Relationship between engine rpm, ISS and OSS readings

[Swampy1970]

I was looking at the data from the PCM for engine rpm, ISS and OSS and wondered if there was a formula to check that the correlation between the three was correct in different gears and different engine rpm.

In 3rd gear (2 position on selector) ISS and OSS readings seem similar.

When in D - OSS always reads about 1000 to 1500 rpm higher.

What's the "good word" on this?

Maybe this info is hidden deep in the depths of the factory service manual. I obviously need to read it more as I just figured out how to read the effin' trans dipstick properly after replacing the valve body and testing half the sensors related to the trans and their wiring...

 

[imp]

In 3rd gear (2 position on selector) ISS and OSS readings seem similar. Bit more info needed, like, what year and which transmission are we talking about? However, assuming 3rd. gear to be "high gear", that is, no reduction due to gear ratios, the Input Shaft and Output Shaft speeds SHOULD be identical, assuming no slippage is present in holding devices (clutches).

When in D - OSS always reads about 1000 to 1500 rpm higher. Given that the trans. is in O/D gear, the Output Shaft speed SHOULD always be higher than the Input Shaft speed....that's why it's called Overdrive, yes?

What's the "good word" on this?

Maybe this info is hidden deep in the depths of the factory service manual. I obviously need to read it more as I just figured out how to read the effin' trans dipstick properly after replacing the valve body and testing half the sensors related to the trans and their wiring... If it has a dispstick, it is not one of the newer transmission applications, right? imp

 

[Swampy1970]

It's for a 5r55e in a 01 Sport Trac.

Supposedly a 5 speed...
... but it would seem that my PCM never sends the trans the request for 1st gear. Unless Autoenginuity lies...