OD OFF vs. Tow/haul mode

[BSilveira]

What is the difference? I noticed the new 3rd gen have tow/haul mode. My '03 has Overdrive off. Is this the same?



thanks,

Brian

 

[DPKetchum]

No. Od off is actually keeping it from shifting to od(4th gear) Tow/haul changes the shift points and that includes od or 4th.

 

[bagd99dak]

i got the tow/haul on mine, still goes into overdrive. the only think i noticed is that is seems to lockup the torque converter in third gear as well as o/d. i havent noticed a shift point difference at all. but when i tow it is usually under 7k. i kinda like the way it works. although i could imagine if you tow 12k threw some serious mountains it would probably be nice to shut off overdrive.

 

[DPKetchum]

Pull it into 2nd above 50 or more mph and it will stay in third but no od. It won't drop to 2nd until slower speeds but won't go into 4th(o/d)

 

[RIDGERACING]

Isint that the same thing as turning OD off

 

[SThorud]

It won't go into 4th as easily as normal driving is what he's saying.



The Tow/Haul mode is just a change in the shifting characteristics of the transmission, but if you're cruising in town and never going above 45mph, I personally want to keep O/D off but on the '05 trucks they only had tow/haul and would shift into O/D right around 40-45mph with light load.



There were enough complaints about this that now in '06 they have O/D off and Tow-Haul mode.



In prior years it was always O/D off. People weren't smart enough to know that they should use that when towing so they changed the name to Tow/Haul Mode and it was still the same function. Then, like I said, in '05 they changed it to different shifting characteristics but there was no way to turn O/D off.

 

[RIDGERACING]

On the 05s can you put it into 2nd at a stop so it will not go into OD or do you have to be moving above 50mph?

 

[BHolm]

On the 05s can you put it into 2nd at a stop so it will not go into OD or do you have to be moving above 50mph?

No, if you do that it wont shift beyond second. If you shift it down to second at speed the only reason it doesn't go into second is because it would over rev the engine, so it selects third until the speed is low enough to go into second.

 

[JCaserta]

so say im towing 12k with an 06 48re, should i just put it in tow/haul or put od off until i reach say 60mph or so and then let it go into od?

 

[Moose Truck]

47RE vs 48RE

What is the difference? I noticed the new 3rd gen have tow/haul mode. My '03 has Overdrive off. Is this the same?



thanks,

Brian

Brain, the 2003 used the 47 RE carried over from the 98. 5 - 2002 24 Valve 2nd Gen. For the 2004 and up 3rd Gen, they got the 48RE, a beefer transmission, with a different "Brain Box". I think instead of the PCM, it uses Cummins' ECU. Moose00

 

[DPKetchum]

The EARLY 2003 S. O were 47re. The CHANGE was in the first qtr of 03 to the 48re. All H. Os and the S. O. s went to 48re. I'd use TOW HAUL unless the situation(big inclines) or what not caused lots of up and down shifting from 3rd to od etc. Its what tow/haul is for.

 

[MStaggs]

The EARLY 2003 S. O were 47re. The CHANGE was in the first qtr of 03 to the 48re. All H. Os and the S. O. s went to 48re. I'd use TOW HAUL unless the situation(big inclines) or what not caused lots of up and down shifting from 3rd to od etc. Its what tow/haul is for.

Do the 235hp Calif spec 04's also have the 48RE?

 

[DPKetchum]

The 48re was used across the board at its conception. D. C. did not use BOTH 47re and 48re on 3gs once the 48re was introduced or if any overlap it was minor etc.

 

[MStaggs]

The 48re was used across the board at its conception. D. C. did not use BOTH 47re and 48re on 3gs once the 48re was introduced or if any overlap it was minor etc.

Thanks!

Are they as "weak" as I have read?

 

[DPKetchum]

Weak? which? The 47re is ok but it had a somewhat high failure rate. I've seen many with tons of miles and no issue. Hardly ever read about a 48re failing unless truck modded over 100 h. p. extra.

 

[MStaggs]

100 HP over what?

There are three power ratings for these motors.

For example, how far can I push my 235HP 48re?

 

[broeser340]

A stock '05 is rated at 325 hp and 600/610 lbs. of torque. An '05 has the 48RE. I searched for this thread because of a statement in the new mag. Issue 51, page 108, Transmissions, third and fourth paragraphs. It sounds like they are updating '05's to include both overdrive off and tow/haul with a new switch and PCM reflash. At least they are maybe trying to so that we can maybe get an exhaust brake on the autos. I'm all for that. Anyone have the dealer reflash their PCM to the '06 software and install a new switch on the end of their gear selector? I would like to know their experience with the retro and how much it costs for them to do it. Did they add an O/D off indicator on the dash for the '06's? Or has it always been there but turned on or off from the PCM. Maybe I should have gotten a six speed.

 

[DPKetchum]

MSTAGGS. Thanks a good guestion. Well MOST all posts and BomBS discussed are on the OTHER 48 state trucks and are H. O. s So I would ASSUME 380/400 h. p. since their 305 to 325 h. p. stock.

 

[MikeBeggy]

FTI,I have an 05 with the computer controlled shifting and I installed a lock-up device which also has dash lights to indicate what gear the trans is in. When I use the tow/haul button, the trans sfts from 2nd to lock-up and then to 3rd. I also have a triple disc convertor so under heavy throttle upshifts, the convertor is already locked going into 3rd and the last shift can be harsh. Nomally, the convertor acts like a cushion when the tow/haul feature is used. I wouldn't have known what the trans was doing if I didn't have the lights showing what gear and lock-up was happening. I hope I descrbed that clearly. Just more info.

 

[Turbo_Bob]

100 HP over what?

For example, how far can I push my 235HP 48re?

325 H/P would be safe.