Thanks Patrick, yes I'm definitely going to try towing in D and see what happens. Oh and just to be clear, in no way was I picking on Ben about the 3 or D for towing. I'm just trying to figure it all out.
I did drive the freeway for a while and my findings seem to mirror Grit with only getting lockup in 4th. But it's not always easy to watch the tach and the traffic and the speedo etc. So I might try it again with one of my kids as passenger watching the RPM's on my ELM327 scan tool while I drive.
One method I used to try to verify or force lockup in 3 was
- I drove in 3 and put the tach as close to 3,000 rpm as I could.
- I held my foot still and drove for about 10 seconds to make sure the trans was in whatever state it wanted to be.
- Without moving my foot I shifted into D.
- I watched the tach drop as it hit 4 then drop again into lockup.
- Still not moving my foot I shifted back to 3.
- The tach jumped immediately to 3,000 and seemed to stay there for at least 10 seconds.
I'm assuming that the transmission would come out of lockup for the shift. If I'm wrong then my test method was a bust.
