New to P5 Auto Tranny

[Mikeyman64]

Hey there,

I just purchased 2 "beater" P5s from a local Mazda parts place. I got them both for a steal, and my goal was to take good parts off of one (has some racing heart MP3 wheels and a Team Moon exhaust) and get the other one driving to sell for cheap or give to a friend who really needs a car.

The one I want to get rid of has an automatic transmission. It's a 2003, so it has the "shifter" option. She has about 130k miles on the odo.

The problem I am having is it shifts fairly hard, especially out of 1st, and it will often take a while to do so. Also, sometimes 4th gear acts like neutral. If the car naturally shifts to 4th, I rev the engine and it revs, but zero power transfered to the half-shafts. I have to pop it into "manumatic" and shift down in order to get power back. This is all tested after letting the car warm up for about 5-minutes. I try to do all my testing when the fluids are moving properly.

I am new to ATs, but I know that sometimes they act odd when they are under/over filled with ATF. I checked the fluid (cold engine, flat, cleaned dip stick and rechecked) and it was WAY over the hot engine temp mark. So it appears that it has been very much overfilled.

I am going to go ahead and order a tranny-pan gasket/filter and I just bought some ATF MV. But is there anything else I need to check or replace? Again, I own 4 cars and a motorcycle, and all of them are manuals... So apart form casual car work and basic knowledge, I am a "noob" when it comes to actual automatic transmission.

-Thanks!

 

[pcb]

The oil level is supposed to be checked with the engine hot and at idle.

 

[pcb]

One thing I remember about the automatic transmission is that if the oil has not been changed in a long time or maybe has never been changed the transmission can go all screwy after an oil change because the transmission adjusted to the old oil.

Some guys who had to work on their transmission would save the old oil and reuse it.

Apparently, the best way to do it is to drain off a quart of old oil and replace it with a quart of new oil.

Then run it for a while for the transmission to get used to it then repeat the drain, fill, process a bunch of times.

You'll never get a complete flush but your transmission may start working operating better without the issues of a complete flush.

 

[Mikeyman64]

One thing I remember about the automatic transmission is that if the oil has not been changed in a long time or maybe has never been changed the transmission can go all screwy after an oil change because the transmission adjusted to the old oil.

Some guys who had to work on their transmission would save the old oil and reuse it.

Apparently, the best way to do it is to drain off a quart of old oil and replace it with a quart of new oil.

Then run it for a while for the transmission to get used to it then repeat the drain, fill, process a bunch of times.

You'll never get a complete flush but your transmission may start working operating better without the issues of a complete flush.

Excellent advice. I appreciate it.

Yeah, it looks like even if I check the atf when the engine was cold on a chilly day (it's about 55F here today), the fluid would be lower on the dip stick. And on this P5 it was WAY over both markers. The entire stick is wet. So I'm thinking it was badly overfilled.

I'll plan to drain the oil, save it, replace the filter, refill with the old oil to the appropriate level, then start your recommended process.

I'll update as o have time to work on it.

 

[pcb]

Was the engine running?
That changed the level in a big way.

Oh, ... Strain your old oil through a coffee filter.

 

[Mikeyman64]

Was the engine running?
That changed the level in a big way.

Oh, ... Strain your old oil through a coffee filter.

No, engine was off.

Ok. I'll grab some xl coffee filters. Is that just to help filter out any larger metal shavings and whatnot?

 

[pcb]

Engine needs to be running...

The fluid level drops significantly when the fluid is flowing.


The filter catches any crap before you put it back in your transmission.

 

[Mikeyman64]

Just dumped the transmission oil and changed the filter and pan gasket. I refilled with some old oil and some new.

Problems pretty much persist. It jerks into, 2nd, and 1st and 4th slip pretty much 100%, e.g. they feel like neutral.

Is this something that may go away as it "gets used to" the new ATF? Or is there likely a deeper issue here? I have the shop manual, so I might go ahead and start some of the easier diagnostics, like solenoid resistance values.

Or I might just trash it and convert it to a manual with the old tranny from my personal P5....

 

[pcb]

My car is a 5-speed manual.

I know almost nothing about an automatic.

I bought my car only because it had a manual transmission.

 

[Spencer_P]

Usually the only time new fluid will cause problems is when the old fluid is black or even burnt, in which case your tranny was already on it's way out. I have heard of people bringing a "shot" tranny back after multiple drain and refills. How'd your old fluid look? Smell?

 

[Mikeyman64]

Usually the only time new fluid will cause problems is when the old fluid is black or even burnt, in which case your tranny was already on it's way out. I have heard of people bringing a "shot" tranny back after multiple drain and refills. How'd your old fluid look? Smell?

Really bad. It was quite black and had some metallic bits in it.

Based on the symptoms, I'm going to try and clean out and mess with the solenoids. Connector pin B and F did not click when I attached 12V across them and ground, so I'm assuming they are either toast, or possibly stuck due to the nasty fluid.

If that doesn't work, I will honestly likely just swap my old 5spd into it. The solenoids are expensive, and my tranny might very well have other issues, so I don't know if it's worth the risk of replacing them.

 

[i12drivemyMP5]

there are shift sensors in the console by stick and there is also a turbine speed sensor on top of tranny. not sure either of those would cause issues you're having or whether those would be torque converter and or valve body issues. Talk to a transmission shop about it and see if that leads anywhere. mine is sportronic and still working fine. Not better than stick but better than plain auto.......

 

[Mikeyman64]

there are shift sensors in the console by stick and there is also a turbine speed sensor on top of tranny. not sure either of those would cause issues you're having or whether those would be torque converter and or valve body issues. Talk to a transmission shop about it and see if that leads anywhere. mine is sportronic and still working fine. Not better than stick but better than plain auto.......

This one is a sportronic as well. The only time it "slips" in 1st is when it's in shifter mode, or in 4th in either mode.

I've zoned in on a few of the shifter solenoids for two reasons: 1, the fluid was really dirty and 2, I tested each one in the transmission and while each resistance value is in spec, only 3 of 3 clicked when supplying 12 volts to the associated pins. I'm going to pull them and clean and test them out of the car and if I can't get the other 3 to click, I'll buy new ones and see if that helps the issue.

I just hope the car wasn't driven too long with this nasty fluid to the point the clutch plates have worn down completely. I'll check those other things as well. Thanks!

EDIT: I pulled each solenoid and tested them all. Resistances were still good, but a lot of them did not "click" very well when applying 12V (I checked the wiring for polarity). Some would even buzz loudly when. I tried cleaning them out with MAF cleaner, and some got a little better, but still not as nice as I would expect. I'm getting a price quote for all 6 solenoids in the hopes that it will at least make some of the problems go away.

EDIT 2: Replaced each solenoid, and still having the same issue. The shift from 2 to 3rd got a little smoother, but I still 100% slip in 1st and 4th. I guess a rebuild is in order. I'm not sure what else to check.

 

[pcb]

It may take some time for everything to adjust.
For both the ECU and the mechanical parts in the transmission.

If it's still driveable, I'd keep driving it and give it some time.
A long hard-working road trip may help.
Put it through its paces.
Get it nice and warmed up.
The parts may need to be "flushed out" by the fresh oil.

Perhaps resetting the ECU? (disconnect the battery for ten minutes)

 

[Mikeyman64]

It may take some time for everything to adjust.
For both the ECU and the mechanical parts in the transmission.

If it's still driveable, I'd keep driving it and give it some time.
A long hard-working road trip may help.
Put it through its paces.
Get it nice and warmed up.
The parts may need to be "flushed out" by the fresh oil.

Perhaps resetting the ECU? (disconnect the battery for ten minutes)

Great tips. I'll definitely try these before dumping a hunch of money into it.

 

[pcb]

The other guys' had to do multiple flushes for things to sort themselves out.

If you reset your ECU and notice any change, you know that something is changing while the ECU is learning.

 

[pcb]

Keep in mind that if you disconnect your battery, your idle may be crap while your ECU relearns how to idle the car.
(it takes about 100 miles of driving to sort itself out).


I'm not sure but I think the ECU "learns" how to shift an automatic transmission as well.


If there is any change in the transmission after a reset, you know it's a communication issue between the ECU and transmission not so much a failed transmission.

 

[Mikeyman64]

So sorry to bump this thread. I just wanted to give a final follow-up to the project.

So the solenoids never did end up working. I tool the car to a transmission shop and they quoted me $2400 to overhaul the tranny.

So I ended up doing an auto/manual conversion, and I am almost done! The most difficult part was rewiring the plugs for the transmission sensors and instrument cluster. I also have to wire some resistors to the shift solenoid wires to trick the CEL. Other than that, the swap went perfectly. I got the backup light working and the speedo.

I'm giving/selling it to a kid who needs a car, so once I get it inspected for a rebuild title and out of my garage, it's on to working on my next project.

EDIT: I also now have all 7 perfectly working, new shift solenoids to sell. And a core auto tranny with possibly working solenoids...

 

[pcb]

Thanks for posting.
I'm curious as to how the swap works.


I remember that for the swap, the clutch switch needs to connected to the ECU.
The ECU needs to know to go to idle when the clutch is pressed and the cruise control needs to know as well so it can turn off.


The neutral switch needs to be connected as well.









There is also a starter interlock switch on the clutch so you can't start the car without the clutch pushed.





I was under the impression that there is just one ECU for both the automatic and manual transmission and the ECU somehow recognizes the inputs and adjusts accordingly.

So, are you "tricking" your ECU into thinking it's running an automatic?

I thought that you didn't need to have to trick the ECU. It just switches to running a manual transmission?

 

[Mikeyman64]

It is the same ECU. It's only the wiring harness and instrument cluster that are auto specific. The bulk of the harness (don't remember the part numbers off hand) that run under the dash is the same. It just gets different running to the cluster and out to the tranny. But I was able to basically disconnect and insulate the unneeded wires from the far left two cluster plugs to get the AT light to stop flashing, and then wire the clutch pedal switch directly to the starter switch. The backup lights were easy to trace with the wiring manual and wire to the backup switch, and the neutral switch was the same, easy to trace with the manual.

All I have left to do is try and make some resistor packets to match the resistances of the solenoids to get the CEL to go off.

The mechanical conversion was pretty straight forward. Just needed a new brake pedal as well since the auto's is too wide and it's hard to hit the clutch without tapping it.

I can post a complete re-wiring guide here if you all think that would be beneficial to anyone.