[quote author=ess2 link=board=23;threadid=2059;start=msg14469#msg1446 9 date=1088362721]
Thanks for the advise on speed. I am really surprised to hear about the Tundra TX- I though it was bullet proof like the rest of Toyota! I had planned to go 60-65 mph but keeping up with traffic has always worked for me. DW will be happier below 70!! The truck has only 7K miles on it so maybe I didn't harm it. The tire limits are something I'll respect for sure!! Thanks again I'm never to old to learn (78).
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Most welcome. Heres a bit of amplification.
WRT to the Tundra tranny, I forgot to note last night that to-date all of the sad towing related transmission posts at TundraSolutions have come with those who own '02 and earlier (particularly '00) models...and that generally the problem didn't show up until the truck had around 50K miles. Beginning with the '03 models, Toyota made undefined "changes" to the Tundra transmission...one effect of these changes is that unlike the earlier models which could use standard Dexron ATF, the '03s and '04s must use Toyota's Type T-IV ATF which is a "HFM" (Highly Friction Modified) ATF. There has been some speculation that Toyota somewhat strengthed the front planetary gearset, and changed the programming/lockup pressures/friction material of the internal clutches. However, the transmission's model number did
not change in '03...it was and remains an "A340E" (the E means the transmission is electronically controlled by the engine's ECU...the nearly identical transmission used in the V6 Tacomas is an "A340F" with a mechanical linkage for kickdown). So, given the lack of reported problems in the '03s/'04s it is
possible that Toyota fixed the transmission's towing related shortcomings and it
may be safe to tow with OD on. It's worth noting that TundraSolutions has around 26,000 registered members so if there's a recurring problem we will likely hear of it. The guidance I give to folks asking towing related OD questions at TS.COM is as follows (as of today I'm now also the "towing" moderator/guru as well as one of the two engine/drivetrain moderators/gurus over there):
"If the trailer weight is below 2000 to 2500 lbs and most towing is on level ground at elevations below 3000 feet and the truck is an '03 or newer, try towing with OD on. If there is little to no "hunting" between OD and 3rd and the torque converter clutch seldomly unlocks on slight grades, it is most likely safe to use OD. However, if the trailer is over 2500 lbs, the towing is in hilly to mountainous terrain, or the transmission frequently hunts or has TC unlock, or the elevation is high (lower engine power), then simply turn off OD when towing and be done with it. "
Although you are at low altitude, your 3023 will most likely weigh between 4500 and 5000 lbs after you and your DW finish loading it (As a point of reference, I travel solo and fairly lightly and my 2720SL comes in at 3800 lbs with empty tanks!). IMHO, 4500 to 5000 lbs is a high enough weight that OD towing is just not prudent if you are interested in long life from your transmission. FYI, a tranny rebuild on this truck will run around $3500 in today's dollars.
WRT to the best towing speed, I use an approach suggested by a couple of law enforcement acquaintenances. The concept is to choose a speed that considers both tire life/safety
and traffic density/safety. If the traffic is light to moderate and other drivers can change lanes to pass me without having to change their speeds or, in turn, causing the other traffic on the road to wait/slow down, then 65 is a good speed. However, when traffic density is moderate to high and 65 is more than 5 mph under the prevailing speed, I will push it up to 70 (or a bit more) so that I minimize the traffic turbulence I will be causing; namely drivers having to slow/brake to let other folks get around me. As my law enforcement pals have pointed out, a too slow driver is almost as much of a traffic hazard as a too fast driver. Thankfully here in Colorado, moderate to high density traffic situations only exist for about 60 miles each side of Denver on I25...the rest of the state (and rest of the western states) has light to very light Intersate highway traffic on the weekdays I normally travel on.