Turning O/D off in city to prolong transmission life?

[Cekkent]

I was driving around yesterday in the city and turned the O/D switch off. Car stopped being sluggish when accelerating (ECU selecting different program when O/D off?).

So I was thinking: If I refrain from driving around in overdrive in the city, would this help improve transmission life due to reduced engine heat and increased engine rpm pumping larger volume of transmission fluid through the radiator?

I'm working on installing an external cooler, but was just thinking of some additional things.

[maxnix]

I thought Omaha was pretty flat?

Using 3 or OD off until over 55mph on the level and not accelerating is a good use of the ratios. VH41DE likes to rev, which is good for a heavy car.

[Q45tech]

There is a 33% difference in rpms between 4th and 3rd. In theory the difference might be as high as 20-25% higher fuel consumption depending on lots of variables but it will surely be 10-15%.

The difference between steady highway cruise and mild city accelerations is 23/17 or 35%.

In city it is ~ 10% worse than 17 or 15.3mpg maybe only 16.

Try it for 10,000 miles to give us an average decline.

My trimode ecu just raises the low load shift rpm 500>1000 rpm so you can even see 0.5 mpg with it not in oem standard position.

[Q45tech]

You have to balance the prorated cost of having an AT transmission [roughly $350 - $450 prorated and saved per year vs the $150-250 more in gasiline you might burn.All depends on when fuel goes above $3 and by how much.

[Cekkent]

I got 23.43 miles per gallon last tank about 40% highway/60% city.

A 35% decrease is 16.22 mpg. That might be a bit much, but I suppose i'm willing to try it.

I thought Omaha was pretty flat?

Using 3 or OD off until over 55mph on the level and not accelerating is a good use of the ratios. VH41DE likes to rev, which is good for a heavy car.

It would be nice of the transmission weren't so eager to keep the RPM as low as possible. Are there aftermarket/performance TCUs available for Y33?

And, Omaha is about as flat as Austin.

[maxnix]

No after market TCU. Maybe because of hoe I drive, I notice virtually no difference in mpg by excluding OD below 60 - 65 mph.

[Cekkent]

Last tank, which is the first tank that i'm proactively switching O/D off below about 60mph or so, netted 23.79 mpg.

I'll do a few more and see how it averages out.

[paranoidjack]

Thanks for the report back! Keep us in the loop. I'm curious to implement this as well, I just love how responsive the car is at speed at higher rpm.

[oldmako]

When one takes into account the angle of the dangle as compared to the juxtaposition of the magnatometer at normal angles of deflection and angst on a standard atmospheric day at sea level, the bias toward nominal deflection on the HP/TQ curve and it's resultant curvilineator reaction of the TMC postulator leaves the sublimination void on all but the most basic of torque curves.

[goody90q45]

You've been reading too many of Q45Tech's posts.

[KingKarl]

OldMako, are you by chance related to Professor Irwin Corey? Professor Corey once said, "No matter where you go, there you are."

[Ludeaem]

I don't know how you got 23mpg from just 3rd gear. I have only had 3 gears for the last year almost and the best i got was 19mpg and that was being easy on the gas. Granted i did some highway traveling were i was at 55-60 and the rpm's sat at 2500-2800. Im taking it to the shop today actually to get it looked at. Fancy people with 4 gears :P