Towing in O/D

[KKlepfer]

I was towing a 3000lbs load this week. Drove about 1000mi between 1000 ft elevation and 3500 ft elevation. I would keep it locked out of overdrive when I was driving 60mph or under. My RPM's were around 2500 and EGT's were fine. When I was on the Interstate I would keep it in o/d in order to make time. My cruising speeds were 75mph to 80mph and my egt's were between 300 and 900 depending on elevation and incline. The only time I would take it out of o/d on the interstate was on extreme upgrades that took my EGT's over 900.



My question is: am I damaging my transmission towing in o/d with a moderately light load (3000lbs)? And is 900 degrees too hot to run for extended periods of time?

 

[XJSuperman]

From what I;ve read right here on the board... sounds like your fine.

As long as it;s not shifting into and out of OD frequently. . meaning it will hold itself in OD... you;re not building up enough heat to hurt it.

For the EGT... I'm not too sure as I;m still learning but it sounds like your fine there too.

 

[Blakers]

Have you felt your torque converter clutch slipping yet? That's probably the first thing to go.



When I had my 95 CTD with automatic, I towed our 24 ft TT through the West Virginia turnpike mountains at 70 mph up the hills, in overdrive at 1800 rpm and 1100 egt and 30 psi boost and never slipped a bit. And that truck had 3. 54 gears and 285 tires.

 

[CAKUZ]

Originally posted by KKlepfer

I was towing a 3000lbs load this week.



My question is: am I damaging my transmission towing in o/d with a moderately light load (3000lbs)? And is 900 degrees too hot to run for extended periods of time?

3000 lbs? I would not even consider that a real load for the mighty Cummins. Seriously, I would not take it out of OD for a 3k # load unless I was pulling an extremely steep grade or the engine started running hot on one of Arizona's 'warm' days. 900 deg. turbo temp is OK. If it gets over 1300 deg. you need to make some changes.



I'll be out your way (Cave Creek & Chandler) in 2-3 weeks to pick up my 39',3" Hitchhiker 5th wheel RV. Let me know if you would like to see a Cummins pull a real load.

 

[KKlepfer]

Thanks guys, I suspected I would be laughed off the site calling it a load. It didn't even feel like I had a trailer on it. At times I had to look in the rearview mirror just to see if it was still on hitch.



Thanks for sharing your experiences it gives me peace of mind. CAKUZ, have fun w/ your RV sounds like fun times. We're planning to eventually get a 5th wheel but not as big as the one you've purchased. Thanks again for all your feedback. Bring your shorts and sunscreen we'll probably be in the 90's.

 

[CPritchett]

I pull a 5th wheel that weighs about 11,000 and I almost never have to take it out of overdrive. It runs the transmission cooler locked up about (140degrees than locking out od it will get up to about 170 degrees) I can tow 70 or more if I want to go that fast.

 

[Bob Wagner]

towing with od on is fine as long as you keep the rpm about 1700.



Do not lug the engine while towing in OD

 

[Bfulgham]

CPrichett

Have you had any problems going into OD while towing your trailer? My trailer is not as heavy as yours and sometimes I get up to 65 or 70 before the transmission will go into OD and even then I have to bump the accelerator . I had it flashed once for that problem but it still does it when towing. Shifts good when not towing. Service manager says the transmission is smarter than I am and that it is compensating. But then he also insinuated that automatics weren't for towing!!!! My old 93 cummins auto didn't know that.

Thanks : Bob

 

[jray]

I pull an 8000 lb travel trailer that is close to 10000 lbs when loaded. I like others, mostly tow in overdrive. If I approach a steep hill or grade I lock out the overdrive and slow down just a bit. I find that when I lock out the overdrive the rpm's climb too high for my liking and MPG suffers.



I have to admit that I was skeptical too as to the strength of the 48re but I am pleasantly surprised. So Far I have towed about 5000 miles in overdrive with no problems. The truck has 24000 miles now without a single problem. I have to agree that if you choose to tow in overdrive keep the rpm's up for lubrication purposes. I like to keep the rpm's at around 1900.



I plan on upgrading soon to a triple lock Goerend torque converter.





2003 SWB 3500 305/555 48re slt

 

[CPritchett]

Bfulgham



The only time I have a shift like you describe is towing up hill from a standing start. On a level road it shifts just fine.