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Towing With 1995 RAM 2500 5.9L 2x4 Laredo, AutoTrans- Your Advice, Please

My transmission just “gave up” while towing a 7x16 enclosed v-nosed two axle 8,000lb trailer down the interstate. I’ve just paid $1,300 to have it rebuilt, and I do NOT want to make mistakes in the future that will cause this to happen again! I did not exceed 65mph and it gave up about 300 miles into the trip- engine has 127K miles and burns ZERO oil… just had plugs and wires replaced. While driving on relatively level Interstate, I keep the OD on and the RPMS are around 2,200. However, on inclines the vehicle downshifts to 3rd (I think its 3rd, anyway) and RPMS jump to 3,400 or so. Many have told me that OD should be OFF while towing, but the truck never makes it out of 3rd gear if I turn it off. During “regular” driving, the OD seems to drop the RPMS from about 2,400 to about 2,000. Trailering long distance at 3,400rpm seems wrong… too high. Shouldn’t the transmission drop to the 2,400rpm range if OD is off, rather than stay “stuck” in the lower gear? Also, when tranny died it seemed the separate radiator for fluid wasn’t very warm at all… but there was PLENTY of fluid in there. That fluid NEVER smelled burned or discolored in my years of trailering this way. Can you guess what went wrong this trip? How SHOULD the auto trans be used while trailering? Seriously, I can’t afford for this to happen again!!

My opinion is that if you’re towing, or even hauling a load, overdrive needs to be OFF.

Yep, OD off, hard on the transmission otherwise, you’ll burn more gas with the OD off, but might have saved the transmission. Maybe.

What is your Dodge rated to tow?

All tow vehicles that I have used or know of that are tow rated to 10k lbs or more, say…do not use OD while towing. 8k lbs is substantial enough, even for a 3/4 ton to be considered significant. I towed a light tractor on a flat bed which was less then 7500lbs with a HD dump truck with a 20k rating and the boss said to me “take it out of OD” . I was regardless but this is from the guy who buys and repairs the trucks. If I were you, I would listen as now that’s you. If you don’t like your rpm and mileage while driving 65, that tells you, you should be driving 55.
Besides, the truck had over 100 k miles. It could go regardless. So don’t help it. Btw, how many times have you service your transmission in a vehicle used for towing over that 127k miles ?

I’m in agreement here. Never tow anything with the OD on. Most, if not all, owner’s manuals tell you to turn off the OD when towing.

In addition do you have a transmission fluid cooler, usually included in a tow package. If not add one. Mine says if there is excessive gear shifting do not use od.

I have a Ford Explorer with a tow package, including an external transmission fluid cooler and appropriate gearing in the rear axle. The owner’s manual says to turn OD off when towing, and I do just that. My mileage drops from 20 mpg to 15 with OD off, but my transmission now has 250,000 original miles on it.

Yep, I think thats basically what the tow position does on most shifters I’ve seen,the engine is lugging and struggling to keep the speed up in OD,so the tranny slips more and generates more heat,the towing package most manus offer is a fairly good deal,but some of thier oil coolers seem to be bit skimpy,so run with the OD off when towing a hefty load(even if you are hauling a good load in the bed by itself) besides you will tend to run at a more controllable speed-Kevin

$1300 seem pretty cheap for the rebuild, did you tell the shop what you tow ? They might have been able to beef it up some for only a few hundred more.

$1300 for a rebuilt transmission? Including installation? That price scares me, it’s too low for quality work, at least in my part of the country.

Never tow in overdrive. Of course the trans never makes it out of 3rd gear when OD is off, that’s the idea, to keep it in 3rd. Make sure you have an external transmission oil cooler.

Driving long distances at 3400rpm may be a bit hard on the engine, but with a good heavy duty cooling system, good clean oil it shouldn’t be an issue. Engines are made to work.

How long have you been towing this trailer? Frankly, if it were me towing 8,000 lbs long-haul regularly I’d be using a diesel.

Maybe this rebuild was one of those “soft” rebuilds with clutch packs and seals only; no torque converter, no new solenoid pack, no update parts, bushings, etc.

The owner’s manual says some things about towing. Most of them say the same things. You could borrow one if you don’t have the one for your truck and go over it.

The TV commercials say that you can drag race with 10,000 pounds towed. They don’t fill in all the details about whether you should. The owner’s manual fills in some of the details but none of them say to tow at 65 MPH like you’re driving an empty Corolla. You may even ask yourself how you plan to stop 12,000 pounds from 65 MPH. Sometimes you can’t!

Really, we should have the CVT if we want to tow. Clutch-Verybig-Truck.

“Maybe this rebuild was one of those “soft” rebuilds with clutch packs and seals only; no torque converter, no new solenoid pack, no update parts, bushings, etc.”

Yeah, that’s what I was afraid of. If that is indeed the case, seems like false economy to patch up a 20 year old trans with 127,000 miles and not do a good heavy duty overhaul. Especially if it’s towing 8,000#.


If I were you, I would listen as now that's you. If you don't like your rpm and mileage while driving 65, that tells you, you should be driving 55.

Remember that other thread, many people scolded me for only going 5 over the speed limit saying I was holding up traffic telling me I should go as fast as it takes to get people off my bumper because I was holding up the flow of traffic.

Now your telling this guy to go 55 on the interstate? Blasphemy!! He will disturb the “flow”. I got places to go and people to see, My destination is much more important than this guy trying to safely tow something.

If he cant tool along the highway going at least 20 over he shouldn’t be on the road. That’s what I have learned from here.

I pity your teachers if that is truly what you learned from those exchanges. Multiple times people tried to drill through that apparently thick skull that no one was referring to trucks using the right lanes as they should. No one can be so dense, it has to be someone looking for attention in any way they can. I apologize to everyone else for feeding the troll but this is ridiculous…

A transmission cooler and regular fluid changes are the best things you could do for your transmission if you tow. Leave O/D off. You towed a heavy load with O/D on, with a transmission that had over 100K on it and was maybe never serviced. That’s probably what killed it–age, old fluid, and lack of cooling.

The 5.9L engine is a tough old bird. If you keep good oil in it (I’d use synthetic) and watch the temp gauge, it shouldn’t have any problem with the tow. Your gas mileage will likely be pretty miserable though.

Now that the truck is repaired and operational again, I’d check the transmission oil cooler. It should be very hot after an hour of towing 8000 lbs. I suspect the cooler is clogged or an oil line is kinked, or something is reducing the flow. On marine transmissions it is standard to replace the oil cooler after a tranny failure. Debris from the old failed tranny can clog the cooler.

If in doubt I’d replace the oil cooler with a new one, and install new oil lines too. I think your current oil cooler isn’t doing its job and your failure could go back to overheated fluid. Since it is an old truck that oil cooler could have been inefficient for some time.

Well on the subject of towing I have a friend who pulled a 17’ or so 5th wheel trailer with a 6cyl Ford -150(bet that looked an ant pulling a Katydid) He got where He was going,but He had a manual transmission,but He was used to driving rigs that weighed in excess of 100K,finally He ended up with a Diesel Dodge,I agree with the poster that says a clutch is better for heavy towing on light vehicles,but dont rule the Allison autos out they are designed to tow.
On the subject of rebuilds when we went through an auto transmission on caterpillars,we always replaced the oil cooler and torque convertor(its prudent,because it prevents a lot of recontamination in the system)-Kevin

I would install a big auxiliary transmission temperature gauge. I think automatic transmissions start melting down about 300 degrees.