6.0/3.73/6speed in mountains pulling 8000 lbs

[sportsman16]

I have 2013 suburban 2500 pulling my new Creekside 27 bh which is 8,000 loaded. First trip with this combo over Stevens pass hwy 2 in Washington state. Once the serious climbing started I was 2nd gear at 4500 rpm to hold 45 mph. Transmission temp started at 190 and hit 235 at top of pAss. TranS temp dropped quickly down the other side. I was afraid to move my foot on the gas. Any more throttle and I may have dropped to first. Any less and it would have shifted to third and speed would have lugged. I hear plenty of folks that pull heavier with this combo, how? I always read about letting these engines rev to hit max power, am I doing something wrong? Trams temp of 235 startled me a bit. Is there a better way to approach the pull up the mountain passes ?

[NWKomfort350]

I towed Stevens pass with rig in sig in July. We hit the summit at about 42 mph, and tranny was 230-235. It peaked around 238 for approximately 30 seconds. It was closed when we headed home due to forest fires. We crossed Blewitt and Snoqualmie (90)on the way home, and never got above 210 degrees in the tranny.

[JustLabs]

Stevens Pass is no joke,especially eastbound

You're doing fine IMO.

[ls1mike]

You are fine. I have towed Tiger Mountain, Stevens Pass, Vantage, Snoqualime, 4th of July, Look out pass and a bunch more with my 02. I would see 235 sometimes. I didn't like that so for 100 bucks I put a bigger plate cooler on it. This summer Tiger Mountain, Stevens Pass and vantage going 40 to 60 mph trans temp never exceeded 210. My trailer is just about 7500 lbs loaded.
4 speed 4.10s.

[hawkeye-08]

I notice when my transmission temp goes much above 210, the engine coolant temp rises also.. on a hot day a few years ago on Sherman pass in north central Washington, engine and trans temps were both around 235 for a few miles hear the top. They stabilized (weren't climbing) and cooled down immediately after cresting the summit.

[wintersun]

235 degrees for the ATF is not going to cause any problems. The temp rises because you have less air going through the cooler fins at 45 MPH but due to the grade there is still a lot of heat being generated inside the transmission. At higher elevations there is also less air and this does not help the situation. All you need to do is be sure that the ATF level is not low.

For pulling a load up a grade I would keep the engine at the RPM's where it produces maximum torque and not maximum horsepower.

As you noticed the ATF temperature quickly dropped after you reached the top of the grade and that is all you want to see. At least you know the trans fluid temp should reach 232 degrees in that situation so if in the future you see it going a lot higher you will know something is wrong.

[blt2ski]

THere can be a lot of slow twucks on these steeper grades, or one figures out how to go around them. Sometimes, one can not just go around per say.

As I have said before, I have yet to find an interstate that to me is steep. Local roads....oh yeah!

I had a client with a 33% grade drive way for 100 yd, that was an interesting job. If you lost the brakes going down, you went thru the garage, kitchen, and 20' later you were in Lake Washington! 6-7% freeway grade, not a big deal, other than some rigs do not have the HP to hold the max speed limit. So you just go to the right, throw on flashers, and continue on your way! as long as you do not literally stall out, ie out of HP/torque and low enough gearing.....not a big deal. Blew up a TH400 or two or three due to the tall gears in that trans stalling it out more than once!

Marty

[noteven]

blt2ski wrote:

rowekmr wrote:
I think the steepest I have been on was 7% and it was in/near Chattanooga, TN IIRC. It was the only time my 00 Excursion downshift 2 gears and I still had to floor it to maintain 55 mph with trailer in tow.

Generally speaking, due to federal rules. Interstates will not be above 6%, with short bursts to 8%. Local city, county and state roads, especially forest service etc, you can see grades well above these amounts. Drive around the greater Seattle area in Puget Sound, road grade signs 15-18% are quite abundant. I know of one block on the north side of Queen Anne hill that is 24.5%. 11.5" of rise per 48" according to my tape and 48" level! Not a fun place to park while unloaded block for a wall I was building.

Then if you come out to Mt Hood, take the road up to Timberline, that is 10% for 10 miles or so. Even more fun coming down in a snow storm with a trailer in tow!

Marty

Marty - sounds like we should do a yoo toob channel called "slow lane twucks" on these roads - 🙂

[rowekmr]

I just drove the same route I think I took on my maiden voyage in my new (then) TT almost 7 years ago but this time in my wife's small car and almost can't believe that I wasn't scared then. The curves, inclines and declines had me challenged and concerned in a car. Maybe I am just getting more careful in my age.

blt2ski wrote:

rowekmr wrote:
I think the steepest I have been on was 7% and it was in/near Chattanooga, TN IIRC. It was the only time my 00 Excursion downshift 2 gears and I still had to floor it to maintain 55 mph with trailer in tow.

Generally speaking, due to federal rules. Interstates will not be above 6%, with short bursts to 8%. Local city, county and state roads, especially forest service etc, you can see grades well above these amounts. Drive around the greater Seattle area in Puget Sound, road grade signs 15-18% are quite abundant. I know of one block on the north side of Queen Anne hill that is 24.5%. 11.5" of rise per 48" according to my tape and 48" level! Not a fun place to park while unloaded block for a wall I was building.

Then if you come out to Mt Hood, take the road up to Timberline, that is 10% for 10 miles or so. Even more fun coming down in a snow storm with a trailer in tow!

Marty

[blt2ski]

rowekmr wrote:
I think the steepest I have been on was 7% and it was in/near Chattanooga, TN IIRC. It was the only time my 00 Excursion downshift 2 gears and I still had to floor it to maintain 55 mph with trailer in tow.

Generally speaking, due to federal rules. Interstates will not be above 6%, with short bursts to 8%. Local city, county and state roads, especially forest service etc, you can see grades well above these amounts. Drive around the greater Seattle area in Puget Sound, road grade signs 15-18% are quite abundant. I know of one block on the north side of Queen Anne hill that is 24.5%. 11.5" of rise per 48" according to my tape and 48" level! Not a fun place to park while unloaded block for a wall I was building.

Then if you come out to Mt Hood, take the road up to Timberline, that is 10% for 10 miles or so. Even more fun coming down in a snow storm with a trailer in tow!

Marty

[rowekmr]

I think the steepest I have been on was 7% and it was in/near Chattanooga, TN IIRC. It was the only time my 00 Excursion downshift 2 gears and I still had to floor it to maintain 55 mph with trailer in tow.

[blt2ski]

rowekmr wrote:
What is the grade of Stephens Pass/Highway 2?

ITs in the 4-6% range, depending upon the where etc. Problem is, in a couple of spots serious switch backs that make you slow way the heck down. Then you have to start up again. Overall, not a bad pass, been on worst ones. There is a local road with a switch back that is 18% for a mile or so, that one makes you squeeze the cheeks on the way up if loaded!

marty

[LowRyter]

4 tons is big load especially for a SUV- sounds pretty normal. Remember, if the tranny light comes on just pull over and idle and let it cool down. You'll be fine if you don't abuse it. Happened to my 6.0 2500 Silverado pulling my 5th wheel going up Monarch Pass. Bicyclists made me slow down and get off and on the gas. I let it cool off (all of about two minutes). The tranny fluid was fine.

[rowekmr]

What is the grade of Stephens Pass/Highway 2?

[Majja13]

When we go up to fish lake here in ut I have a couple real steep grades between a half mile and mile. I hit them with some extra speed and manually down shift usually hit top of the last steep part at like 4500 rpm and 35-40 mph in my old 2000 with about 6500 lbs. all sounds good rust remember like others have said try to always keep air flowing through the coolers.