|
|
08-04-2008, 11:00 AM
|
#21
|
Montana Master
Join Date: Jul 2005
Location: Fort Myers
Posts: 5,933
M.O.C. #4282
|
Yes, I meant 1,950 rpms. Manufacture, dealer, most here on the MOC, recommend Tow Haul mode at all times when pulling. It does not increase your rpms, just shifts different to give the trans optimum power and cooling. I ran once with tow haul off for a while and the trans temp started creeping up too high for my comfort.
Remember, I do have the older 5 sp Allison (2002). Maybe you can get away with not running TH while pulling with a 6 speed, but I have to trust Allison to "idiot proof" my driving...
|
|
|
08-04-2008, 11:40 AM
|
#22
|
Montana Master
Join Date: Aug 2008
Location: Shelburne
Posts: 688
M.O.C. #8693
|
Several times, on the flat, 95KPH, (about 60MPH) I've switched out of tow/haul. The RPM's immediately drop by two or three hundred. I'll record the value more precisely next time and pay close attention to the transmission temperature. I do monitor the temp if we've been climbing a lot, but I always engage T/H for those conditions.
|
|
|
08-04-2008, 11:52 AM
|
#23
|
Montana Master
Join Date: Nov 2007
Location: Kville
Posts: 2,865
M.O.C. #7871
|
Quote:
quote:Originally posted by Snownyet
Quote:
quote:Originally posted by KathyandDave
You said: I also run 62-63 mph @ 19.5K RPM, always Tow Haul with the Monty.
Did you mean 1.95K RPM? Why always Tow/Haul? It increases the RPM, which suggests that fuel consumption is increased. In our admittedly brief experience, on flat terrain, the ordinary gearing pulls well at lower RPMs. We're using the T/H only for grades and leaving it on for hilly terrain. Are we missing something?
|
Tow haul increases the rpms that the transmission shifts at as you accelerate. When crusing down the road at 60 my rpms are the same in both tow haul and regular mode. Plus using tow haul activates the grade braking feature on newer trucks.
|
GM says to use the T/H if your GCW is 75% or more than the GCWR.
|
|
|
08-06-2008, 04:17 AM
|
#24
|
Montana Master
Join Date: Nov 2002
Location: Oceanside
Posts: 20,028
M.O.C. #20
|
Quote:
quote:Originally posted by dsprik
My 2002 is a LB7. I thought about changing out my trans fluid to try to combat this temp spike, but I was told that you cannot change it all out at the same time? Only 6 or so qts out of the 22 qts? Have not checked with a dealership though on this. I do keep my spin on filter changed at regular intervals.
|
Dave, most of the oil is in the torque converter. Most torque converters have no drain plug and thus when they change transmission oil they're changing only what's in the pan. That oil in the torque converter then mixes with the new oil as it circulates.
If I'm not mistaken, they can flush out all the oil using a different method other than just drain and fill. Then they can fill with all new oil. It's obviously more expensive to do this but sure cheaper than a new transmission.
I need to take another look at the manual for my Dodge. I seem to recall it said transmission oil changes should be done at either 60k or 75k, even with severe service. That seems a long time to me. My Dodge has 35k on it now so I may go ahead and have the transmission oil and filter changed out soon.
|
|
|
08-06-2008, 04:47 AM
|
#25
|
Montana Master
Join Date: Jul 2005
Location: Fort Myers
Posts: 5,933
M.O.C. #4282
|
Thanks for the clarification, Steve.
|
|
|
08-06-2008, 05:44 AM
|
#26
|
Montana Master
Join Date: Jul 2003
Location: Clearwater
Posts: 10,917
M.O.C. #420
|
When towing I run 80 in the rear and 65 in the front. When not towing I run 65 front and rear but I only lower the rear air pressure if I'm not towing for a week or more. I run 30 to 40 in the air bags while towing and 5 when not towing.
As far as Tow/Haul, I only use T/H on grades or when slowing down for a rest area or traffic. Never on a flat hiway. On a flat hiway I also tow in Over Drive and in Cruise Control and again only shift out of OD on grades or when slowing. Argue all you want but T/H does increase RPMs thus decreasing MPG. The longer the tranny takes to shift the higher the RPMs. The higher the RPMs the less MPG. You can not only see the RPM increase on the tach but I can hear it as well.
RPMs increase, Fuel mileage decreases. That is a fact of life.
This is my 2nd Duramax and only one time did I ever experience an overheat problem and that occured on a very long grade on a very hot and humid afternoon. And yes, I was on T/H for that grade.
|
|
|
08-06-2008, 02:09 PM
|
#27
|
Montana Master
Join Date: Nov 2007
Location: Kville
Posts: 2,865
M.O.C. #7871
|
True, the T/H extends shift points when accelerating...that's what it is there for and designed to do. But once in the next gear, it runs the same rpm as if not in the T/H.
|
|
|
08-08-2008, 04:55 AM
|
#28
|
Montana Master
Join Date: Aug 2006
Location: merced
Posts: 983
M.O.C. #6171
|
Kathy and Dave
I have it mounted on both frame rails and I have cross braces at rear and about four foot in to help eliminate some of the twisting on the frame. as for bounce on bumpy roads, had it with or with out the bike on rear. Bike wieghts about 300Lbs, I don't know if you are familiar with the 3000RKs but they have to much pin wieght any way.
|
|
|
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|