Hi Guys,

Hopefully this is not "beating a dead horse" but.....

From my sig you see I have 265's, 3.73 rear, 4wd and no perf mods other than smarty Jr. I was running on the smarty Jr 70 hp tow setting for a while but I lost my nerve and went back to economy level 1 after hearing about people having their transmissions slip....at 75 mph after lockup. I like the 70 hp setting better though and I think it may have given better economy also (running empty) So here goes the question:

Is it safe to go WOT on a stock tranny with stock size tires (empty truck) if you wait until you are going down the road pretty good, say at least 40 mph. Really I would like to be able to do it down at 30 if the TC would stay locked up, but thats a different story. I want to be able to step on it hard to pass slower cars than me who are going like < 45 mph but dont want to damage my transmission. I know you should not be WOT from a stop even with stock power. I dont beat on my truck much....

Please let me know your honest opinion about that. Seems like the torque would be way over the 700 ft lbs TC rated limit at peak torque but that you probably would not be in that RPM range anyway.

Also, would being in tow/haul mode help because of the increased line pressure in the transmission??????

 

Would like to know the answer to this as well

 

I slipped my clutch on level 2 while towing 20,000 lbs of drill pipe.
Dumb thing to do.... I knew better.
85,000 miles on my 06 with lots of real heavy towing plus adding a Smarty.
I expected it to slip.
I'll be buying a clutch soon.

No matter what I tow or don't tow, from a stop I've never had to floor the throttle to go anywhere, or get out of anyones way.
I don't race my 11,000 lb daily driver/work truck.
I know that I can break things faster than I can fix them.

Going down the road at 50mph or so, you can get away with mashing the throttle.
But at 30mph, IMHO thats not a good idea.
It doesn't take much throttle to pass a slower vehicle.
If you need to mash on it to get around someone,
chances are that you shouldn't be passing in the first place.
There's almost always a passing lane or a safer place to pass up ahead a bit.

I'm not sure if a Smarty does anything to the TC or shift points or pressures.
It would be nice if one could adjust when the TC locks with a push of a button. Is there such a thing?
I doubt that you can find an auto that wont down shift into 2nd or 1st.
These trucks make gobbs of torque in the stock form.
Add 200 ftlbs.....add the chances of breaking things.

With your auto, chances are that you'll be fine.
Auto's are more forgiving than manuals.
Use the tow/haul mode...
Its there for a reason.
Keep an eye on your trans temp.
Remember, Heat kills.
Down the road you can just about plan on spending some $ on a your trans.

When I bought My Jr, It said that it was safe to use on stock trucks.
But I and I'm sure most of us know that adding more HP to a stock truck is never a safe thing to do.
I certainly don't and wont blame JR. for making my clutch slip.
I'm the fool who mashed the throttle.

 

I might have this all wrong but I would think it's alot easier on things to mash the throttle without the TC locked. It's the clutch surface in the TC that's going to take a beating mashing the throttle locked. An unlocked TC will build heat faster but if your only mashing the throttle for a few seconds or 1/4 mile run I don't think it could build heat that high that fast. My feelings on mashing the throttle going at speeds is not good. Build high Hp, slam it into a lower gear can not be good on a transmission. I would rather spin the tires at the same time gaining speed would easier on the transmission.

If I'am going to hot rod around I do not use T/H for those reasons.

 

pwr2tow is correct. It is less harmful to your auto tranny to mash the throttle from a stop than from a roll with the TC locked. The TC is the weakest part of the 48re. Full throttle highway passing will cause you more potential problems/damage than stop light to stop light drag racing.

With that said, some of the trannies seem to hold up a little better than others. If it were me, I would not hesitate to run the 70hp setting on the stock tranny with an unloaded truck. I would not do it towing. But, even with an unloaded truck it is possible your tranny might not like the 70hp setting eventually. It will hold up for a long time for sure, but eventually it may cause you problems. Again, if it was me, I would run it. Especially if you don't beat on it all the time.

 

I've had the JR since December and haven't taken it off of the performance tune (100hp). I have driven roughly 5-6thousand miles with this tune and have not seen any problems YET!! I am also not afraid to stomp on it from a dead stop nor am I afraid to stomp on it from any mile an hour. I do think that I will need a trans eventually, but I also think that some people don't give the 48re enough credit, not saying its the best out there, just saying. I keep up on maintenance and I don't tow with my truck nor I am I hard on it everyday. I let others determine whether or not the power comes out, if you know what I mean. Drive it and enjoy it, thats why you bought it. Also remeber it does have a "safe" limit and will defuel between shifts, it was made for a stock truck, just drive reasonably.

 

Thanks for the responses guys.

Do you know which of the 3 settings econ, tow, perf modify the torque management??

I am guessing that modifying the torque management much is where the biggest risk to the tranny would be. I worry too much to put the thing on the 100hp setting, just to play it safe. But i sure would like some reassurance on the 70 hp setting cause I like it!!! Others have had trannies slip, think mainly TC, but maybe they already had problems, needed bands adjusted, were towing really heavy, etc ....

 

Ive been on 70 hp for a month. no transmission slip. All stock trans. I like the 70 hp setting the best. It runs very well with my truck. When I tow I will go to 40 hp. Sorry, I dont know about the torque management.

I had my trans rebuilt in dec 2007. It went out when I was all stock. Anything mechanical has the risk of breaking down. I didnt let it stop me buying the JR. I think it makes my trans shift better!

I took my truck into the dealer last week to get the stearing box replaced and I took it back to stock. Stock sucks!!!!