Received 0 Likes on 0 Posts 4r44e OD off won't move forward or reverse

[gezitz57]

I have 1999 Mazda B2500 that I rebuilt the transmission about 36K miles ago. Worked flawlessly until the transmission cooler line in the radiator cracked and the transmission was filled with coolant. Tore it back down and rebuilt it again to get all the coolant out and all worked fine. While I was in there I replaced the solenoid wiring harness because the wiring insulation was deteriorating. Recently the ABS light started coming on all the time. Drives and shifts fine with the OD "on", but if you click the OD "off" it will not move forward or reverse. It acts like one of the solenoids is applying pressure and locking the transmission up. Turn the OD back on and it drives fine. I replaced the axle ABS sensor but this did nothing. I also checked the resistance of all the solenoids and all are within specification. Could it be the ECU? I don't want to just buy one if its not needed. Any help will be greatly appreciated as I am stumped.

 

[Dirtman]

Sounds to me like the wiring to the solenoids is wrong and instead of turning off solenoid C when you hit the OD-Off button it's turning off solenoid A.

 

[gezitz57]

Thanks for the reply Dirtman ! The new solenoid wiring harness only allows you to make the connections in order so I don't see how they can be connected wrong as the wiring loom has a plastic strip keeping them in order. I did a lot of research on the solenoids and what you said makes sense. Now the question is where to go from here. Given the solenoids are controlled by the ECU do you think this could be the issue?

 

[snoranger]

Its a new harness, correct? Is it possible that the nearness wasn’t built correctly? You may have a pin in the wrong spot or bent over touching another terminal in the connector.

 

[Dirtman]

That's what I was eluding too, the new harness itself may be wired wrong, not you physically plugging it in wrong cause as you noticed, that's impossible.

 

[gezitz57]

Its a brand new wiring harness. Good point. I will double check it as soon as the rain lets up.

 

[Dirtman]

Its a brand new wiring harness. Good point. I will double check it as soon as the rain lets up.

It's not even remotely uncommon for brand new parts, especially electronics to be bad out of the box.

I mean I can't say that's for sure the problem, but I can't see any other reason the overdrive button would cause problems unless it's turning off the wrong solenoid.

 

[Robertmangrum.rm]

I use a lot of pre made harnesses and have to say 1 out of 10 are pinned wrong. Normally reverse like they had it upside down when they pushed the wire into the connector. Since the connector can only be plugged in one way all wires would be reversed

 

[gezitz57]

I pulled the harness and checked the wiring against the factory wiring diagram and all is correct.

 

[gezitz57]

Anyone have any further thoughts on this as I am searching to see if this has happened to anyone else.

 

[gezitz57]

OK I did further testing now that the rain has ended and want to add some detail of my findings.
All solenoids resistance check with in factory specs for resistance. The new solenoid wiring harness is wired correctly (matched against wiring diagram and old harness.)
If I put the trans in manual 1st it acts like the brakes are on
If I put the trans in manual 2nd it acts like the brakes are on
If I put in drive (with OD on) it drives and shifts normal, reverse works and the ABS light comes on above about 10mph
If I turn OD off it acts like the brakes are on (OD light doesn't come on)

I have a spare PCM and installed it and the results are exactly the same except for if I turn OD off it acts like the brakes are on (OD light does turn on), the light coming on is the only difference.

So it does not appear to be a PCM problem. Could a solenoid be stuck or maybe a spool valve in the valve body be stuck?

 

[Dirtman]

Remove transmission. Rebuild transmission.

 

[gezitz57]

Can you elaborate on your response? If the transmission shifting is controlled electronically and it works fine with the OD on in drive doesn't this rule out a mechanical problem that wouldrequire a rebuild? Couldn't it be in the valve body? Or am I missing something here?

 

[gezitz57]

Did another resistance test on the solenoids. Found that the EPC was now out of spec, replaced it with a new one that has the red screen (like the original). Tested it and still no improvement, then received P1740 error code and OD light started flashing. This is the first time receieving an error code. Replaced the TCC solenoid, error code P1740 went away, and still the same symptoms again with OD light flashing.

I also double checked on manual 1st and 2nd gear functionality with OD turned on and with OD turned off. It acts the same, like the brakes are on. Any thoughts?

I did a comprehensive review of how the clutches are applied (using Sonnax's info) and it does not appear to be a mechanical problem.. I also did a comprehensive review of the solenoid apply chart (Sonnax) and the only area I am not sure of is the CCS solenoid and how it functions in relationship to the coast clutch itself... more research coming..

 

[bobbywalter]

The speed sensors correct not switched or pinched.? Did you pinch wires between engine and transmission?