ISS transmissions

[turbo_bu]

Does anyone know when the intermediate speed sensor (ISS) started to be added to the 4 speed autos? Either 4L60/65/70E etc... or the 4L80/85E's? There is probably a good chance it wasn't done all at once, but was curious as to when it started. Car information is nice, but would also like to know when the trucks started getting them.

I'm trying to better understand what years of ECM / TCM combinations are better than others. I think that I read for AFM (active fuel management) to work, you had to have a transmission that had an ISS. Not sure if VVT also required it or not too.

[joecar]

4L80E and 4L85E always had the ISS (input speed sensor).

4L70E and later 4L65E also have it.

4L60E and early 4L65E did not have it.

(I can't tell you which years).


I don't think ISS is a requirement for AFM, and I know VVT is not required for AFM... but I don't know the details.

[turbo_bu]

joecar,

Thanks for the reply. I figured that this would be a hard bit of data to decipher out. Kinda suprised that the 4L80E's always had one... I guess this might lead to another question, maybe I am just confused about what's inside the transmissions these days.

Is there just an Input Speed Sensor and an Output Speed Sensor, or is there an Intermediate Shaft Speed Sensor too? Maybe the Intermediate Shaft Speed Sensor is just in the 6 speeds?

[joecar]

4L80E cross section shows ISS and OSS (they're shown on top of the case by drafting convention, but they're actually on the side of the case):




4L60E cross section shows OSS (being VSS) is read from the reluctor on the output shaft:




The ISS on the 4L65E/70E is read from an extra set of dog teeth on the input shaft (at the pump/stator support).


I'm not sure about the 6L80/90, I'll have to look in the HMTG.