The local AutoZone read the OBD codes on my 97 4X4 5.4 as DTC PO705, Trans Range Sensor Circuit Malfunction, (PRDNL Input), and PO708, Trans Range Sensor Circuit High Output.

About 10% of the time this tranny shifts extremely hard into 1 and 2, less hard into 3, sorta seems like it's in Lo range. A fluid change made the problem disappear for a few days.

Where do I start to solve this problem ? Is a part needed that is accessible without going inside the tranny, and can a guy of average ability do it without disaster ?

Thanks for any suggestions. This rascal has 155k on the clock by the way. Fluid was changed 3 times in it's life.

Pyzon

 

The range sensor is the sensor on the side of the transmission where the linkage connects.
Do you have any linkage problems in the column?
Alan

 

No, dirtyd0g, nothing that has been the least bit obvious. Any suggestions ?

Thanks.

 

A shop with a scanner can test the functions of the MLPS (range sensor) but for the expense it would be cheaper to just replace it than to test it.
It needs to be properly aligned upon installation. I have a tool for it but you can do it by eye . It has marks on it that you line up with the transmission in neutral.
Hope this helps.
Alan

 

Thanks, dirtyd0g,

Just so I understand clearly, the range sensor can be replaced and the only real installation issue is the proper alignment of the sensor with the selector in the neutral position ?

Sounds too easy, but I'll give it a go. The alignment tool you refer to is probably a Ford dealership service tool that independent shops would not likely have, correct ?

thanks a ton.

 

The range sensor is easy to replace all you need is a 15mm wrench and a 8 mm wrench.
Aligning it is pretty simple too once you bolt it on leave the 2 8mm bolts loose and put the trans in neutral. You will see the alignment marks.
Alan

 

OK, sounds easy enough.

I suppose that part is only available at a dealer ? I think I'll give NAPA a try first.

Thanks for the help.

Pyzon

 

Napa might have it. I personally am a firm believer in OE electronics.
Alan

 

Dirtyd0g-

Thanks for the good advice and installation tips. $48 part and 15 minute install make this problem history !!

Keep up the good work, friend.

Pyzon

 

Your welcome. Glad you got it taken care of.
Alan