5-90 said:
Why not tow in OD? I brought a 3000# box ATL-SJC doing most of the driving in OD without any trouble (switched to direct drive in the Rockies, but that's about it.)
That's just it, though - I'm not towing anything. The only rust on my truck is on the factory trailer hitch(the reason I made the concession and bought an automatic in the first place), and it's so bad that I don't trust it enough to tow with it. Regardless, this was occurring with myself and one passenger, and the rest of the truck full(to window level) with camping and hunting gear.
The AW4 can almost be said to have "six" ranges - 1/2/3/3L/4/4L. Torque converter lockup can happen in third or fourth at a steady-state cruise, and it should drop right back out whenever you "blip" the throttle or change speeds. The advantage to lockup is that it turns the TC from a hydraulic coupling with slip into a direct mechanical coupling. This also has beneficial effects on fuel economy, fuel efficiency, operating temperatures, and engine state (the lockup helps to eliminate "hunting" at speeds.)
It doesn't drop back out of lockup until it downshifts all the way to third. If it would drop out of "4L" as you call it, and into "4", I would be thrilled, because that's exactly what I want it to do. Instead it bypasses "4", "3L", and jumps all the way down to "3". And at lower cruising speeds, it does "hunt", as it's constantly locking and unlocking. If I drive the truck in "D" for even a short period of time at 25-30 mph, it hesitates horribly and often times backfires if I give it any more than 1/2 throttle. Not so if I drive it in "3" or keep my RPMs up by speeding(which I try to avoid as best I can).
Eliminate OD? Same way I "eliminate" OD on my BA-10 and my AX-15 - just don't use it. "Third" is "drive" - you have 1/2/3/3L available, but not 4/4L. Problem solved.
Yeah, but 75mph in 3rd gear doesn't make a whole lot of sense.
As mentioned tho - note that the TC locking/unlocking can feel like a "soft shift" - if you're in OD climbing up to freeway speed from a standing stop, you'll actually feel (if you pay attention) the shifts 1/2, 2/3, 3/4, 4/4L. (You don't hit 3L because you're still accelerating.)
I'd not suggest manually disabling the lock either, unless you are attentive to your driving and vehicle. As mentioned, the lockup will both reduce operating temperatures and increase economy and efficiency, and it should be retained.
And herein lies the problem. I feel that "soft shift" when it shouldn't be shifting at all(hell, it shouldn't even be anywhere near overdrive at 25-35mph), and it won't give me that "soft shift" when it should(1/4-1/2 throttle at highway speeds).
I am a very attentive driver(this comes from years of driving manual transmission vehicles, including some requiring me to hold a CDL), and I have never in all my years of driving experienced this type of thing with ANY other automatic vehicle I have driven.