BenK wrote:
Curious why folks are harping on this small block's RPM while towing. The 4L80E is an 'automatic' and just leave it to it's computer to manage it. The manual does say to tow in 3rd, not OD. IF the OP is towing in OD, then the tranny will hunt and over work the gear sets
PatJ wrote:
1. Your driving style kept RPM lower than designed and therefore your converter was unlocked and you were out of torque curve. Up hills with that load and 4.10 at low highway speeds you should be locked up in at the top of 3rd. ... The tow/haul mode does more than just trans shift points so be sure to use it.
Grit dog wrote:
If I floored it at highway speeds and got kickdown to 2nd gear then an automatic upshift to 3rd with the trans manually shifted down to "3", I never felt or saw a lockup reduction in rpms in 3rd gear, but upon shifting to 4th, it would lockup a couple seconds after the shift, dropping another 2-300rpms.
This makes me question if that era of trans 4L60 or 80 does lock the converter in 3rd gear at all.
Hey Ben, there might be something to be said on this based on the last few posts from you, Grit and Patrick. For starters my 2001 manual says to tow in D not 3. My shift selector is PRND321 For grins here's a much edited screenshot.
Now here's where the possibly ah ha moment comes in. I remember when I started this tow I had the shifter in 3rd gear, and not D which is how I always pulled with my '96. So I pulled the first hill and up through the mountains in 3. If 3 truly does not go into lockup as Grit might have found then that could have been part of my heat issue. When I had the better (but not great) results when driving home I had the shifter in D and tried to keep it there to gain the heat reduction of lockup.
So while I still wonder if I have a cheap aftermarket radiator, I hopefully have some further ideas about the gears. I will probably be taking the trailer back to storage which necessitates driving the first hill. So I'll try it in D and see what happens.
And since it's 9:30 PM on a Friday night I think I'm going to take the Burb out to the freeway unloaded and with no trailer, and see if I can spot lockup on the tach.
