it does make the transmission shift better and as stated reduces wear on the clutch packs. i do not know of anyway to automatically turn it off when you start the truck, it will ALWAYS default to ON and i just tick the button as i shift into Drive first thing on every drive

however, the 46 is not (to my knowledge) a mercedes transmission

the 4.7 is connected to a 45 (or 545 in the later years) rfe transmission, this is a mercedes designed transmission, the 46 is older than the daimler/benz partnership.

 

This is kind of off subject but my dad has an 01 Ram that he bought with 50,000 miles and now has 190,000 miles and every time he starts his truck he takes it out of O/D and the truck still shifts perfect. So i wonder if he DIDN'T turn it off for those 140,000 miles if it would still shift as good?

 

Could you then put in a shift kit and leave it in O/D without doing the damage? I'm not to worried since most of my driving is at 45+ but it would be nice to know....

 

Well the shift kits I like are made by Transgo. http://www.transgo.com/


Now with a shift kit installed there is less ware as you can see even when using the transmission in or out of OD.

BUT, you shouldn't just go installing them in an old transmission because if the bands are worn it might not hold up to a shift kit. In a truck that has all of it's services and in a short life I would install one after getting an ok by a transmission builder. Also if the transmission is rebuilt I would DEFIANTLY install one!

In fact when building a transmission I do a custom valve body, over sized torque converter, and good bands.......ect

 

Have you ever modified factory torque converter Hydra? Just wondering since my torque converter was rebuilt 80,000 mi ago and the shop apparently redid some of the passages for better flow or something like that. (It was rebuilt because of the tps making the engine surge, only pointing this out as helpful tip to start with the simple stuff and safe a lot of money)

 

I tried this out to see what would happen after I read this, and I really couldn't tell any difference in the shifting, it felt the same. I also noticed that the engine RPMs were a lot higher before it would shift. I know on my friend's Suburban, when you push the tow/haul button you can feel the difference in the way it shifts. I haven't tried on the 99 Durango with the 5.2, mine has the 4.7 with the 45RFE (if that makes any difference with this, I know its built differently).

 

No I have never modified a OEM, or ever rebuilt a Torque Converter. There is no point to it other than saving a few bucks. I always have new installed and I always go over sized for more torque gains. I am not a automatic transmission guru, I am more of a manual guru. I have a transmission builder do my work on automatic transmissions. To much of a pain in the ***, but I pay good money to him. If it's normal issues I take care of them, but rebuilding one I leave to him.

The shop opened up the valve body slightly for more flow and most likely turned the pressure up a little.

The shifts are only slightly improved with the OD off because the same springs are still installed, it really isn't going to change anything as far as factory shift. But instead it helps hold the gears to help un-necessary shifting that equals less heat and less ware. Also locking out OD when towing and stop and go traffic really heats it up especially in OD.

The reason the the engine RPM's were higher is because of torque management. The lower the RPM's the more fuel mileage and un-necessary over rev'ing and the full lockup of the torque converter.

A Chevy is different then a Dodge.

Removing the torque management especially on long grade hills and such actually lowers the RPM's and creates less ware form shifting in and out of OD.


Again, I can talk all day on this subject but I'm not going to. The explanation is here and in past threads. Do as you will, this was only an explanation.

 

Thanks for your wisdom hydra

 

I've always used 3rd (or O/D off) when it was shifting in and out of overdrive a lot, such as when I'm driving on the highway in the mountains, and it starts shifting constantly in and out (my Neon did this even on small hills, it drove me nuts), and I also use it in the mountains when driving slow, and its better going down hills too. At least with my driving, I don't notice it shifting too much, but this truck seems to shift smoother than the Neon so I might not be noticing.