I haul RVs from Elkhart, Indiana throughout the U.S. Half my time the truck is towing an RV and half the time I am driving deadhead back to the terminal to pick up another load. I have been changing my oil about every 5000 to 6000 miles. Is this about right? Can I stretch this out to every 7000? Every 8000?<br><br>Second question. While under load with a heavy trailer, the engine wants to shift out of OD so frequently that I manually press the OD button to lock it out of overdrive. I assume that this constant shifting in and out of OD is not good for the transmission. While out of OD I do about 55 miles an hour at 2000 RPM. If I drive any faster it “feels” like the RPMs are too high. How high can I run the RPMs without damaging the engine?<br><br>I am a first time diesel owner.<br><br>Thanks.<br><br><br><br>

 

For starters the Cummins was engineered to run at or near redline for looooong periods of time. You won't damage it that way but your MPG will suffer.<br>Have you thought about an aftermarket &quot;Gear-Splitter&quot; like the Gear Vendors overdrive to reduce RPM?<br><br>Going with a synthetic oil and a By-Pass oil filter system will allow you to go further between oil changes.<br>Also sending an oil sample for analysis will help to determine if you can go father on the oil in the engine.<br><br>HTH

 

I'm not sure but I think the frequency was moved to 15000 miles but that may be on the 03's.<br><br>I ran dino oil in my old 89 up to 85000 miles and I ran it 10,000 miles changing oil filters every 5000. With the type of driving you are doing, personally I believe it would not be a problem.<br><br>You could also consider going to some type of synthetic with a dual remote system and extending change frequency that way. I switched to synthetic in my 89 at 85000 miles and ran the same oil for 4 1/2 years with oil analysis.

 

[quote author=dieseldude4x4 link=board=11;threadid=11070;start=0#105604 date=1045484785]<br>I'm not sure but I think the frequency was moved to 15000 miles but that may be on the 03's.<br><br>[/quote]<br><br>15000 is when you never drive your truck. ??? ??? I know, kinda silly, but the specs on a 15000 oil change are no short trips, no hauling, no nothing, everything in a perfect world. Otherwise, 7500 is the number. This is for the 2003. I think everyone I have heard about on this forum is the 7500 bracket.

 

I sorta thought 15000 was kinda extreme. I have however run Rotella 10,000 miles in my two older trucks changing the oil filter at 5000.

 

I read of guys who pull with 4.10 gears at around 2500 rpm all the time. And I did hear that the 24v is a high rpm diesel, just not efficient at those numbers. I go 7500 between changes too.

 

With my 4:10's and my 5spd I don't mind taking the RPM's above 2,500 when pulling a load. <br><br>As was stated before and what a Cummins Tech told me, &quot; These engines have no problem running full throttle 24-7&quot; They use these motors in pump houses and they run for months without being shut down and near red line. 8) So 2,500rpm's for 12 hours won't even fase these bad boys. ;D<br><br>DB

 

[quote author=twhite link=board=11;threadid=11070;start=0#105586 date=1045482068]<br>I haul RVs from Elkhart, Indiana throughout the U.S. Half my time the truck is towing an RV and half the time I am driving deadhead back to the terminal to pick up another load. I have been changing my oil about every 5000 to 6000 miles. Is this about right? Can I stretch this out to every 7000? Every 8000?<br><br>Second question. While under load with a heavy trailer, the engine wants to shift out of OD so frequently that I manually press the OD button to lock it out of overdrive. I assume that this constant shifting in and out of OD is not good for the transmission. While out of OD I do about 55 miles an hour at 2000 RPM. If I drive any faster it “feels” like the RPMs are too high. How high can I run the RPMs without damaging the engine?<br><br>I am a first time diesel owner.<br><br>Thanks.<br><br><br><br><br>[/quote]<br><br>twhite <br><br>A good way to extend your oil changes would be to start oil sampling this will give a good indicator of whats happening to your CTD...by using a quantity oil and filters you should be able to change oil every 8-9000 miles by watching the sampling reports<br><br>The shifting out of OD is controlled by the tranny and tranny pressures....when this happens most times your dropping RPM's and lugging the motor (like climbing hills) you can install a torque converter lockup switch...then you control the lockup but be careful so you don't overheat your tranny or lug the engine....the lockup switch works good for me since my normal loads run heavy 18-20000 lbs just remember to unlock before coming to a stop<br><br>Torque Converter Lock-up Switch Installation<br>http://www.tstproducts.com/tranny_install.html