48re - Max Towing / Short Distance

[DBVZ]

As I understand the 48re, it has a lockup in manual 2nd gear that stays locked since it does not shift. So here is the question:



If I want to pull somthing big a short distance, like to get it off the road, what is the best I can expect? I thought I could put it in 2nd, and in 4 X 4 low range, to get lockup and a low gear ratio at all 6 tires. That should be max towing with the 48re, for a short distance at low speed, right?



My next question is what I can connect to at the back of the truck that will not be hurt by pulling that hard? Direct to the rear axel? Perhaps a triangle from each side of the axel near the wheels, to the drag? Each side rear spring shackle on the frame rails?



I have a 20k tow rope that I suspect would part before I broke anything on the truck, but I don't want to bend anything important just giving a little roadside assistance. The Cummins HO has the power, but I just don't know much I can use by being attached to the Dodge part.

 

[LightmanE300]

I'm assuming if you were going to pull someone out of the snow or mud, you'd hook the strap to your trailer hitch, no?

 

[MCummings]

Using the factory hitch, sled pullers hook to, and drag a sled that weigh 40,000+Lbs, as fast as they can.



I don't think it is a good thing to hook to suspension compnents.



Merrick Cummings Jr



EDIT:



https://www.turbodieselregister.com...&threadid=75536&highlight=Challenged+pull+off



This is a good thread,, Great Advice in there!

 

[dmurdock]

Definately use the hitch... you might end up ripping expensive pieces off otherwise.

 

[Kilby]

The 48RE does lock up in 2nd but I don't know if it'll lock up in 2nd while in low range. The truck might need to see a certain speed before the puter locks up the converter.



Definitly do not attatch to the axle! Attatch to the trailer hitch. If you don't have one, get one.

 

[Dean Upson]

Originally posted by Kilby



Definitly do not attatch to the axle! Attatch to the trailer hitch. If you don't have one, get one.

I use a big clevis pin and shakle on a hitch bar and it works very well.



Dean

 

[DBVZ]

Ok. I was concerned that the factory hitch cross member and bumper would bend pulling that hard, but if they can pull a 40,000 pound sled with it that should not be a problem. As I said, the rope would part first.



Actually, I was more concerned with the stuff on the axle than the axle itself - like brake lines. It seems to me taking the power at or near the wheels would put less strain on the connection and suspension components (axle, springs, spring shackles, hitch) than taking it at the middle of the hitch cross member; but if I don't need to I certainly won't. The force is generated by the rotation of the tires at the pavement, after all; and everything on up needs to be strong enough to handle the transfer of that force.



Next question: Anyone see a problem pulling hard on just one of the front hooks? I wonder about keeping the frame square.

 

[DBVZ]

Originally posted by Kilby

The 48RE does lock up in 2nd but I don't know if it'll lock up in 2nd while in low range. The truck might need to see a certain speed before the puter locks up the converter.

Does anyone know for sure about this? I was assuming it would lock based on engine RPM, not vehicle speed. In which case it should lock up at about 5 mph in low range, which is what I was looking for.

 

[robertyoke]

Originally posted by DBVZ

Does anyone know for sure about this? I was assuming it would lock based on engine RPM, not vehicle speed. In which case it should lock up at about 5 mph in low range, which is what I was looking for.

the only time lock up occurs in second is when trans temp goes above 220 deg. in the pan. temp was 270 deg. in out put line. I tried low range to see if lock up occurred , I don't think it does .

 

[Kilby]

Originally posted by DBVZ

Does anyone know for sure about this? I was assuming it would lock based on engine RPM, not vehicle speed. In which case it should lock up at about 5 mph in low range, which is what I was looking for.

If that's the case then it'd lock up while in park and someone stepping on the gas.



robertyoke, I'd have to check again but I'm fairly certain that mine has locked up before the trans or engine even warms up. Maybe I'll try it again tomorrow if I remember.

 

[DBVZ]

I just checked the manual, and I think I agree the 2nd gear TCC lockup is only reported as for high trans fluid temp. Unfortunate. Well, at least if it gets hot enough it will lock. (page 2153, 21-314)



Also, the manual says all shifts are determined by three things: The manual lever position, the throttle pressure, and the governor pressure. Speed would be the result of the governor pressure and the selected gear, right? But speed itself is not a factor, directly. So in low range lockup should still occur in 3rd and 4th based on these three factors, but at a reduced speed due to the reduction ratio. I think low range is 2. 72:1.

 

[DBVZ]

Low Range / Drive / OD off

I just ran the gear ratio numbers again, and with 2nd at 1. 45:1, and 3rd at 1. 00:1, it looks like if I want lockup in this situation I should just use Drive, with the O/D off. Lockup in third should be at about 10mph in low range. It means going through 2 shifts though, with the slippage of the clutches at each shift under load.

 

[Kilby]

You sure are putting a lot of effort and thought into this. What are you planning on towing that requires this much effort? Do you plan on doing it often?

 

[BHolm]

Why would you want the convertor to be locked? The torque convertor MULTIPLIES the torque to the rear wheels. The absolute most power you can put down is in first gear low range, it ought to pull your house

 

[DBVZ]

I am a planner. I like to think things through before I try something. I don't plan to do it often, but when the situation comes up I just wanted to be confident about what to do.



As for why lockup, it is just to save the transmission since lockup should reduce trans temp when pulling hard. 3rd or 3rd lockup should be the same ratio, except lockup would be without slippage.

 

[robertyoke]

DBVZ



you may be right I did not spend a lot of time driving in low range and don't plan to tow in it so did not care if tcc locked or not . You are right about the three factors which make the trans shift but we are not talking about shifting, but if the tcc locks up or not . The valve body on the 48re supports lock up in 2nd,3rd,&4th gears but its the pcm that controls lock up . Temp is one factor that the pcm uses but I think the other is speed , both 3rd & 4th gears lock up tcc at around 48mph whether you got 3. 73 or the 4. 10 gears. also putting the transfer case in low range sends signal to the pcm and maybe cancels out lock up ??? don't know and this is my first auto truck so still learning .

I can't go test for stock lock up any more 'cause she is no longer stock

 

[Kilby]

I tried a few things tonight on the way home. When leaving work, (drivetrain cold) and the shifter in "2", the lock up does work. Will it work when the shifter is in drive, the foot is down, transmission in "2" and trying to pull a load? I dunno.



Low Range. The transmission did not lock up the converter in 1, 2 or 3 gears. Didn't try OD. Now, I didn't try it a lot, just gave it a quicky try. YMMV and all that.