Towing ability of 2004 Suburban 5.3L, 4.10, 4WD

[MartyW]

Can anyone give first hand knowledge of the towing abilities of a 2004 Suburban 4WD with 5.3L engine and 4.10 axles? It is 7200 MVGW and has Z82 hd towing rpo.

Thanks!

[blt2ski]

IIRC 7% is the steepest an interstate can be, and still get federal funding. ALtho for short sections, 8% is permited. Generally speaking, they seem to try to keep them to less than 6%.

I've never had issues with interstates.....local roads, like Queen Anne ave going north of FLorentia.....nice little 24% road to drop off or try to go up! Garfield on the east side has a block that is over 20% also. Those little short jaunts can kill you. OR the client that had a 33% grade driveway for 100 yds or so. You could get down it to the house, but not always BACK UP to the road. Of course, you could put a barge up to the dock, drive the rig on the barge, they could let you off at the nearest boat ramps some 4 miles away.........

Marty

[jerem0621]

I40 between Knoxville and Nashville has the steepest grade in Tennessee it's a 7% grade and it's pretty brutal.

Our 350 was in a 2000 Express 3500 Van and it's problem happened on a short but steep grade about 15 miles from the base of Monteagle close to Nick-A-Jack lake. I really liked driving that van.

Thanks!

Jeremiah

[BurbMan]

Doesn't look any worse than that grade on I-40 heading West out of Asheville, NC up into the Smokies....one of the few times the big block has needed 2nd gear with the 8500 lb trailer behind it. Might have to put that on the vacation list next time we head south!

[MartyW]

I added an edit note to my last post as Jeremiah was adding his post. Thanks Jeremiah for posting the video link.

[jerem0621]

The summit is the hardest on vehicles. What makes it particularly daunting is that it is peaking around a curve plus there is nearly a blind rest area exit. It's not too bad during a clear day but on a foggy night (common there) it can be treacherous especially when people realize they need the rest area at the last minute.

Iirc the grades are 4-6%

Thanks

Jeremiah

[MartyW]

Marty, I'm not sure of that bad grade at Monteagle. Jeremiah said he lives pretty close to there so maybe he'll know. There are yellow grade signs going down that grade but I can't remember what the grade is. For years I've shifted from OD down to 3rd to go down the hill watching rpm's but letting the engine help to throttle speed back. And going up, I've crossed that mountain several times pulling campers and I do just as you suggested. I think about that day a bunch, and I still think I didn't over rev. And that bad hill is at the summit going west-east, and it isn't very long, but it is very steep. There are somewhere around two miles of more gentle grade before hitting the monstor summit hill so the motor and trans are pretty hot by the time we get to the last/bad one.

And thanks for the info on flushing or replacing external lines/coolers. I'll have to make certain that happens.
MartyW

Edit: I just watched the video that Jeremiah pointed out and I don't think the video does justice to the steepness of that bad west-east summit hill. On the video the west-east crossing begins at 47 seconds into the video going up the sligher grades for a few miles, and then the bad/steep summit hill is reached at 1:34 and the top of the summit is reached at 2:00. It's that west-east summit hill where I lost my engine. Jeremiah is this where you lost yours or somewhere else on the mountain?

[blt2ski]

Jerimiah,

Not a bad pass. I am sure it is worst than it looks per say, but nothing I would go gaga over and not drive up it in a correctly loaded powered rig.

Marty

[jerem0621]

blt2ski wrote:
How big or bad is Monteagle pass? Can not be too much worst than some here in the NW I have done. ie 5-8% for 5-10 miles or so! Just shift down to a gear the motor does not get thrashed and pushed with the throttle at about 3/4, away you go at whatever speed that is.

ANyway, from some bad experience after one rebuild. I have found it best to flush or replace the rad and any external coolers during some rebuilds depending upon the what or why. Otherwise, the contaminants in the engine are more than likely in the rad/oil cooler lines and cause issues with a new motor at 2-3000 miles......not fun!

Marty

here is a video that gives some idea... its not nearly as long as some of the grades out west... but it makes up for it in adrenaline....

Video

[MartyW]

Jeremiah, I find myself thinking about that day a lot. I had the burb geared down locked in 2nd pulling the camper up that brutal west-east grade. I always keep an eye on the tach but that day I had to get around the big rigs with their flashers on and my eyes were off the tach for a few seconds. From the sound of the engine (that I was very used to after several years of owing it) I don't think I ever got over 4K rpm, but maybe that was enough. When we first acquired that burb there was a leak from the rear of the intake. When the engine blew years later my Chevy tech friend remembered that intake leak and he said that if any coolant got into the crankcase from that intake leak that the bearings could have been compromized by that leak and the final trip up hill could possibly have spun the bearing due to load plus damaged bearings. He said he had seen damaged bearings from coolant leaks before.

BurbMan, thanks for the explanation and info. My 5.7 with the hd towing pkg does send the oil through the radiator. I hadn't planned on replacing that. It has been flushed well by the Chevy dealer. I think we've already replaced the radiator but not positive at the moment. If not I guess radiator and external oil cooler will need to go (carringb did mention scope creep didn't he). I think I'll call the local dealer and ask about GM crate motor issues if they didn't install it.

Thanks to all,
MartyW

[blt2ski]

How big or bad is Monteagle pass? Can not be too much worst than some here in the NW I have done. ie 5-8% for 5-10 miles or so! Just shift down to a gear the motor does not get thrashed and pushed with the throttle at about 3/4, away you go at whatever speed that is.

ANyway, from some bad experience after one rebuild. I have found it best to flush or replace the rad and any external coolers during some rebuilds depending upon the what or why. Otherwise, the contaminants in the engine are more than likely in the rad/oil cooler lines and cause issues with a new motor at 2-3000 miles......not fun!

Marty

[BurbMan]

I didn't really have a choice on using Jasper....when I lost reverse in Murray, KY, the Good Sam Roadside assistance folks wanted to take it to a shop in Paducah, an hour away, called Mike's or Scotty's or something. Never heard of them, no website, no info. There used to be a transmission shop in Murray but the guy retired and it closed up, now there are none. I got the name of a shop in a nearby town, but had the tow truck driver tell me they were no good. I finally got the name of a local mechanic in Murray from a guy here on RV.net (who lives in Murray), and so happened he was a Jasper dealer.

The unit wasn't cheap but I got to thinking, if the guy in Paducah gives me a 1 or 2 year warranty and it quits a few states away, what good is the warranty? I would have rather the trans been rebuilt by a skilled rebuilder, it would have been cheaper, but since I was unable to find the right guy, Jasper was a good plan B. The more I think about it, it makes sense since we're all over the country in that truck.

Anyway, you are in a different situation, not being stuck away from home, and I would think that any GM dealer would provide warranty service on a GM crate motor if there was an issue. I'm not sure that I would pay more for a reman vs a crate motor either, but with the level of detail that remans are done at these days I'm not sure there's that much difference between new and reman anymore. Not trying to sell you on Jasper as a better option, just thought it was worth looking at.

Was doing some reading on the Jasper site today relative to installation, and it cautions that if the engine has an external oil cooler (my 8.1 sends engine oil through part of the radiator, not sure about the 5.7) the cooler must be replaced when the new engine is installed. Ironically I just put a new radiator in my burb because the plastic tank that houses the engine oil cooler cracked and was leaking coolant.

I also replaced all the brake and fuel lines this spring, heavy corrosion from too many years of beach camping when we lived on Long Island.

[jerem0621]

I had a thought about RPM's on the chevy 350 and the transmission shift logic. I wonder if the shift logic with the 4l60 and 80e's let the little small block over rev on a long pulls under the right conditions.

Thanks

[MartyW]

Thanks for the replies.

BenK, Thanks for the header info. From my limited exposure, and we're near Nashville, many headers I've seen seem to have gasket exhaust leak issues. Maybe cheap headers but I've always been a bit fearful of them for towing and getting them stinking hot climbing these Tn hills. Maybe I need to change my thinking if ceramic coating can change things.

Carringb, Thanks for the warning, but our '98 burb has been well maintained. A close friend at a local Chevy dealership has been watching it pretty closely for the past few years. I always ask him about rust and the body & frame are still very good. He did mention that the AC condenser had some rusty connections when he changed it a couple years ago, but this was probably from catching brine in the front, as it is our snow & bad weather vehicle. One of the reasons for deciding on the swap is because our '98 is a known quanty for 8+ years. The fuel pump, and both cats have already been replaced along with most sensors, ac compressor and ps pump/line. I do expect the ac lines from front to rear and brake lines to go one day but those aren't that big of a deal when just replacing all of them. I know folks who have done this.

Jeremiah, Misery loves company ha ha, and so you know for sure how brutal Monteagle is. My chevy tech friend has a newer truck with 6.0L engine and he won't go over Monteagle. He goes south into Alabama and then eastward when going to Florida or the east coast. He says that mountain is too rough on any engine. I think I've learned my lesson, well maybe... I think that with the new engine I'll probably run full synthetic oil from day one. I've been told by several folks that due to synthetic oil molecules being smaller than non-synthetic, that my original engine might have made it over that mountain that day if I had been running full synthetic. As I understand it only takes a dry spot for a split second to spin a bearing and maybe with the smaller synthetic molecules maybe that spot wouldn't have been totally dry? When mine spun I was going west to east, the brutal hill. The east to west grade seems a bit more liveable, but that west to east hill is a monster. I'm scratching my head also on why spend more on a rebuilt motor than a GM new crate motor as I've had new GM crate motors before with not a single problem. But on the Jasper side, the engine priced to us was with an RV cam that would be better for towing (I don't know if 4-bolt or not, but I'll find out). I see that Jasper has transmissions also, and if either an engine or transmission problem could be fixed under warranty when away from home with so many Jasper dealers nationwide, it is peaking my interest and ponderment...
MartyW

[jerem0621]

When we had a 350 main spin about 30 miles east of where you did (yup for real) we priced BRAND NEW crate 350's from GM, coupled with a local installer with nearly 20 years experience, we were at about 3300 installed before tax. It's really hard for me to justify a rebuilt motor that cost more than a factory new crate motor. IIRC the GM new crate motor was about $500 ish more than the GM rebuilt motor.

Good luck with your project. I am also of the opinion that now is the time to change all of the parts that are wearing due to age.

I live close to Monteagle so I do know how brutal these hills can be, especially on older equipment.

Thanks,

Jeremiah.