'87 D21 L4N71B - Some Help Please!

[Bludacious]

Earlier this week I bought an '87 D21 for $950 with the Z24i & the L4N71B AOD transmission. I am the 2nd owner but the 1st one beat it like a hammer on a nail. Been lurking here absorbing info (first non v8 carbed american vehicle I've ever owned!) but now it's time for some questions. PO told me overdrive cuts in & out, on the test drive it didn't go, 2 hour drive home worked fine, grocery run last night not working. PO said he changed the fluid at some point but "couldn't figure out how to get the filter off". I found a great vid by an aussie on how to adjust bands, filter, solenoid locations, etc (vl commodore). 

 

What I do know:

The light on the dash goes on/off as expected

Overdrive worked under my ownership at least once without issue (pressing OD cancel dropped down a gear)

Trans doesn't slip but shifts a tad grumpy, I'd liken the shifts to a high mile 4l60e

There is a temperature switch in the pan responsible for enabling OD.

Battery was near-flatline & was driven home running off the alt, it has since been replaced with a fresh one.

I will be dropping the pan today for a fluid & filter change & adding a bottle of lubegard platinum.

I will be troubleshooting the solenoid today per the Mazda N4A-HL service instructions.

 

What I want to know:

How often is the solenoid itself at fault for this behavior? Should I suspect electrical faults as the prime culprit

How exactly do I remove this solenoid?

Is the solenoid N/O or N/C?

How to test the pan temp sensor? bake in the oven at 200?

Is the pan temp sensor even available anymore? I can't seem to find it.

Does the engine temp sensor lockout overdrive until coolant is hot? What I'm reading seems to say this is the case.

Is the solenoid made in a way that a machine shop could make me an adaptor to replace it with another solenoid that's actually obtainable? Best lead time I could find for a replacement was 2 weeks not including int'l shipping.

How can I tell if both the OD & TC lockup sol's are functioning properly? test light tapped into the harness while driving?

Will I damage the trans doing highway driving without the OD? Will the extra revs bother the z24?

[Bludacious]

Bump / update - changed the fluid / filter & retorqued the bands, trans seems pretty happy for 2XXk clocked. The only remaining issue is that any time I shut the truck off then start out again, I have to rev the motor above 2/3ish throttle before it goes into OD the very first time. Every shift from then on even from a complete stop happens as normal until I shut the motor off again. Will a bad TPS cause this? I'm almost 100% certain mine is bad due to the way it behaves under rapid acceleration.

[datzenmike]

The D21 Hardbody isn't a carburetor engine. It's Throttle body injection. Looks sort of like a carburetor but it isn't.

 

Never heard of a temperature sender in the L4N71B. Can't think of a reason for one.

 

The OD is just like the lower 3 gears. It won't shift until going fast enough as in out on the highway. This avoids it having to down shift, up shift, down shift with every small throttle input. The switch on the shifter just shuts it off if climbing a hill, driving into a strong head wind, passing or carrying a load. Using OD for these five is not a good idea.

 

I believe there is a solenoid for activating the locking torque converter. I don't think there is any need for an adjustment, it's just on or off.

 

The automatic shifts by sensing engine load. This is easily done by intake vacuum piped to the modulator valve. Heavy thottle = low vacuum. A leak would affect idle and the low vacuum would fool the automatic into thinking the throttle is floored and delay all up shifts.

 

I would never add anything to the ATF or engine oil. But that's just me.