Automatic Transmission, How to Use Overdrive

[DonTX]

I have not really "worked" my 3500 much, but will be heading out with my newly acquired fifth wheel soon. I find little information on just how to use the OD button when pulling 13k around. Many say to turn the OD off until you unhook the trailer.

My inclination however is to just pretty much let the automatic features do their thing, keeping the rpms right where the manufacturer wanted them to be, with a little help when and if the EGT's or transmission temps start climbing.

Any guidance from experienced RV'ers? (my truck is in my signature)

 

[JimBob24]

I pulled about 12K with my previous '97. As long as it was fairly level and open road I left OD on. When the trans wanted to shift in and out of OD like slow & go traffic or winding roads where I had to slow frequently for curves than accelerate again I turned the OD off. I never had any problems at all. I did have a Banks Stinger+ and Suncoast TC and VB.

 

[DonTX]

Thanks for that. I am still learning, never heard of the Banks Stinger. Their web site information is quite impressive, what were your impressions of it?

 

[B.G. Smith]

You need to turn the OD off any time you are below 55 mph, 60 is even better, the problem is not the OD but the torque converter, the control pressures in the transmission are too low to secure the lockup in the torque converter at lower rpm's and will cause it to slip/fail(been there, done that with a 99). Also in slow traffic or in town driving I would put OD on if I was running below 45 mph because the torque converter will try to lock up at 35 if OD is off. Probably more shifting than if you had a 6 speed but it saves the converter clutch. And when descending a grade or slowing down you will get a little more engine braking with OD off. bg

 

[JimBob24]

Some folks are not particularly impressed with Banks because they feel they can get better performance for less money and there have been questions about their customer service but I was very satisfied with their stuff back in '97. That is the only Banks I have owned. It seemed to me that Banks designed their products with a concern for protecting the engine.



In '97 the Stinger Plus was a kit consisting of a larger exhaust, less restrictive muffler, less restrictive intake air filter (K & N), larger TC exhaust housing, redesigned wastegate actuator and modified throttle plate . The kit also came with pyro and boost gauges. For me the kit transformed my stock truck from very marginal to completely acceptable as a tow vehicle. There was no problem with EGT'S either. In fact, it didn't take too long to overwhelm my rather weak stock TC on the 47RE, so I installed a Suncoast tripple clutch TC and upgraded VB. It was no sled puller but a very good tow vehicle for my 12K fifth-wheel. I also had the Banks exhaust brake on that vehicle and it also worked very well.

 

[JimBob24]

You need to turn the OD off any time you are below 55 mph, 60 is even better, the problem is not the OD but the torque converter, the control pressures in the transmission are too low to secure the lockup in the torque converter and will cause it to slip/fail(been there, done that with a 99). Also descending a grade or slowing down you will get a little more engine braking with OD off. bg

B. G. is right about the trans. line pressure. The Banks Stinger kit I used also had a device to increase line pressure and I still burned the clutch in my stock TC. I think as long as you can maintain highway speeds without a lot of throttle then OD on is fine, but under the conditions requiring a lot of pedal causing the TC to slip you need to turn OD off.

 

[y-knot]

We both have the same year trucks, and I have owned mine since I ordered it in 05-06. love the truck, but the stock transmission is way to weak for a 3500. I had mine go out at around 38K miles, and after only towing less then 3500 miles. After replacing with an ATS unit, the truck is plain assume. I tow a 16K lb trailer and have no troubles.

Out on the highway, running 65-75 mph I like to leave the trany in OD, even on most big hills it does just fine. The trick is to leave the OD OFF around town and in stop and go traffic. It really helps keep the trany cooler and saves the wear and tear of the OD unit constantly engaging and dis-engaging. The best thing you could do to keep the transmission alive and healthy is to install a good trany cooler like the one I offer from

www.proweldperformanceparts.com . They really keep the temps down and will prolong your transmission health and even help with shifting and operating performance. Good luck on the new trailer.

 

[cwsoules]

My transmission has been upgraded by DTT and I have their Smart Box too. My smart box keeps the transmission in 3rd until 57mph where the torque is OK. It then shifts to OD. I watch the speed and egt and disconnect the cruise control and shift out of OD as necessary to keep the egt at or below 1250 and keep the transmission from hunting in and out of od. It works for me.