Towing with a 2002 GMC Envoy

[Thomascine]

Originally Posted by JohnB

Hi Tommie,

What model year is the T1850?

Not sure yet. They only have the trailer listed as a 18ft Sunline. I am still on the fence about it so I have not contacted the seller. I think they removed the bathroom and maybe using it as a storage closet. Hard to tell from the pictures. I am not sure if I can live without a bathroom...LOL. I figured no point in contacting them if I can't tow it.

https://www.facebook.com/marketplace...8547884331561/

[JohnB]

Originally Posted by Thomascine

Not sure yet. They only have the trailer listed as a 18ft Sunline. I am still on the fence about it so I have not contacted the seller. I think they removed the bathroom and maybe using it as a storage closet. Hard to tell from the pictures. I am not sure if I can live without a bathroom...LOL. I figured no point in contacting them if I can't tow it.

https://www.facebook.com/marketplace...8547884331561/

I did some digging. I agree this does look like a T1850 like you found. I cannot tell the exact year, but it would 1 of 4 model years.

92 T1850 - 370# dry TW, 2,860# dry GVW on 5,000# GVWR
93 T1850 - 380# dry TW, 2,955# dry GVW on 7,000# GVWR
94 T1850 - 380# dry TW, 2,995# dry GVW on 7,000# GVWR
95 T1850 - 385# dry TW, 2,995# dry GVW on 5,000$ GVWR

Those were the only 4 years that floor plan shows up in the brochures. I'm not sure why they changed the GVWR from 5,000 to 7,000 and then back down to 5,000 but that is what the brochures are declaring.

That camper is larger and heavier than your current T1550. Between these 2 replies on this thread, we have a lot already figured out.

On tow capacity
http://www.sunlineclub.com/forums/f7...tml#post141675

And this one on rear axle loading
http://www.sunlineclub.com/forums/f7...tml#post141760

We used those estimates with your T1550 loaded full to 3,000# GVW with a 400# loaded TW, that would give you about 22% (2,306#) of extra reserve pulling capacity. Means the extra power your truck has for frontal area wind reduction and hills.

You are using your WD hitch and that helps keep your rear axle from being overloaded and running into the truck GVWR limit.

Basically putting it, the T1550 does work with your truck by the numbers as long as you keep your weights in check. You know how that feels towing the camper, acceleration and how the truck handles the camper suspension wise.

Going a T1850 jumps the weights. You go from a single axle camper to a 2 axle camper. The dry unloaded GVW weight of the T1850 starts (2,995#) starts at your loaded weight of the T1550 (~3,000#). The dry unloaded TW (tongue weight) of the T1850 (380#) starts close to your loaded TW on the T1550. (400#)

If we assume 1,000# of camping gear, LP gas, battery, spare tire etc on the T1850, that is going to put the camper at about 4,000# loaded. The loaded TW could be 450 to 500#. While that 1,000# of camping gear sounds high, it is not all camping gear that adds it. The battery, LP gas options etc are all part of that too. It is not very hard to hit that 1,000#. It feels like you are traveling light, so it is a good estimate to use.

That jump will put you at the limits of the ratings. I did not drill all the way into it yet to see how far over or not, but I can see you will be right there quickly. The truck may be able to handle it at the ratings, but you are going to have to watch the weight closely.

Gary (ggrvguy) had an 07 Trailblazer towing his T1990 Starray which he stated was 3,800#. The book value is 4,000 GVWR on his camper. This is smaller than the T1850 you are looking at but would be a good comparison if you "lightly" loaded the T1850. Gary has been around the block on campers and towing so I would value his opinion. See here http://www.sunlineclub.com/forums/f7...tml#post144287 A PM to him may help you see if his style camping and yours are close.

If you get the T1850, you will not be able to load it to the max 5,000# or worse the 7,000# GVWR of the camper. You will be very much over your trucks ratings.

If you really want a camper like this one, I am willing to run the calc's so you can see how you line up on the numbers. Just ask and glad to do it. On this one, it does look like they took the bathroom out to make for a bigger bed. I agree, no bathroom is hard to get along with once you have had one.

Hope this helps and good luck on you search.

John

[Thomascine]

Thanks JohnB! I think I will leave it alone. I am guessing that if I want to go a little bigger I will need to stay with a single axle if I don't want to change vehicles. Any good single axles that come up don't last long, at least the ones in good condition. You have to act fast if you want them. The biggest single axle is a 1700??? I will be working on the 1550 in the next month or so. Gotta get the tires replaced and I just bought supplies to change it over from single propane tank to dual. The regulator needs to be replaced so I figured this would be a good time. Who knows. Maybe once I have done all the work that is needed, I may have gotten adjusted to the 1550.

Thanks for the input! It is much appreciated.

Tommie

[JohnB]

Tommie,

You are very welcome. Glad to help anytime.

Originally Posted by Thomascine

I am guessing that if I want to go a little bigger I will need to stay with a single axle if I don't want to change vehicles. Any good single axles that come up don't last long, at least the ones in good condition. You have to act fast if you want them. The biggest single axle is a 1700???

Well, your right on the single axle part, as the single axle trailers normally top out at 3,600# GVWR or less due to the axle sizing. In the older Sunlines, it seems they limited them to the 3,000# GVWR. The T1660 seems to align with the last model in the 3,000# GVWR weight class that I have found. The T1700 is sort of on the edge. I have found some with tandem axles and then it jumps to a 4,000# GVWR.

I have not searched all the years brochures, but if it has 2 axles, then we have to hone in on the specs of it closers. A very light 2 axle one may just work.

John

[Thomascine]

I have a question for the experts since I am still fairly new to trailering.

Here is some background. I recently took a couple of trips that took be through or in the mountains. The first trip was to Hungry Mothers State Park. I could tell when I got to the mountains as my ears clogged up. The Envoy had an issue. At one point I could only go approximately 45 to 50 MPH and the RPMs went up to 3500 to 4000. The RPMs is usually around 2500 RPMs when I am towing the T1550 but never over 3000.

I am currently looking at a Chevy Avalanche. I need to know if the Avalanche would do me much better in situations like I described above. Would there be a benefit to having the Avalanche?

2002 GMC Envoy SLE, 4.2L I6, 4WD, 3.73 Axle Ratio, 5750 GVWR (5800 lbs maximum trailer weight)

2005 Chevrolet Avalanche Z66, 5.3L V8, 2WD, 3.42 Axle Ratio, 6800 GVWR (7300 lbs maximum trailer weight)

Thanks for your input.

[BenB]

It sounds like what you are describing is lack of power while towing in a hilly area. The Envoy and Avalanche both have similar engine power specs the Avalanche will have a some more peak torque. Envoy has 270HP/275TQ, Avalanche 295HP/330TQ. The transmission ratios are about identical but the advantage the Avalanche has is it will most likely have an external transmission cooler, unless you added one to the Envoy. The larger frame and longer wheelbase of the Avalanche will help handle a travel trailer better, but it sounds like your major complaint above is a power/trans issue. Were you towing for a long period of time or in an area with repeated large hills? Did the Envoy seem to tow normal when not in the hilly area or at the beginning of the trip when the engine and trans were cooler?

Unrelated to above, Avalanche's do make great camping vehicles and have some cool features. I may however be a little biased with that opinion since I have one[emoji16]

[Thomascine]

Thanks BenB.

Yes, I had an auxiliary transmission cooler added back in the Spring so I think I am good there. I try to pack light. It was the first time I towed that far, 5 hours one way, but I was only about half way. There was a dump truck in front of me that appeared to be having trouble. I tried to pass him and that is when I noticed the issue. It was brief (maybe a mile or two). I have been in hilly areas before, that is usually when the RPMs go up to 3000 (between 55 and 60 MPH). The rest of the trip was uneventful with RPMs from 2500 to 3000. It was just that one short patch. No issues on the drive back.

I test drove the Avalanche today. A different ride than the Envoy but if it is about the same as the Envoy then it may not be worth it. However, it does seem to have more room for my camping stuff and leave the front and back seats free.

Thanks again.

[BenB]

The good news is if it was an isolated event and not reoccurring you probably don't have a problem. Having the aux cooler added will help prevent overheating. GM did a good job with the 4.2L give almost all the torque at a very low rpm. Sure there is extra power and torque from the 5.3L in the Avalanche but I wouldn't say it's a "major" improvement. The 3.42 rear is going to multiply the power at a slower rate than your current 3.73 does so they are probably going to be similar in the power "feel" department.

The added cargo weight capacity could make things easier when loading gear as well as the actual extra space. We are able to put all of our gear in the truck bed and the back seats are empty which is nice. As mentioned before the larger frame and longer wheelbase will help with stability. The other "equipment" (brakes, suspension) that is built in the truck give it the larger tow rating, this will reduce how close you are to the max tow rating giving you more reserve rating. These are a few other things that could make it nice to upgrade if you wanted, but it seems your current setup is working properly.

One thing to check if you do seriously consider the Avalanche, some of them (I believe mostly offered on the 2WD models) is the factory Autoride air suspension. While this makes them ride nicely setting up a WD is difficult. I had an Expedition that had the factory air suspension and it wasn't so much fun and I didn't setup any sway control as I was only towing a flatbed trailer. It wouldn't be worth the hassle IMO, check to see if this Avalanche has that option so you aren't surprised if you buy.

[Thomascine]

I did a VIN check and this is what comes up for the suspension.

Thanks again for taking the time to help me figure this out.

[mainah]

Trans cooler is a must. In my former life I was a shop manager for a large transmission shop we would not warranty a transmission in a motorhome or a vehicle with a trailer hitch if it had no cooler. Your high revs in a sense is a good thing it is preventing "converter slip" the slip is what overheats transmission fluid. Most modern transmission have a lockup converter when it disconnects it feels like a lower gear it is not so now the converter can slip as you start to slow on a hill the trans will downshift to try and prevent this to a lower gear increasing the engine rpm because of the lower gear. When I drive an automatic pulling a load I manually shift it (comes from not owning an automatic) So higher rev are not a bad thing. I pull my T1700 with a Tacoma 4 Liter and a 6 speed manual trans going up through the notch in the White Mountains I'm down to 3 gear but I'm still passing loaded tractor trailers! If you are looking for more power nothing beats displacement.

[Thomascine]

Thanks Mainah.

I tow in 3rd gear instead of normal [D]rive. This is what the manual says so I do follow that. I am guessing it is because of what you described. It sounds like I should be okay for now. Which is fine by me. I don't really want a car payment right now. I mean I will if it will keep me camping but if it ain't broke...

Thanks a bunch!

[mainah]

Good, the Tacoma automatic has the same recommendations no overdrive. Because with a manual you are shifting all the time I very used to it so it does not bother me I never let my revs drop below 2,000 before downshifting, climbing hills 3,500 to as high as 4,000 before up shifting.