Overdrive gear is there to give the best fuel economy
when the vehicle is on flat ground or going slightly downhill.

It is not meant to be a hill climbing gear.

I am not sure how people began to believe that an automatic
transmission was never supposed to downshift on the highway
but many certainly do, and complain bitterly
to the dealer and automaker that their vehicle is 'weak'
if it downshifts on a hill.

If your vehicle can climb steep hills in overdrive
that is an indication that the 90% of the time
you are not climbing a hill
you are getting worse MPG than you could get
with the right gear for flat and downhill sections.

MDS is an attempt by Chrysler (and GM, Honda)
to satisfy customers who never like to ever feel a downshift
but MDS give a bit worse MPG than if correct gear ratios were used.

The CVT transmissions Chrysler buys from the Nissan subsidary
JATCO and factory installs in the Dodge Nitro car
are another tack on an attempt to create a transmission
with gear changes that can hardly be felt,
but then some customers complain that they miss the feel of
shifts during acceleration and think their trans is constantly
slipping. Audi had the same customer complaints with their
CVT trans

Perhaps the DSG transmission that US Company Borg Warner
jointly designed with Volkswagon is the best blend because it has
the world's fastest shifts.

With ex-Volkswagon President Wolfgang Bernard
now the chief Cerberus manager in the Chrysler buy-out
the top management of Chrysler will certainly know about
the DSG transmission.

 

both Barnes and Noble
and Borders bookstores
should have the latest Engine Masters issue
and both allow you to sit and sample read articles
before deciding to buy:

http://www.popularhotrodding.com/enginemasters/

 

My truck handles hills in overdrive if I so decide. It did so even before I put the 4.10's in. Personally Iusually take my vehicle out of overdrive if I am on a really steep grade. I just feel it is better for the tranny. My biggest problem is not what the truck is capable of but the traffic around me often forces meto slow down and then the truck drops out of overdrive. Anytime you get into a situation where your truck is shifting back and forth like that it really is hard on the tranny. The difference in gas mileage is really not that significant and it sure beats having your tranny go out.

 

The idea that overdrive shifting wears out the 46/47 series automatics is a common one, but the experts have other ideas:

http://www.dieseltrans.com/phpBB/viewtopic.php?t=33

The gears in the overdrive unit of a 46/47/48 are actually the same as the front planetary used in the legendarily strong 727 used behind torque monsters like the 436 Hemi. You can see that from the ratios 0.69 = 1/1.45

The weak points of the 46RH series is in Chrysler's use of poor quality seals and O-rings, which maybe saved Chrysler $10 per transmission but cost customers thousands.

The weak points of the 46RE series is the variable line pressure software used by the PCM computer and the VFS solenoid that was added to the valvebody to take the place of hydraulic circuits.

 

We're getting off topic here, but that was a goodread about the transmissions at dieseltran.com. Thanks for the info HankL. If you have any other info on the Smart Controllers, let me know. I've been thinking about getting the tranny to lock up in 2nd gear. There are times when I am towing up steep grades and can't get out of 2nd. It would be nice to get it to lock the torque converter so the fluid temperatures stay cooler.
Trying to tie that back to this topic, if your motor can't pull the hills in OD, turn it off and let the tranny go into 3rd gear. The torque converter will lock up, dropping your rpm's, and you will have much more power to pull the hills. I've found that even though I'm running a higher rpm when in third lock-up, I use less throttle to pull the same hill then if I have it in OD. I'm pretty sure that if you do not manully turn off the OD, the transmission will not lock up in 3rd gear. So when you hit a hill and the tranny needs to down shift, it will go into 3rd gear, the torque converter will not lock up, you will be running higher rpm's and your tranny fluid will heat up much quicker. It's best to hit the button on the shift **** prior to the hill, give it a little gas to smooth the downshift, and get into a more workable power range with the motor. Of course it all depends on your truck, the terrain, and the traffic around you.

 

I also am thinking about adding a permanent switch to ground the torque converter clutch electrical circuit and engage in 2nd gear. I have tried this with a 'remote starter' push button and it seems to work ok.

The new 48 series auto behind the Cummins will lock the TCC in 2nd gear.

Around the model year 1997-1999 Chrysler tried a PCM software change where the 46 auto was locking up 2nd gear, but many customers complained about all the shift jerks and Chrysler had to issue a TSB to do away with 2nd gear TCC lock-up.

I wonder whether BG Chrysler could do custom flashes to lock the TCC in 2nd gear under the right circumstances?

Since the 'Overdrive Off' button is already there is would seem simple to allow 2nd gear TCC lock-up after 15 seconds if the OD button has been turned off.

 

Looks like we are thinking along the same lines. I want to ask my friend about this. He's a pretty good transmission mechanic and should have some good insight into whether this can be safely accomplished. I'm curious about the 2nd to 3rd shift if the TC is locked up. Will it be a direct shift from 2nd lock-up to 3rd lock-up? If you're overriding the system with the switch, you would have to be careful about making the shifts. If you figure something more out with this let us know.

I was looking up the Smart Controller over on the dieseltrans.com website. It looks like you need to have their valve body and it is only available for the 47/48 transmissions.

 

I have enough years as a mechanic to be capable of checking all the things suggested to check andI can't find any problem with my truck. There have been people bragging about how great their truck climbs hills to others saying they have no problem on hills to others providing helpful suggestions. I have driven enough vehicles over many years to believe that my truck is inherently lacking torque at 2000rpm. It runs really, reallygood at 3000rpm. Buc started this thread and described my situation perfectly. So, I have some comfort knowing at least one other person's truck is like mine. Maybe someone with a similar experience will read this thread and have a solution or just provide some more sympathy.[&o] Unless someone can say a specific mod definitely adds low end torque, I won't be throwing any more money at my truck on mods that may work. I need the money to pay for gas.[:@] I'm not ready to sell my brick and buy a Ford or Chevy.....not yet.Mainly because there are alot ofhelpful people in these forums. Peace.

 

Okay, I sympathize. You have the Superchips, which should help out if your PCM had the "Death Flash", which basically retards the timing. How about tire size? Are your tires stock? If they are oversize, that will cut down on your torque. Simple tune-up of plugs and wires might help. I run NGK plugs and have no problems with them. Another thing might be the defination of a hill. I drive in central PA. Our grades aren't long, maybe 2 miles at the most, but they can get steep. But they aren't nearly as steep as driving in the foothills and mountains of Colorado.

Maybe you can try some fuel injector cleaner, Sea Foam, or Mopar Combusion Cleaner. Other than gears or a cam, I have really never heard of anything that will significantly improve low end torque.

I used to own a 92 Ford with a 351 EFI and 3.55 rears, basically the same as my Dodge. The Ford was a dog, and it was an extended cab short bed, so it was evena little lighter. Even before I started modifying my Dodge, it had more power and gruntthan the Ford. The mods I described in the earlier post definately helped the low end. Not a great amount, most of the improvement was in the top end. Try advancing your time with the CKP mod. Just listen for pinging and move the sensor back if that occurs.

 

try some engine restorer... can get it pretty much anywhere. just toss it in when you do an oil change. it seemes to have really helped my friends and their vehicles that are all 100k plus. so with these engines we should probably start doing it at.. oh 50k.