13 replies to this topic

[Johnny D]

Can someone enlighten me, is there a trick to shifting under high g-loads? I often have trouble upshifting from 2nd to 3rd coming out of turns like Infineon #7 or Laguna #2. I thought it was just my transmission wearing out.

Thanks, Ray

[Johnny D]

I thought once because I didn't use MTL, I had problem off the last turn at LS.
But mostly I thought I was at an angle under G's that I wasn't in the same position when I wasn't. The shift movement wasn't the same.

But yours is interesting, oil forces to the side walls starving the tranny to shift?
J~

[Johnny D]

Doubt it. Once the input shaft is spun up, oil is flailing around the inside of the trans like crazy.

[Johnny D]

I agree. So I have the tranny that came with my car, with as much as 130K.
Is it time to replace/rebuild?
I was thinking it was the nut behind the wheel.

I'm with Ray, can someone enlighten me?

[davew]

My opinion is 2 fold. The nut behind the wheel and the trans is worn out.

The easy part is to rebuild the trans. Miata transmissions show internal wear at about 40,000 miles. That 130,000 mile trans is probably no better than what you have in the car. Everyone is amazed how much nicer a fresh trans is compared to the worn out unit. Think of it as a pair of old worn out tennis shoes. The're comfortable and seem to be just fine. Untill you buy a new pair and realise just how bad the old ones are.

The hard part is to change the driver! Inside the shifter body there are 2 springs that center the shifter in the 3-4 gate. These springs are not very strong to begin with, and are worse with age. It takes very little side force to move the shifter into the 1-2 or 5-R gates. If you are holding the shifter with your fist, you are going to over power those 2 springs. You have complete control of the shifter, and YOU have to hit 3rd gear perfectly, or you will miss the shift.

Let go of the shifter!!!! You need to push it forward, out of second, into neutral. Delay a split second for the 2 springs to center the shifter, then simply push forward into 3rd gear. I like to palm the shifter, catching the top of the knob in the joint between my 1st and 2nd fingers. This gives me a good feel for what the shifter is doing, but does not overpower the springs.

It takes a little practice to get comfortable with this procedure. The same technique is used for starts and anytime traffic forces you into 2nd gear. So it is a valuable skill to learn. With a fresh trans (with new springs) and a little practice, you will not be missing the 2-3 upshift.

Hope this helps
Dave

[Keith Novak]

Having had this trouble in the past, and following Dave's recommendations I've become a lot more reliable at that shift and we have 2 places where it's necessary every lap at Portland. For the fast 3rd to 4th to avoid hitting 2nd , I switch my grip to the side of the knob with just my fingers wrapped around (not a full palm) and pull with the 1st 2 knuckles of my fingers. Haven't missed that shift since.

[KentCarter]

Also can be a sign of weak motor mounts. When you get the chassis twisted a bit and the motor under load, things ain't where you are used to them being.

Any time you start to miss lots of shifts, look at the nylon bushing on the end of the shifter.

[wreckerboy]

Echoing what Dave said about shifting, and what Kent said about the nylon bushings and the motor mounts. I had a marginal 250K trans in the car that was having similar issues on the 2-3 shift at Summit. Slowing down the shifting helped, as did replacing the bushings and ultimately the motor mounts. Both of these were interim fixes, however. Ultimately I replaced the trans when fifth gear became notchy and first gear became an occasional thing with a rebuilt unit from RP and the transmission-caused missed shift issues went away.

Something about these cars just kills the motor mounts - they were a frequent replacement item for the 160K that I drove the car on the street, and my 100K street 90 is on it's second set as well. I imagine that the '99s with all of their huge HP and torque must go through them even faster....

[Rob Burgoon]

Yep, get those pro motor mounts from mazdaspeed.

Also, I find that I tend to crack a synchro ring on 3rd gear every season or two. This makes it grind on every upshift, but you can just slam it past the grind... for a while.

[Joe Benoit]

We have the same issue at Sebring coming out of the hairpin from time to time. Like Dave says, open hand that shifter and let the springs do the work really solves the majority of the issues. MTL helped out in my transmission as well.

Joe

[davew]

Every idea above could be the culprit. But I would still bet on driver/trans.

[dstevens]

Pardon the thread jack but is the competition engine mount part #NAY1-39-040, "Rubber, ENG, MNT"? I've got a few seals and gaskets to get that aren't in the kit and I'm looking for more parts so I don't pay more in shipping than parts.

[davew]

Call the 800 number, the MazdaSpeed guys know the part number

[Go Time Racing]

My opinion is 2 fold. The nut behind the wheel and the trans is worn out.

The easy part is to rebuild the trans. Miata transmissions show internal wear at about 40,000 miles. That 130,000 mile trans is probably no better than what you have in the car. Everyone is amazed how much nicer a fresh trans is compared to the worn out unit. Think of it as a pair of old worn out tennis shoes. The're comfortable and seem to be just fine. Untill you buy a new pair and realise just how bad the old ones are.

The hard part is to change the driver! Inside the shifter body there are 2 springs that center the shifter in the 3-4 gate. These springs are not very strong to begin with, and are worse with age. It takes very little side force to move the shifter into the 1-2 or 5-R gates. If you are holding the shifter with your fist, you are going to over power those 2 springs. You have complete control of the shifter, and YOU have to hit 3rd gear perfectly, or you will miss the shift.

Let go of the shifter!!!! You need to push it forward, out of second, into neutral. Delay a split second for the 2 springs to center the shifter, then simply push forward into 3rd gear. I like to palm the shifter, catching the top of the knob in the joint between my 1st and 2nd fingers. This gives me a good feel for what the shifter is doing, but does not overpower the springs.

It takes a little practice to get comfortable with this procedure. The same technique is used for starts and anytime traffic forces you into 2nd gear. So it is a valuable skill to learn. With a fresh trans (with new springs) and a little practice, you will not be missing the 2-3 upshift.

Hope this helps
Dave

Hey Tom... are you taking notes?