Anyone know anything about Mazda Miata auto trans?

[zman]

Gentlemen, A girl I know asked me to look at her Mazda Miata 91` model. The trans just quit, When placing it into gear the idle drops a little like it is engaging but giving it gas it just rock a little forward or reverse depending on gear selection but giving it gas it just slips.
I`m thinking it is pull it time, tourque converter pump maybe but since I am unfammiliar with these cars is there anything else to check before I pull it,maybe some vacuum operated trans gizmo or other outside device?
Fluid checks full, I noticed synthetic trans fluid bottle in the trunk, I dont know if it was all synthetic or she mixed it with regular but I wouldnt think that is a problem. Fluid may be over full, I need to check again once the battery is charged and car started.
Thanks.

 

[joedrum]

clueless

 

[zman]

Thanks Joe, It was a long shot asking here but you never know and I leave no stone unturned.
Doing some googling on it now and I guess there is some kind of valve of some kind that can cause it but still not simple and may not be the problem. Been inside automatics in the past but that was Turbo/powerglides,tourque flite 727`s,C4-6`s and the like, newer and forign types are a little different.

 

[dan filipi]

Hold out for Aapple to respond. He's a trans tech.

 

[AApple]

Should be an L4N71B trans...old Jatco design used for years in Mazdas and Nissans/Datsuns, but they worked pretty well. Does have a vacuum modulator, but that only controls the pressure/timing of the shifts. The only problem with a modulator is if the diaphragm tears, it'll suck the trans fluid up into the intake, and burn it out the exhaust. This can run the trans low on fluid...causing it to burn the clutches. Need to ask her a few more questions...
I'm assuming it just up and stopped moving, with no warning, or has she been having some issues for a while? If the rpms go down, and it feels like it's trying to engage, the pump is working.
What does the fluid look/smell like? Mixing synthetic with dino isn't a problem. Using some kind of snake oil is....find out if it has had anything other than trans fluid put in it.
If the fluid smells /looks burnt.....it is.
Not really much externally could cause it....if the shift linkage is all connected, then it kinda sort hasta be an internal issue. Out she comes.... :builder: :crying:

 

[zman]

AApple » Mon Oct 28, 2013 7:27 pm[/url]":3ctxdb1g]
Should be an L4N71B trans...old Jatco design used for years in Mazdas and Nissans/Datsuns, but they worked pretty well. Does have a vacuum modulator, but that only controls the pressure/timing of the shifts. The only problem with a modulator is if the diaphragm tears, it'll suck the trans fluid up into the intake, and burn it out the exhaust. This can run the trans low on fluid...causing it to burn the clutches. Need to ask her a few more questions...
I'm assuming it just up and stopped moving, with no warning, or has she been having some issues for a while? If the rpms go down, and it feels like it's trying to engage, the pump is working.
What does the fluid look/smell like? Mixing synthetic with dino isn't a problem. Using some kind of snake oil is....find out if it has had anything other than trans fluid put in it.
If the fluid smells /looks burnt.....it is.
Not really much externally could cause it....if the shift linkage is all connected, then it kinda sort hasta be an internal issue. Out she comes.... :builder: :crying:

Good info Joel, Thanks.
That`s about all I need to know right there. I`ll ask about the fluid but i`m thinking she probably added that quart when it stared acting up but it wasnt low on fluid like she thought ,thats why it looks over full on the dip stick..It is.
Fluid didnt smell burnt but I just pulled the stick and got maybe two feet from it. I`ll check up close later this morning and check the color and see if motor oil wasnt added by mistake. I`m thinking either way a fluid change wouldnt fix it at this stage.
Does that sound right?

 

[AApple]

Yeah...if it won't move at all, changing the fluid isn't gunna do anything but waste fluid. Find out if it just quit suddenly, or if it's been having problems for a while, and finally died. It's possible that if it was something that just happened, it might have stripped the input shaft splines....fairly common on those with some mileage.

 

[dan filipi]

Could the filter be clogged?

 

[joedrum]

hmm yes ..could be ...

 

[AApple]

dan filipi » Tue Oct 29, 2013 7:47 am[/url]":3i3akn54]
Could the filter be clogged?

With WHAT? Transmission parts? Could be.... :whistling:
:hihihi:
Metal screen type filter. If it's clogged up enough to keep it from moving, the trans is trashed anyway...normal wear/tear will not clog a filter.....excessive wear/metal and clutch damage will. :crying:

 

[joedrum]

i bow down to the transinformer :headscratch: :hihihi:

 

[dan filipi]

AApple » Tue Oct 29, 2013 9:26 am[/url]":9iegbqsa]

dan filipi » Tue Oct 29, 2013 7:47 am[/url]":9iegbqsa]
Could the filter be clogged?

With WHAT? Transmission parts? Could be.... :whistling:
:hihihi:
Metal screen type filter. If it's clogged up enough to keep it from moving, the trans is trashed anyway...normal wear/tear will not clog a filter.....excessive wear/metal and clutch damage will. :crying:

I agree but I'm pretty sure if we'd had the filter and fluid changed in our burb of 50k miles we could have put off a rebuild.
Just suggesting in a money pinch a filter change may get it going.

 

[zman]

It may be fixed..I added a quart of fluid, was not reading on the dipstck at all when idling in park, A quart put it halfway to the add mark and I`ll see if she wants a full trans service before I add more.
No leaks that I can see at the moment, drove around the block..Shifted late and hard like a Mazda RX3 I once owned only slower without the Wankel rotary.
She went out and bought a new car when it broke down 6 months ago and just recently asked me to fix it up and sell it.
What do you think would be fair for fixing it up? She offered to split the sale price with me but it seems too generous..Am I wrong?
Here`s what I have done and need to do.
3 stage machine buff the paint.
Deep clean the inside(she is a smoker)
Fix both side windows, they dont roll down easy.
Fix misc. broken/loose interior trim and vacuum out and clean fabric seats.
Deep clean and really scrub the aluminum wheels, they are near black but should be silver.
Fix exhaust leak at manifold(loose bolts) Take shield off and re install.
Thanks.

 

[AApple]

zman » Mon Oct 28, 2013 4:04 pm[/url]":3j3893k9]
Gentlemen, A girl I know asked me to look at her Mazda Miata 91` model. The trans just quit, When placing it into gear the idle drops a little like it is engaging but giving it gas it just rock a little forward or reverse depending on gear selection but giving it gas it just slips.
I`m thinking it is pull it time, tourque converter pump maybe but since I am unfammiliar with these cars is there anything else to check before I pull it,maybe some vacuum operated trans gizmo or other outside device?
Fluid checks full, I noticed synthetic trans fluid bottle in the trunk, I dont know if it was all synthetic or she mixed it with regular but I wouldnt think that is a problem. Fluid may be over full, I need to check again once the battery is charged and car started.
Thanks.

:headscratch: :headscratch: :headscratch: oh2: :smilie_happy:
Hope that's all it was, but...if it was that low, where's it leaking? If you don't see any obvious external leakage, pull the vacuum line off of the modulator valve. If fluid runs out, the mod valve is ruptured.

 

[slabghost]

Top off the trans and fix it up. Splitting the sale is a fair price. Consider your labors and time.

 

[Ansimp]

+1 on the fair price

 

[zman]

Good advice ..Thanks everyone.
Thanks Joel, My happiness that it was working with no internal damage was soon left last night and was replaced with where the fluid went.
I`ll get it up in the air and look at the modulator,pan bolts,shaft seals and see.