48RE... how does it work?

[Yo Hoot]

What is the technical side of the working of the 48RE on a 3rd gen?



I'm curious as to how it gets shift input and what makes it tick during normal acceleration.

 

[EBung]

What is the technical side of the working of the 48RE on a 3rd gen?



I'm curious as to how it gets shift input and what makes it tick during normal acceleration.

I have a 47re so that doesnt make me an advisor on the 48 but if yours has a kickdown cable like mine connected to your APPS bellcrank that could be your problem with early shifting as it was on mine. Their is a little plastic clip that holds the casing of that cable to the baracket on the APPS take the clip off and slide the casing as far back as you can (no slack) hold it there and replace the clip and give that whirl. Fixed mine.

 

[thashane]

so does the 48re have a manual kick down cable, or is it electric? Mine seems to kickdown at half throttle all the time, and drives me bonkers. I was just assuming the 48re was fly by wire, and it kicks down aggressively to reduce emissions

 

[cerberusiam]

so does the 48re have a manual kick down cable, or is it electric? Mine seems to kickdown at half throttle all the time, and drives me bonkers. I was just assuming the 48re was fly by wire, and it kicks down aggressively to reduce emissions

The 05 and up trucks don't have a TV cable, they a have a TV motor that is set by the ECU depending on throttle position, road speed, engine speed, and trans output shaft speed.

 

[Yo Hoot]

Anybody have any idea what condition would cause premature upshifting? The TV cable gives the trans throttle position for downshifts so it most likely would cause downshift issues not upshift issues ya think?

Ebung I'll check that APPS but do you think it would cause intermittent problems?

 

[EBung]

Anybody have any idea what condition would cause premature upshifting? The TV cable gives the trans throttle position for downshifts so it most likely would cause downshift issues not upshift issues ya think?



Ebung I'll check that APPS but do you think it would cause intermittent problems?

Intermitent problems probably not but it does also cause early shifting as well as lack of kickdown. With your throttle at rest your cable should tight with no slack if you want good performance. Worth checking IMO

 

[Yo Hoot]

OK after talking to Dave Goerend yesterday, he had me adjust the slack out of the TV cable. He said if it (the lever down at the trans) doesn't start moving as soon as the throttle does, you will most likely not have good pressure. This is what can cause the shift flare from 2nd to 3rd.

Two ways to adjust. At the plastic adjuster on the side of the intake at the throttle bellcrank or simply by bending the cable anchor bracket down at the trans. I chose the latter.

It made a huge improvement. I can really feel a difference in the first shifts. They are much more positive.

Gotta love Goerend for that kind of one-on-one support.

Still waiting to see if I get the premature upshifting after disconnecting the TST.