I have a 2001 grand Cherokee with a 4.0 and will be towing a two place trailer and two ATVs.............should I have O/D on or off while towing?


Thanks,


RIZ

 

Riz, I would suggest not using O/D when towing because of the load on the trans. Remember that O/D gear ratio is .75 to 1 and 3rd is direct 1 to 1. 185 horses don't go very far when overdriven. Besides that, it will be kicking in and out of lock-up and toasting the torque converter clutch.

 

The overdrive clutch pack has fewer clutches than the other gears, so you won't want to use overdrive while towing through hills and mountains. Flat highway driving may not hurt to be in overdrive while towing. If you can feel the trailer behind you, you should probably keep it out of OD.

 

x2 Especially if you do not have the tow package. W/O tow package your axle ratio is 3:55 compared to 3:73 with the tow package. The 4.0 lugs in and out of OD enough anyway...towing will take it over the edge. I turn my OD off on hilly terrain towing or not.

 

Get a good size tranny cooler. Heat kills automatic transmissions and towing in overdrive generates a lot of it.

 

I just got back from towing my two ATVs 32 miles to get tuned up and I had my O/D turned off and I was running at about 2900-3000 rpm at 70 mph. Is that about right? On the drive back home with no trailer IN O/D I was pulling about 2000-2100 rpm at 70 mph.


RIZ

 

That is the point of overdrive, it lowers the engine rpm for better fuel mileage.

 

Yup, you have the 3:55 ratio

 

-

Just got back from Sturgeon Bay WI about 300 miles each way towing a 3500lb Ranger walleye rig, trailers about 1500... On an 01 WJ Overlander 47 with 108k I always when towing push the button on the side of the stick and take it off of OD and I also was about 3k RPM. I was thought a long time ago to do that. I'm glad its the right thing to do.

I'm still a little confused by the gear ratios, Torque Coverters and diff gears... Whats it on my trans/diff? Is there an easy way to understand it 3:55 Vs. 3:75 etc. ?

Thank you for helping me understand it better.

PeterB.

-

 

Towing at 70 mph?

 

Yeah, you noticed that too? Riz, think about how fast those small trailer tires are turning. Have you checked the bearings lately?

Does anybody know why U-Haul limits their trailers to 55 mph? It's because they won't cover any damages done to the vehicle OR trailer if towed at higher speeds.

Peter, you're towing more weight than your tow vehicle. It's very easy to lose control at 70. That's all I'm going to say on that subject.

 

-

Well I cruised controlled it at 65 but occasionally when I had to pass a slower moving vehice I may have gone close to 70. I try not do that, even though their very well built, solid and sturdy. If I hit a wind blast from say a semi my trailer may sways a little. I then ease off and steady as she goes then.

Thinking about your statement I agree wholeheartedly and will keep in mind in the future not to go over 65.

Thank you Dave I appreciate the heads up.

PeterB.

PS. My Ranger trailer has the oil Vs the grease type bearing buddys type. I service it every few years... Is that acceptable?

-


-