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I've recently replaced my worn NA6 gearbox with a completely reconditioned one. Though it does feel smoother, the gearshift is still quite notchy and does not feel really any different to what it did in the old box.

My question is: Has anyone tried rebuilding their shifter? And if so, have the results been good?

I have seen rebuild kits on eBay and have been tempted, but they are upwards of $90 from Rosenthal Mazda in the USA.

Anyone know of a cheaper method? It just seems to be a nylon cup, some nylon washers and a couple of thin metal washers.

It wont be that it will be the synchros and the detents.

Dann

Mania used to sell the white plastic cup/bush. There was also a Beatrush brass cup/bush, but if the current one is not worn or broken then it probably won't make much difference.

If you don't mind the feel, cheaper to buy a short shifter kit, or buy the basic rebuild kit (without boots) $39:
http://www.planet-miata.com/index.php?s ... em&idn=214

Or

93_Clubman wrote:Good results for forumites from using Nulon full synthetic 75W-90:
http://www.nulon.com.au/products/Gear_a ... a_kZ5w2X_g

to which they add Nulon G70 additive:
http://www.nulon.com.au/products/Specia ... Treatment/

Then again, could be the age of the GB.

As Dann said, it will probably be the detent springs. I purposely build my gearboxes with uprated and matched springs, gear and shaft float shimmed to the tighter end of the tolerance spectrum etc., so it won't pop out of gear down the track. I know Needham and other gearbox builders do too.

A tight gearbox is a good gearbox.

The shifter rebuild gives the shift 'action' a more positive feel but like others have said will not solve the notchiness. The link below is a TSB that relates to the common 2nd gear issue.

http://www.miata.net/garage/tsb/s004_92.html

I wonder what the cost would be to have this done......

wassup wrote:I wonder what the cost would be to have this done......

Forget who it was, but a forumite had an MX5 GB rebuilt in the last couple of years & mentioned it cost around $2.5k.

I have perviously rebuilt the shifter. It did make some difference, however the biggest change came from fitting a heavier 'knob' I picked up a 2nd hand one from Allmaz wreckers in Clayton. It weighs in at a portly 320 grams.

You are welcome to try my knob to see if it makes any difference.

J.

On the weekend I lost 1st and 2nd gear and reverse. Couldn't get gears no matter how much a lent on the stick. Would the suggestions above solve my problem. I'm pretty confident the clutch is fine. It does have a short shifter and the gearbox was reconditioned by previous owner not long ago.
Any suggestions or comments?

Regards - John

No bang, nothing. One minute it's fine the next very difficult to engage 1st then unable to engage 1-2-R.

93_Clubman wrote:

wassup wrote:I wonder what the cost would be to have this done......

Forget who it was, but a forumite had an MX5 GB rebuilt in the last couple of years & mentioned it cost around $2.5k.

$2.5k!!!!

buy a six speed

wassup wrote:

93_Clubman wrote:

wassup wrote:I wonder what the cost would be to have this done......

Forget who it was, but a forumite had an MX5 GB rebuilt in the last couple of years & mentioned it cost around $2.5k.

$2.5k!!!!

Yeah, it was last year & closer to $2.25k.

j.a#9 wrote:On the weekend I lost 1st and 2nd gear and reverse. Couldn't get gears no matter how much a lent on the stick. I'm pretty confident the clutch is fine.

j.a#9 wrote:No bang, nothing. One minute it's fine the next very difficult to engage 1st then unable to engage 1-2-R.

First thing is to confirm the slave cylinder isn't leaking, as these commonly go on NA6 & NA8. Check from underneath the car that the rubber boot around the end of the slave cylinder & push rod don't contain brake fluid. If slave ok then confirm master cylinder isn't leaking.

Sorry for hi jacking,

but quick question on the subject; if my shifter sometimes wont go into 2nd when I downshift from 3rd, no crunching and it usually goes in fine when I rev match.. what could this be?

(NA6 5 speed, new exceedy clutch & lightened fly, entire shifter can pivot slightly when turned on the spot).

Worn synchro.

Or (more likely, and cheaper) worn shifter bush thingy. (the white nylon cup at the base of the shifter)