3barboost

iTrader: (1)

Help please

So my 91 na which I bought as a non runner is stuck in 3rd (based on lever position and I can barely just pull off in 3rd if it was 5th I dont think I could pull off) clutch works as normal but just cant change gears

I have tried the detent spring and ball removal on all the detents i could get to - no luck

I have tried the reverse light switch jiggle - no luck

I have tracked the problem down to something more serious than those simple fixes - its either in the box itself or the shift rod from the turret

The previous monkey that worked on the car clearly forced the shifter against the turret hole on the body as they clearly removed and installed the engine and gearbox as a unit - with leaving the shifter in place - so something has been forced - plenty scratches and nicks and obviously excess force used

The innards of the turret wont disassemble now - I have got the box out the car and the turret halfway disassembled - but I cant get the roll pin out as its stuck in gear and there isnt enough space on the other side of the sifter pivot block for the roll pin to knock through - I have knocked it halfway through and its up against the turret casing on the other side - any ideas how to remove this half knocked through roll pin ? thats now butted against the turret housing.

I have tried screwing a self tapping screw in and pulling on that - no luck

I am thinking of taking a small drill all the way through the roll pin and drilling a small hole say 2mm all the way through and popping out the other side of the turret and then drilling a bigger hole back in to then knock the roll pin through, and then plug the hole with jb weld or similiar

Anyone have any other ideas before I swiss cheese this turret ?

Parts are scarce for Miata transmission in my part of the world - any help and advise welcomed

Miater

Sounds like a solid plan.

If you have the transmission out of the car, take some pics of the situation. The turret isn't the only problem here. Your going to have to take the whole trans apart and service the fork or rod, so might aswell take it apart now. I don't remember if the shift lever keeps that from happening but sounds like you should start from the other end before drilling holes. Not that I think a small hole filled back in will be a bother but you should be able to free it without drilling.

3barboost

iTrader: (1)

Hi

thanks for the advice

yip the box is out and on the floor - drilling through and slowly enlarging the hole until the split pin popped out worked well - but I wouldnt like to do it again

the turret is off and free - the rod going into the gearbox seems slack and wobbly and its still in 3rd gear - the rod from turret to box moves about 3inches in and out and about 120degrees in rotation so something loose / broken inside the box itself

I am going to wind google up abit to find a gearbox manual and see whats next - I hope nothings broken broken and its something thats slipped out

heres a pic of the hole drilled to show how far off the split pin was from coming out the normal way
[IMG][/IMG]

matthewdesigns

iTrader: (8)

Here's a link to engine/body/chassis catalogs from Mazdaspeed.
MAZDASPEED MOTORSPORTS DEVELOPMENT - Miata Parts Catalogs and Collision Guides 1990-2002

There are exploded views of transmissions within the appropriate PDFs which ought to help you out. With that much play in the shift rail and trauma to the car from it's prior removal I'd guess broken 3-4 fork, but could potentially be that the rollpin backed out of the fork/rail, or less likely that the rail itself if broken. Post pics once you get it apart.

If you find an actual gearbox manual please post a link!

3barboost

iTrader: (1)

ok good and bad news !

bad news - no gearbox workshop / service / overhaul manual found anywhere

good news - the actuating rod from the turret had got jammed in the fist of fingers (dont know proper name) that actually engage the shift forks
just re aligned them (and had the wife hold it all together as I slipped the extension housing on)
nothing bent
nothing broken just completely out of alignment

gearbox is back together and shifts beautifully - i cleaned and polished the moving parts in the turret and lubed it up with cv grease and the shift feel with the box on the floor is awesome - so its going back in in the morning

so this gearbox bullet is dodged means more money for bigger turbo

thanks for the help

Kinavo

iTrader: (1)

what coincidence. Mine just got stuck in fourth gear.

So ultimately you were able to fix the problem with just removing the turret? I am a little confused about the hole that you drilled. Was it necessary for the fix?

3barboost

iTrader: (1)

I had to drill a hole in the turret right through the roll pin and then use that 2mm hole as a pilot hole to make a 5mm hole from the other side so i could knock the roll pin all the way out - you cant dissassemble the turret until the roll pin is knocked through - once i got the turret off my shift rod from turret to box was srill stuck - i pulled the back case off and found the "fingers" jammed two minutes later was wiping oil off to apply sealant and reassembling - once the shifter turret was off it was like 10minutes to take back housing off unjam and reassemble and all was good box shifts like new at the moment

With yours in 4th it may be possible to knock the roll pin out directly

But pull the box and remove the rear housing line up the 3 fingers in neutral and slot the turret actuator in and reassemble

Knowing what i now know i wouldnt dissasemble the turret unless there were broken pieces in it i would just pull the rear housing off and the turret will unjam when you unjam the fingers

By fingers i mean these guys

3barboost

iTrader: (1)

[IMG][/IMG]

matthewdesigns

iTrader: (8)

Glad to see you got this resolved without pulling the housing apart! Thanks for the update.