Transmission Input sensor problem/ Questions 5R55e
 

I am very confused about a problem my truck is having. 1997 Ranger 4.0L V6 Automatic with a 5R55e automatic transmission.


Last week it started hitting hard into 2nd and sometimes a little hard into 3rd (more so 2nd). The Check engine light came on and it threw a P0715 code which from what I remember says something to the effect of "Turbine speed sensor "A" circuit". I was told this is the input speed sensor.


My problem is that I can see two sensors on the back, one looks like the output speed sensor and the other is the vehicle speed sensor (I believe). Up in the front of the transmission at about the 11 o'clock position (looking towards the front of the truck, drivers side) I can see another, what looks to me to be a sensor. It has a green plug going into it and I am assuming this is the input sensor. I got a part from the auto parts store but it does not look like what I can see so I am going to have a professional look at it. Problem is that even though I can see a sensor on the front top of the transmission, they tell me the sensor "might" be located inside the transmission.


Does anyone know if what I am seeing is indeed the sensor or is it located inside the transmission?????? HELP!!

Well, according to FORD, the sensor is located inside the transmission. That requires a whole transmission disassembly to get to. I am pretty upset about it.

Yes it is, and yes it does, but test it first

Go here: can it work in mine? | Ford Explorer and Ford Ranger Forums - Serious Explorations

In post #12 click on the image and copy it and print it
Then use an OHM meter to test wiring for TSS, turbine speed sensor

Could just be a bad connector, fingers crossed

It is located here inside trans: https://ww2-secure.justanswer.com/up...124735_tss.gif

I think I have enough room to get at that plug. So do I just unplug it, then put an ohm meter on pins 2 and 3 and see if the ohms are between 64 and 126 ohms of resistance? Is that the check?

Yes, and also look at general condition of connectors, see if water has got inside

Ok. I have 75.2 ohms and it looks dry and clean

You have a 4R55E in a 1997 Ranger 4.0l, just FYI

Then wiring to PCM(computer) is the issue

The TSS grey/red wire goes to pin 91 on the PCM, if you want to test for continuity

Wiring here

From my VIN#, the dealer says I have a 5R55E. Does that change anything?

No, not really, but you do have a later model 1997, 5R55E wasn't officially used with the 4.0l Rangers until 1998 model year

4R is a 4 speed
5R is a 5 speed BUT(big but)...........it is the same transmission

4R has these gear ratios
1st: 2.47
2nd: 1.47
3rd: 1.00
4th, OD: 0.75

There is a big gap between 1st and 2nd, so 1st had to wind up pretty high before computer changed to 2nd gear so engine didn't lug

One of the engineers at Ford came up with a clever idea since the 4R had full computer control over gear changes
"Why don't we engage OverDrive(.75 ratio) while still in 1st"
1st(2.47) x 4th(.75) = 1.85 ratio approx. there are mechanical exchanges that make it closer to 1.87 ratio

5R has these gear ratios
1st: 2.47
2nd: 1.87 <<<< they added a faux 2nd gear to get a 5 speed from 4 speed transmission
3rd: 1.47
4th: 1.00
5th: 0.75

Very cool

So no, there are no major internal differences between 4R and 5R it is all done thru computer control

What should I look at next?

TSS sensor reads like it is OK, so now check the wires from the TSS sensor to the PCM(computer)