtblue

iTrader: (16)

Grease on the shifter ball and lower shifter bushing along with your gear oil in the reservoir??
1-2 on mine has always been a little slow since near new, and regardless of gear oil changes. But it’s never been truck-like and improves noticeably with heat.

I always figured it was characteristic of the transmission and maybe even something intentional from Mazda. I also hesitate to compare it too much with present day manuals since the car was designed over 30 years ago and the basic transmission design is probably a lot older.

iceman4357

iTrader: (2)

Not to derail the thread, but it amazes me how different everyones experience with transmission oil is. I changed mine out for Red Line tranny and diff fluid and it helped. I did notice recently that the differential and tranny are getting louder the harder/longer I drive. Maybe I will try the NEO as I have heard really good things.

Valkyrie

10w40 is waaaaaaaay too light for transmissions..... keep us informed. hehe.

doctorzaius

I assumed I would see that response. I sort of disagree as transmission oils all seem to be moving in this direction, even when used on older cars. And if I'm wrong I'll replace it with a t56.

Sgtblue

iTrader: (16)

Yeah, do that.

doctorzaius

You mean about the t56? Is that a bad idea?

fendamonky

iTrader: (6)

Can you explain what you believe a wet clutch is? And how that's similar to an FD transmission?

doctorzaius

I didn't imply that they were similar. What I said is that I had this oil on hand. I'm trying it because "why not"? If it works great. If not, it's just parts.

TeamRX8

iTrader: (2)

actually it’s not. 10W30 Mobil1 synthetic was a go to for racing trans fluid way back in the day before Redline and various other companies came on the scene.

doctorzaius

My understanding is that SAE scale for gear and engine oil are not the same. So, the mobile 1 10W30 would be something like 75W-85 gear oil (in terms of viscosity). Motul says that the oil I used is suitable for applications where the manufacturer calls for SAE 90W gear oil.

Valkyrie

Mind blown… what is even the point of having a scale if it’s not tied to some absolute level of viscosity…

doctorzaius

It makes no sense. Graphic by Amsoil: