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I'm noticing our 2005's transmission doesn't behave terribly well for gas mileage. For one thing, the torque converter doesn't lock up as often as I'd like. Around town, pretty much never. On the highway, only on level ground, downhill or the most slight inclines. It doesn't take much of an incline on the highway to see it unlock and watch the gas mileage plummet :(

I know the 3.5 VTEC has the torque to pull those hills locked, and I don't see why it can't be locked up at lower speeds like many other late models.

I'm reading general information around different sites about wiring up a switch to activate the TCC. Anybody tried that? What are the potential pitfalls, or IOW, would this be bad for our MDX?

I also wonder if with this transmission it would be possible to manually select a gear. Anybody done that?
 

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Main issue is Torque Converter size which will cook if you tried to lug the engine to pull those hills, Then you have GRADE LOGIC which wont even allow to climb with it locked.

The J35 has the torque but way up the power band, at highway speeds the engine is REVing in the 2000RPM area which is not where the engine builds up its maximum torque.
 

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Jenn348, this has been my one real complaint about the 1G MDX. I agree with skirmich that you really wouldn't want to force TOO much lugging on the system, but I'm sure there is a lot of room for improvement of the road manners without risking a TCC meltdown. It seems that my MDX downshifts ever time I cross a paint stripe. ;-)

If the MDX had a mode switch (sport / economy) or a manual shift gate option, it would be nearly perfect.
 

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I actually love the fact the MDX downshifts so easily.. All the Torque sits up above 4000RPM so downshifting is the fastest way to speed up in the heavy MDX.

My TL-S AUTO lugs so badly that it will only downshift when doing half throttle and will only kick down 3 gears under full WOT.
 

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Sounds like if I could swap my tranny for skirmich's TL-S tranny, we'd both be perfectly happy! ;-)

I do understand about the advantage of using the high RPMs to keep the power up, which is a good thing if you're really trying to wring every bit of performance out of a 4,400 pound SUV. But for road tripping, you really just wanna get there for the lowest investment in gasoline, and the constant downshifting really drops the mileage potential. Some day when I get enough free time, I'm going to figure out a way to fool the TCM into acting like I want it to. ;-)
 

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I never have an issue locking up my TC in a straight line with just the Cruise Control:

(Speed says 40 because I let go the throttle in order to take that picture, That was real hwy mpgs at 60mph flat road)..

If I want to overtake or climb up a hill I do want all of my Engine Power Potential, I live in San Diego and Baja California, México so there is tons of unleveled roads. The only way I could get that MPGs was because of a long famous stretch between Tecate and Mexicali, México known as "La Salada" and Hypermiling it HARD..

I know this is a 1st gen MDX inquiry but it also applies even more since the 1st gen has a weaker engine and around the same weight as the 2nd gen and the same 5 forward speeds.. The 1st Gen has to push a lot of weight with less power thus the Transmission has to cycle even more than the 2nd Gen.
 

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I consistently get 20-21mpg on my cross-country trips. Of course, I'm driving 80mph or more for about half of that, so it's not all that horrible (no way you're going to push a box the size of a 1g MDX that fast without losing some MPG). There are a lot of very shallow, long hills on the route, and I know the mighty 3.5 is capable of puling them easily in 5th without stressing everything. Instead, the TC unlocks and I watch the MPG indicator drop a few increments (including the times when it climbs the first half of the hill easily in 5th and the second half isn't any steeper, but is just right on the edge of the parameters that unlock the TC).

But the worst is when I'm driving 80mph going west on I-10, and a headwind forces me into 4th gear and I get about 12mpg. ;-)
 

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That is good MPGs for 80mph to be honest.. I would get around the same amount of MPGs in my 2G at that Speed.
Luckily or Sadly California speed limits in general are 65mph so I get 25mpgs at that speed.
 
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