3rd Gen Engine and Drivetrain -> 2003-2007 5.9 liter Engine and drivetrain discussion only. PLEASE, NO HIGH PERFORMANCE DISCUSSION!

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Old 12-15-2004, 07:58 PM
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Unhappy 48re

I'm hearing complaints about the new 48re ,that you cant lock out 4th gear or overdrive. And lock them into 3rd gear like you can the 47re. Is this correct?? And also just what does the tow haul mode do??
Old 12-15-2004, 09:13 PM
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Locking out 4th is what the tow/haul does.
Old 12-16-2004, 12:28 AM
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i think it is the other way around...
Old 12-16-2004, 09:00 AM
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The book for the 2005 says the tow haul mode changes the shift patterns, does NOT say anything about locking OUT overdrive.
Old 12-16-2004, 09:33 AM
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Well that is what it does, pretty much the same thing as a OD button.
Old 12-16-2004, 11:57 AM
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Originally posted by bluepp
The book for the 2005 says the tow haul mode changes the shift patterns, does NOT say anything about locking OUT overdrive.
Up to 04, the Tow/Haul just locked out OD. I am assuming what DC did for 05 is what GM has been doing for about 5 years now. What the new feature does is keep you in the lower gear longer to get you moving better and not on the gas pedal as much. Only when you got up to 60-70 mph did the GM Tow/Haul let you shift into OD. If you started to lug, it immediately downshifted. The shifts firmed up a lot too. I had it on my 2000 Z71 and it was great when I hauled a heavy load.
Old 12-16-2004, 03:31 PM
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tow -haul mode works great in the 05 48re. The owners manual does a poor job- of explaining how it works. I'll attempt to do so.the shifts from 2 t0 3 and 3 to 4 or held longer and it only shifts to over drive when the load is off the tranny,in other words normal cruising. now if your cruising normal and push the tow haul button, it will take you out of overdrive into 4th,but it don't lock out overdrive,if you apply the brakes firm enough and long enough for the computer to believe you are slowing down,not just a tap on the brakes it will downshift to 3rd for additional braking effect.I'm told it works the same as the allison. I've found that I can use the fuel pedal to make it shift almost like a stick,when in tow haul mode.I pull hard to 2300rpm,lift off the pedal.it upshifts,pull hard again to 2300 lift off the pedal it shifts again and will pull hard to about 65 /70 and shift into overdrive.The shift from 1st to 2nd is not effected by the tow haul mode.
Old 12-17-2004, 10:35 AM
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That is too cool
Old 12-17-2004, 03:27 PM
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I bought a new 05 Ram about a month ago. Love the truck except for the 48re. I had an 04 Powerstroke with the torque shift transmission before this truck. I like the Ram/Cummins better than my previous truck except for the transmission. The 48re is fine when not towing; however, it doesn't even come close to performing like the torque shift or allison when towing. It seems to me DC tried to add some features to the 48re similar to the other transmissions but because of bad engineering or budget limitations they were not very successful. Here are a few facts about the transmission.

1. Turning on the tow haul feature does not lock the transmission out of overdrive; rather it simply delays the shift points to higher RPM's.
2. When tow/haul is turned on the transmission will downshift to help the vehicle slow down, however, it doesn't do a very good job of it compared to the torque shift. I'm not sure why but I suspect the torque shift's torque converter is locked when downshifting but the 48re is not. I'm not sure if that is the reason but I do know the 48re does not slow the truck down like the torque shift does.
3. The 48re seems to get confused as to what gear it wants to be in, ie, it may downshift and then upshift quickly and vice/versa.
4. When under load with the tow/haul on, the 48re may not shift to overdrive until about 60 mph. That is fine, but if you slow down (say to 50 mph) the transmissin stays in overdrive bringing the RPM's way down to the point the engine starts to lug. If you accelerate the transmission will then downshift but if you are in traffic where you can't go much faster, and you must let off the accelerator, the truck will shift back into overdrive and the engine will start to lug again.

I agree with the points made by hammajamma, after you drive the 48re for awhile you will learn ways of adjusting your driving to get the transmission to perform better. But, in my opinion, adjusting your driving to get the transmission to work better should not be required. Don't get me wrong, I would not trade my Ram for a different brand. There are many things I like about my current truck, but the 48re is not one of the things I am proud of. However, if I had it all to do over again I might still get the 48re instead of the manual transmission. I really don't want to start jamming gears every time I drive the truck. And like I said, the 48re does great when not towing a heavy load.
Old 12-17-2004, 07:32 PM
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Based on the 2004 manual and my truck shifting the Tow/Haul button on the 2004.5 will "Lock Out" Overdrive. I assume that not being able to truly "Lock Out" Overdrive is a change on the 2005.
Old 12-17-2004, 07:52 PM
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when I pull away from a dead stop in the tow-haul mode I feel what seems to be four shifts,however there's no way a 4 spd .auto can shift four times,so does the converter lock-up feel like a shift or is it the clutch in the auto tranny engaging?? I tow about 7 to 8 k. so I don't know how it would perform under a max gross load.My comparsion was to the 47re ,I've never drove a torqueshift or an allison.
Old 12-18-2004, 07:33 PM
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Hammajamma, the torque converter lock-up (in fourth gear) feels like an extra shift.
Old 12-18-2004, 11:28 PM
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thanks.
Old 01-03-2005, 10:15 AM
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Well if you cant lock out 4th or overdrive gear permanently, the trans is no good ! The first allisons you couldnt lock out overdrive eather, onerdrive being 5th in the allison. Trans was vary poor setup especially for the 8100 gasser, which needed to stay in the allison 4th to keep the rpm right for heavy pull. It did the same thing at 60 she went into overdrive. So if you were in towmode and stayed under 60 it stayed in 4th and pulled well . But you cant hold the speed steady enough to make that work unless you backed down to 55 or less. Trying to hold 58-59 and that thing was hunting 5th all the time. Now GM finally recognised the folly of that and changed the later allisons so if you pushed the towmode once it went into towmode, but if you push the button twice in quik time it went into towmode and the second push locked out 5th or onerdrive permanently. at least untill you reached somthing like 80 mph.
Now you GM boys jump in here and correct me if I'm wrong on this.
Old 01-04-2005, 02:10 AM
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2004.5 tow/haul mode does actually lock out overdrive. I tried it in a dealer truck and vehicle did not shift into OD (75 mph). All I know is what the truck did not do. I like my tow/haul for down hill hauling for it is like a jakebrake (like)


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