OVERDRIVE or NOT WHEN TOWING???????

[anthony4]

I had one Quick question to all you Trailer towing diesel trucks???? I pull a 35 ft 5th wheel about 9000# Is it okay to tow on the freeway 65-70 miles per/hr on a normal grade in overdrive????? and if you see a change in the grade going up is it okay to turn overdrive off????? and can you down shift to 2nd gear??????


2001 2500HD Quad Cab SLT LWB, 4x4, Cummins, 3. 54 gears,
Deep Garnet Red, Agate, 4w ABS, tinted windows,
Camper and Trailer tow packages with trailer towing mirrors,
HD transfer case, snow plow prep, cab lights, travel conv group,
mopar nurf bars, Downey SST cover, Bed liner with fifth wheel hitch
Power driver seat with power lumbar,
loaded loaded loaded!!!!!!!

 

[B.G. Smith]

You could get as many different replies to this as there are TDR members but here is mine from 56000 miles of experience, most of it towing a 31' 5th wheel (which weighs 12400#) First, if your 35' 5th wheel weighs 9000# I want to know what brand it is and how do you get your wife to leave all the stuff at home. I tow in OD any where I can maintain 65+ mph. , started out locking out OD when I would hit a grade but have found that the transmission does a much more efficient job of downshifting than I can, just stay on the accelerator. Going up grade it will get in second automatically if the need arises, going down a steep grade, such as Wolf Creek Pass in Colorado, I slow down and manually shift into second and lock out the OD before starting the descent. bg

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White 99 3500, QC, 3:55, auto. most options except leather, Line-X bed liner, fiberglass running boards Rancho 9000s, bug shield and window vents, black vented 5th wheel tailgate, 110 gal. aux. fuel tank.

[This message has been edited by B. G. Smith (edited 04-16-2001). ]

 

[Joe G.]

BG has it right! The only thing I would add is that an EGT gage is a good idea so you can keep an eye on the temps.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,DTT TC/VB,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

[Fireman Dave]

I just got back from my first trip with my new TT. It weighs in at somewhere around 6,000 lbs. I found that I liked OD off much better than on. It seemed like being under 2,000 rpms was too low. I just liked the feel of being over 2k - more responsive, and the truck seemed happier there. I was between 50-65 mph most of the time. It was very windy, too. Also, I'm not sure it was downshifting when it should even with OD off on some hills - seemed to be lugging more than it should at times. I'll see the dealer about this - may need a reflash? It was fine most of the time. I'm still getting used to it. This first trip was just a couple of hundred miles.

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2001 2500; SLT; 4x4; QC; LWB; Auto; 3. 54 LS; 265s; Camper; Tow; Sliding Rear Window; Travel Convenience Group; Cab Clearance Lamps; BedRug; Forest Green; Isspro Pyro, Boost, and Trans Temp Gauges; 27' TT

 

[Guest00]

You probably need to adj the trans detent cable. The adjstment is made at the cable support under the (tps) cover.
see your service manual.

 

[Ramboy00]

Bill K recommends,with his TC,not going into o. d. till you reach 60 m. p. h. when towing.

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'99 D3500, auto. ,2WD,3. 55 LSD, all options, Banks Power Pack w/K&N filter,DTT TC & VB, Mag-Hytec pan, '99 40ft. Alfa Gold Triple-slide 5'er

 

[JyRO]

B. G. - I don't have an auto, but I'm curious about them cause I'd imagine that if we could ever get an Allison, I would consider going auto. My question: When you were talking about decending steeper grades, you mentioned pulling the truck into 2nd gear, and locking out the overdrive.

If you pulled the gear selector into second gear, isn't the OD "locked out" already because of the gear selector location?

Or does pushing the button (O/D on/off) make some sort of difference even with the gear selector in 2nd gear?

I've always wondered if the button (O/D on/off) made any difference to the transmission in a gear other than Drive. Please let me know and thanks.

- JyRO

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Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 LSD, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock engine, silencer ring removed, "stealth," mod to run fogs with high beam. (20. 8 mpg @ 70 mph) Since everybody else listed their toys, I will too.

2000 Toyota 4Runner SR5 4X4, 5-speed, 3. 4L V6 (25. 5 mpg @ 65 mph)
1990 Toyota Celica STX, FWD, 5-speed, 1. 6L I4 (36+ mpg @ 65 mph)
1983 Mazda RX-7 GSL Limited Edition RWD, 5-speed, 1. 1L Wankel (For sale)
No auto trannies in my home! Just say, "No!" to auto trannies.

 

[brobeson]

I too have a 98. 5 24v, Auto and tow a 35er, but mine weighs about 14000#. I am 21000-22000# across the scales.

As the owner’s manual says, I tow in OD all the time. In the hills, I will hold in out of OD to keep it from shifting up and down, but other than that, let it run in OD.

I have 4. 10's and 285 tires, so I run about 10% faster than my Odometer, but at about 55mph, I will sometimes manually drop it out of OD before it does to help keep up my speed. It will drop out of OD about 50mph on its own.

Never let the trany down shift, then up shift, then down shift as this will kill your trany very fast. In some mountains I have to hold it in 2nd at 45mph as I can not climb the mountain in 3rd. But in 2nd it just wants to accelerate then shift into 3rd, which can’t pull the mountain, so it down shifts into 2nd. This is BAD. I just hold it in 2nd, cruise up the mountain at 45 mph.

Good luck.

Bob


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1998. 5, 2500, SLT, 24V, 4X4, Auto, 4. 10 towing 35ft. 5er
On Order due May 1. 3500, SLT+, Green/Tan, HO, 6 speed, 4X4, 4. 10, towing package, camper package, E-brakes.

 

[B.G. Smith]

JyRO, I think you are correct in that the OD off switch only has an effect if the transmission is in D. bg

 

[SlyBones]

From what I thought I saw Bill K. post you can run in OD as long as you keep at least 1700RPM when towing. Correct me if I mis-quote him. I guessing it has to do with the health of the transmission.

I find my auto wont downshift out of OD until the speed drops below 50MPH which is too low an RPM according to the above rule. So I generally keep it in OD until the RPM's drop to 1750 mark on the tach, then I lift off the throttle, push the button, and floor it. This generally hits the right RPM for 3rd. Waiting too long I dont get enough R's in third, not to mention I assume its hard on the transmission. Or when I have to run around 50-60 then I always lock out the OD until the speed picks up.

The real solution of course is BOMBing. Get enought HP so you can always stay above 1700 even on the hills.

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1997 2500 4x4, CC, Auto, 3. 54 LSD, 68K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Molded Side Steps w/ Ground Effects, Chrome Trim, Canopy, ProFlaps F&R, BedLiner, Aux. Lighting F&R, and tons more.

 

[Hale on wheels]

My truck has a hard time towing only about 6500-7000 pounds in OD, so I keep it in 3rd at 2500RPM. That is 65 mph and right about a good speed to tow. Maybe my truck is a dog, since some of you say yours can pull in OD, I think it is time for an EZ #ad


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Cody Hale
01. 5 2500, QC, 4x4,Auto
Gig'em Aggies!

 

[samb]

I also tow in OD and my truck will kick out of OD at 60 mph. If I just have a short distance to get over the hill I just leave it in OD but if the hill is long where the truck will up shift before I get to the top I will punch the button and keep it out of Od until I top the hill. I also do most my towing in cruise control and it works great and I am all stock.
Sam B.

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97, Lamanie SLT, clubcab, driftwood, 3. 5 spicer 70 rear axle
96 Coachmen Royal 285rk 5th wheel, 11,000 #

 

[FirstDiesel]

I pull a lighter load, 4500-5500lbs, (car trailer and race car) and have no problem pulling OD as long as I can keep the revs up over 1600-1700. I've noticed a power band that kicks in around the same. 1600 rpm is around 57MPH. At 2000-2200rpm the diesel really pulls hard. This is 70-75MPH. I have no trouble blasting down the interstate in the left lane. I very seldom pull into 2nd. Although, one thing I've noticed is that accelerating a diesel is very different than accelerating a gasser. With a gasser, you put your foot into it and kick down to a lower gear. With the diesel, I can actually feel better acceleration by feathering off the pedal around 55MPh (kind of a false clutching action) and letting the OD slide in and TC lock, and then getting back into the pedal. This puts the revs at the low part of the power band. It pulls right out. Like BROBESON says, never let the transmission shift back and forth. This is my first Chrysler OD, but Ive worked on Chevy 700R4's and Ford AOD's. The weak link in both of them is always the OD clutch pack. Although you do not want a neck snapping shift when towing heavy (high shock loads to trans and drivetrain), I think the factory errors to the slush-o-matic side (thus burnt OD clutch pack). I am thinking my first BOMB is a shift improver since my loads are relatively light and trans temp gauge.

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<i>Brian</i>
2001 Quad Cab, 2500, 4x4, SB, Auto, White

 

[BigDaddy]

I can not comment on the downshift to 2nd however, empty, bed loaded, or towing I follow this advise:
Bill K said in ”Trans Talk”, “Towing in od is not a problem, towing in od at low rpms is a big problem... Just keep in mind when you have to make a choice between towing in od in low rpms or drive in high rpms, choose drive at high rpms.

Bill K said in Trans Talk,
“ I do not like to see od being used below 1500rpms when empty. 1700rpms when towing heavy. ”

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<font color=forestgreen>2000</font> DODGE <font color=forestgreen>RAM</font>, <font color=forestgreen>2500 HD</font>, 4x4 SLT, Reg. Cab, <font color=forestgreen>Forest Green</font>, Agate interior, Cummins ISB, Auto, Shift-on-the-Fly (241HD), 4. 10 LS, ABS, Trailer Tow Group, Camper Group, Michelin; DC: Fog Lights Kit, Tow Rings, Under Rail Bedliner, VentVisors, Splash Guards, Cold Weather Cover, & Mats.
<font color=forestgreen>After-market</font>: JRE 4" Exhaust, Van Aaken, High Idler, Heavy Duty Idler Pulley, Gatorback Belt, Painless Wiring, K40, Viper w/AutoStart, Clarion 6 Disk CD w/remote, UnidenCB w/Francis antenna, Draw-Tite Activator II, Alpex 255TC2C Air Horns, Continental BedRails, Delo 400, HOWES, Liquid Glass.

BigDaddy's Ram #ad
New England RamRiggers

<font color=36648B>2001 PT Cruiser Limited Edition</font>

 

[SHOOT1SAM]

"going down a steep grade, such as Wolf Creek Pass in Colorado, I slow down and manually shift into second and lock out the OD before starting the descent. bg"

B. G. : Is your transmission stock? I was under the impression that manually down shifting into 2nd did not lock up the torque converter and slippage/overheating would happen pretty quickly. The ability to lock up the t/c seems to be one of the highlights all of the aftermarket transmission parts companies. Am I confused?

 

[Joe G.]

No Sam, you are not confused. The stock TC will slip a lot in 2nd and the temp can get quite high. The DTT vb does allow the TCC to be locked in 2nd. You can use a manual lockup switch (mystery switch) to make the lock. The user of the switch must know what they are doing and know the limitations of using the switch.

 

[JyRO]

Yeah but..... correct me if I'm wrong here, even with a stock auto transmission, pulled into 2nd gear and slipping like an auto transmission slips, it wouldn't get hot going down hill, would it? I mean, its not working all that hard, not like it would be if a stock transmission was pulled into 2nd and going up a grade. Then it would get hot, fast.

Down hill your safe (on transmission temp), aren't ya?

- JyRO

 

[B.G. Smith]

SHOOT1SAM, stock trans. , I don't have a temp gage on transmission but I haven't had any heat related problems, 56000 miles. JyRO, I too, have a hard time believing a transmission will be ok going up a grade with a sizeable load and then burn up going down the other side. I don't have a lock up switch either. This has been beat to death before and the reasoning was that the torque converter won't be lock in 2nd and will generate tremendous heat, well it's not lock going up either, it will lock in 3rd under moderate throttle but I can't pull Wolf Ceek pass at moderate throttle, it's pedal to the metal.

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White 99 3500, QC, 3:55, auto. most options except leather, Line-X bed liner, fiberglass running boards Rancho 9000s, bug shield and window vents, black vented 5th wheel tailgate, 110 gal. aux. fuel tank.

 

[MCrossley]

I am not the transmission expert (Bill is) but actually from what I understand is yes you will actually build heat quicker going down a hard grade in just second gear a) because your line presure is low (no throttle = idle trans pressure) and B) low air movement across the cooler at <20MPH. I hope Bill will step in soon to answer these questions.

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TAZ... 2001 2500 SLT+ 4X4 Auto ETC Cummins, LSD 3. 54,Quad Cab, Long Bed, Agate Leather, White/Driftwood Exterior, Sliding rear window, Camper Special Group, Towing Group, Cab clearance lights,SPA-Technique Digital Dual Gauges (Pyro/Boost, Trans pressure/temp) Aux. Backup lamps. BNM 5th Wheel Hitch, Additional Body Molding on Bed. Line-X bed-liner. DTT's TC & VB, Pac Brake, Power Edge, Edge EZ, Grover Air Horns

2000 32' Aljo Triple Slide 5th Wheel.

http://www.ramtaz.com

Add on's to come: any other Ram Runner required modifications...

 

[fmj]

When towing I leave it out of OD so I can keep up the RPMs. The ETGs are easier to control while pulling a hill. Here in California the speed limit while towing is 55, so this keeps me between 60 and 65 with no tickets (3:55 gears). I have a tag-a-long that is a little over 6000. The trailer hauls a 41' Willys Coupe and going faster seems to me to ask for too much tire heat and possible blow out. All I can picture is the front tire of the tandem going out and taking the rear tire out with disasterous results. So its not that I can't go faster, but a peace of mind issue. My trany temps stay around 150 until pulling a grade. On a steep grade it reaches 170, which I think is safe. What do you guys mean when you talk about "high" temps? Another question is when the trans starts going will I see temps increase before the trans goes south? I whatch the ETG and trans temps closely. Knowing what is normal now, I would assume that an increase in temps on the trans would indicate problems comming.