Towing Capacity: my Uncle's 1986 GMC Camper Special 1T Dually

[Man With A Gun]

Longbed
454 gas
3 speed automatic (pretty sure it's a TH350)
4.10 rear diff
2 WD
Dual rear wheels

Any ideas how much I can tow with this beast?

[bilfman]

Won't tow anything worth a darn, just sell it to me and save yourself the headache

[mongocanfly]

Looks like a repaint got the door sticker ..it got mine to,,but I think its around 9500-10000 gvwr..i cant remember..they will pull more weight but I'm sure that's a saftey factor in there..mine is tagged for 30000 gross lbs but I wouldn't want to do it. It depends more on the condition of the truck than anything..I've seen some I'd be scared to haul a sack of taters in.but I got a buddy that regularly pulls a 12000 lb skidsteer and on ocassion pulled a d3 behind his he just has to be careful what he does

[Keith Seymore]

Originally Posted by mongocanfly

Looks like a repaint got the door sticker ..it got mine to,,but I think its around 9500-10000 gvwr..i cant remember..they will pull more weight but I'm sure that's a saftey factor in there..mine is tagged for 30000 gross lbs but I wouldn't want to do it. It depends more on the condition of the truck than anything..I've seen some I'd be scared to haul a sack of taters in.but I got a buddy that regularly pulls a 12000 lb skidsteer and on ocassion pulled a d3 behind his he just has to be careful what he does

Towing is different than gvwr. GVWR is gross vehicle weight (total truck and cargo with no trailer). Towing is GCW (gross combined weight); trailer weight would be gcw less the truck (including cargo, fuel and passengers).

Originally Posted by Man with a Gun

Longbed
454 gas
3 speed automatic (pretty sure it's a TH350)
4.10 rear diff
2 WD
Dual rear wheels

Any ideas how much I can tow with this beast?

I happen to have the '78 chart handy; it should be pretty much the same for your '86.

Factory rating is 15,000 lbs combined, with the 4.10 gears.

K

[Man With A Gun]

Originally Posted by mongocanfly

Looks like a repaint got the door sticker ..it got mine to,,but I think its around 9500-10000 gvwr..i cant remember..they will pull more weight but I'm sure that's a saftey factor in there..mine is tagged for 30000 gross lbs but I wouldn't want to do it. It depends more on the condition of the truck than anything..I've seen some I'd be scared to haul a sack of taters in.but I got a buddy that regularly pulls a 12000 lb skidsteer and on ocassion pulled a d3 behind his he just has to be careful what he does

What's a d3?

[jjmorrse]

Mel Gibson pulled a house, so they are pretty robust. GMs are like that. A blue Monte Carlo towed an entire church. That was the 70s Monte, they downsized in 81, so it could only tow a small chapel, probably.

[Man With A Gun]

It's definitely the TH400, not the TH350 transmission. And Bilfman I think I'll keep it. Thanks for the offer. Haha

And it's no longer my Uncle's truck at this point - it's mine for $4500. Thing drives like it was new.

60,800 original miles. We know the owner history up to when it was purchased new. Uncle is the third owner, I'm fourth. Car fax says it's perfect.

I've got a new headliner, door panels with all the fixins, and a carpet set that came in on Friday. Keeping the dash because it only has two small cracks. I'd like to get an original radio and maybe put some good aftermarket speakers behind the seat. Window is fogged up around the bottom but FL insurance will replace it if I get full coverage.

[Firebirdjones]

They tow pretty good. I have basically the same truck with the exception mine is a single rear wheel. 79 1 ton 454/400 with 3.73's. I've pulled my 28 foot enclosed trailer several times, including a trip across country and it does a decent job. With load distribution bars it actually rides and handles pretty well. With a car and gear loaded inside it's every bit of 10,000 lbs. (trailer empty is 5,000)

With your 4.10's you might be limited with cruise speed. Unless you want to really spin that 454 pretty hard you'll be going 55ish at about 2800 so I wouldn't want to be in a hurry.
I ran mine across country with 3.73's cruising around 26-2800 which was 60-65 mph and it did fine, and even knocked down 10 mpg on fillups. Mine even climbed the mountain grades around here without too much difficulty, and maintained a decent speed. If you want to tow with a gas engine, these trucks are as good as it gets, and was really the best their was for that time period (diesels had not really evolved yet in the late 70's to what I consider better) However I never intended to pull that kind of weight with mine when I bought it over 20 years ago and honestly don't like to subject it to that either. With that in mind and doing even more towing nowadays than I ever planned, I broke down and bought a duramax.

Today the diesels are where it's at if you really want something to tow. I bought a duramax a few years ago and can tell you first hand pulling the same trailer on the same roads, it's night and day difference. I can pass cars pulling that 10k lbs trailer up the mountains and that thing doesn't even break a sweat. If you plan to do a lot of towing, more than 3-4 times a year, it's the way to go. If I were still only towing once a year and sometimes not even that, then I'd still be using the ole' 79, it does the job fine.

[Man With A Gun]

Originally Posted by Firebirdjones

They tow pretty good. I have basically the same truck with the exception mine is a single rear wheel. 79 1 ton 454/400 with 3.73's. I've pulled my 28 foot enclosed trailer several times, including a trip across country and it does a decent job. With load distribution bars it actually rides and handles pretty well. With a car and gear loaded inside it's every bit of 10,000 lbs. (trailer empty is 5,000)

With your 4.10's you might be limited with cruise speed. Unless you want to really spin that 454 pretty hard you'll be going 55ish at about 2800 so I wouldn't want to be in a hurry.
I ran mine across country with 3.73's cruising around 26-2800 which was 60-65 mph and it did fine, and even knocked down 10 mpg on fillups. Mine even climbed the mountain grades around here without too much difficulty, and maintained a decent speed. If you want to tow with a gas engine, these trucks are as good as it gets, and was really the best their was for that time period (diesels had not really evolved yet in the late 70's to what I consider better) However I never intended to pull that kind of weight with mine when I bought it over 20 years ago and honestly don't like to subject it to that either. With that in mind and doing even more towing nowadays than I ever planned, I broke down and bought a duramax.

Today the diesels are where it's at if you really want something to tow. I bought a duramax a few years ago and can tell you first hand pulling the same trailer on the same roads, it's night and day difference. I can pass cars pulling that 10k lbs trailer up the mountains and that thing doesn't even break a sweat. If you plan to do a lot of towing, more than 3-4 times a year, it's the way to go. If I were still only towing once a year and sometimes not even that, then I'd still be using the ole' 79, it does the job fine.

Thanks for all the info. I'm thinking about reinstalling the fifth wheel hitch and towing the same fifth wheel camper he towed with this truck- I bought that from him two years ago. He said he towed all over the mountains with this truck and never had a single bit of trouble. He loved camping in the mountains. It's about all the camping he ever did.

I'm currently towing the nearly 12,000 camper with my 07 Silverado 2500 HD with the 6.0, 3.73 rear end and six speed transmission. It's right at the max end of the towing capacity if not just a tad over.

Would this be a better choice of towing truck than the 07 Silverado? I've got the fifth wheel hitch, bed rails and supposedly all the nuts and bolts that came with it. Holes are still there in the bed too.

I've always avoided the mountains since it does tend to downshift on long grades on Interstates that aren't even in mountainous areas with the 07 Chevy. I'd like to be able to go camping in the mountains.

[Firebirdjones]

Originally Posted by Man With A Gun

I'm currently towing the nearly 12,000 camper with my 07 Silverado 2500 HD with the 6.0, 3.73 rear end and six speed transmission. It's right at the max end of the towing capacity if not just a tad over.

Would this be a better choice of towing truck than the 07 Silverado?

I can tell you my father has a brand new 2015 with the 6.0, 6 speed trans, and 4.10's in it. My old 79 454 pulls circles around it. We pull the same trailers and any time we hit a grade I literally walk off and leave him unless he mashes the throttle and forces the trans to downshift. If he doesn't do that he falls behind and then has to play catch up on the flat. The 6.0 just doesn't have the grunt of a big block. They do claim a decent torque rating from that engine but it doesn't make it until 4,000 rpms or there about, where the 454 makes all it's grunt off idle and below 3,000 rpm, much better suited for pulling without needing to scream the engine.

So if you tow a lot with that 6.0, I think you are going to find a world of difference on grunt when you hook the same trailer behind that 454.

After experiencing both, and even having my own 6.0 truck for a while, I'll take my 79 454 any day of the week for towing. The only thing out there better is a diesel, which is why I bought one and got rid of the 6.0.

[Man With A Gun]

Thanks, Keith. That's exactly what I was looking for.

[Man With A Gun]

I probably tow about 4-5 times per year, maybe 6.

I've currently got three trucks. A 77 Chevy K20 Camper Special, this '86 CS Dually and the '07 Silverado. The 77 is just a classic vehicle as far as I'm concerned. It's cherry and not used for work.

So I might sell the 07 and tow with the 86 from what you're telling me.

[Firebirdjones]

Tow with both and see what you think. You may like one better than the other and have a completely different opinion of what I found.

With the 4.10's, you may not like the cruise speed while towing if you want to keep from working the engine too hard.
I find my 79 with it's 3.73's suits me about perfect. I can cruise at 65 @ 2800 so it's not working too hard, and that's about as fast as I care to go when pulling 10,000 lbs. behind me. With 4.10's you'll be spinning about 3200 to do that. Again not horrible but you probably won't like the gas mileage doing that.
Mine would get exactly 10 mpg average on every tank pulling across country 3200 miles. Worst was 9.8 and best was 10.3.

Your 6.0 truck may or may not do that well on gas while towing. I can tell you mine didn't. It wasn't any better than my 454 on gas, again I feel that's simply because that 6.0 had to really work and the trans had to hunt for gears. It pulled fine, but I had to really work it hard. The only advantage the 6.0 had was that overdrive trans with multiple gears. As long as I was on completely flat ground the engine could loaf along at a much lower rpm than what my 79 454 spins. But it's rarely ever flat for very long and soon that 6.0 is hunting for gears and screaming. While my 454/400 turbo just keeps buzzing along @ 2800, no fuss.

Even with all that said, since you only tow 5-6 times a year, you might not mind using the 454. That's pretty much been my story for more than 20 years and I was just fine using it. Last couple years I started towing 11 to 12 times a year up and down the mountains, so my towing doubled in frequency. The 6.0 won't cut it around here with the mountains. That pushed me to buy a diesel.

[Man With A Gun]

Thanks, I'll definitely tow with both before I decide.

[jjmorrse]

A TH350 pan is relatively square with a corner cut off. A TH400 is more complicated shape. One generally expects to see a TH400 in a HD truck in those years.

Towing, like driving, is an experience. Once it is established that a rig has the capacity, try it out. Some people don't like setups that run through gears more to stay in torque peak. Other people could care less. Some vehicles just feel more solid. My old 71 camaro felt super fast. It had a deep tone, and it chirped the tires in third gear. It vibrated more as it accelerated. Objectively, it was as fast as a modern stock mid-grade import sedan. If it is more fun or reassuring to use the old truck, that seems a perfectly good reason to me. Type of trailer makes a difference too. A gooseneck feels a lot different and more stable than a bumper pull. For long trips, fuel mileage might be a factor as well. Maybe just take a trip in all the candidates, and see what fits.

[Firebirdjones]

Originally Posted by jjmorrse

Some people don't like setups that run through gears more to stay in torque peak. Other people could care less.

I see that a lot around here. It amazes me that I still see a lot of people using small gas engines to pull car trailers, horse trailers etc... Boy they scream to climb the grades around here. I never liked spinning that little 6.0 at 4000-4500 rpms for 5 minutes at a time climbing grades.
Talk about some serious engine wear if you tow a lot!!! And it would drink the gas like that too. I guess that doesn't bother some people, but I quickly found out that's not what I wanted. Just hard to beat old school big blocks with a simple 400 turbo behind it when you want to pull a load. Even the later year 454 and 496's were nice with the 4L80 behind it. They towed nice.

A shame GM killed the BBC, it really doesn't give people a suitable lineup of gas engines to choose from for towing purposes anymore in my opinion.

[slotard]

Originally Posted by jjmorrse

A TH350 pan is relatively square with a corner cut off. A TH400 is more complicated shape. One generally expects to see a TH400 in a HD truck in those years.

Towing, like driving, is an experience. Once it is established that a rig has the capacity, try it out. Some people don't like setups that run through gears more to stay in torque peak. Other people could care less. Some vehicles just feel more solid. My old 71 camaro felt super fast. It had a deep tone, and it chirped the tires in third gear. It vibrated more as it accelerated. Objectively, it was as fast as a modern stock mid-grade import sedan. If it is more fun or reassuring to use the old truck, that seems a perfectly good reason to me. Type of trailer makes a difference too. A gooseneck feels a lot different and more stable than a bumper pull. For long trips, fuel mileage might be a factor as well. Maybe just take a trip in all the candidates, and see what fits.

I agree that I'd expect a TH400 but for some reason my C20 Camper Special has a TH350 (and had one from the factory). 350/350/4.10 means it screams on the freeway.

Originally Posted by Firebirdjones

I see that a lot around here. It amazes me that I still see a lot of people using small gas engines to pull car trailers, horse trailers etc... Boy they scream to climb the grades around here. I never liked spinning that little 6.0 at 4000-4500 rpms for 5 minutes at a time climbing grades.
Talk about some serious engine wear if you tow a lot!!! And it would drink the gas like that too. I guess that doesn't bother some people, but I quickly found out that's not what I wanted. Just hard to beat old school big blocks with a simple 400 turbo behind it when you want to pull a load. Even the later year 454 and 496's were nice with the 4L80 behind it. They towed nice.

A shame GM killed the BBC, it really doesn't give people a suitable lineup of gas engines to choose from for towing purposes anymore in my opinion.

I suspect they killed the BBC thanks to CAFE requirements, but don't know for sure. Diesels have some significant advantages too.

Originally Posted by Man With A Gun

Wow. If my high school trig is right (class of 85) that's about 12.7° on average. I'd be in third gear in the 6.0 at best. Probably doing what, maybe 35mph? And it may need second at least once. Scary to think about.
Posted via Mobile Device

I seriously question a 6-8 mile 22% grade, if there is one I'd like to know where. The Grapevine on I5 north of LA is a 7% grade I think (or is it 6%?) and considered fairly steep.

I think a 4L80E or some other OD option would make a huge difference on a bigblock with 4.10s, and AFAIK it's very similar to the TH400 other than OD. There are manual options that would work well too.

[Keith Seymore]

We use Towne Pass (Death Valley) and Baker Grade (Baker CA) to do our Powertrain calibration and HVAC development work, due to their length, change in elevation and ambient temps.

K

[ironroad9c1]

Originally Posted by slotard

i agree that i'd expect a th400 but for some reason my c20 camper special has a th350 (and had one from the factory). 350/350/4.10 means it screams on the freeway. I suspect they killed the bbc thanks to cafe requirements, but don't know for sure. Diesels have some significant advantages too. I seriously question a 6-8 mile 22% grade, if there is one i'd like to know where. The grapevine on i5 north of la is a 7% grade i think (or is it 6%?) and considered fairly steep.

I think a 4l80e or some other od option would make a huge difference on a bigblock with 4.10s, and afaik it's very similar to the th400 other than od. There are manual options that would work well too.

4l80 would only help unloaded or lightly loaded , you never pull a load in OD so you would be in 3rd 1 to 1 anyway same as a th350 or TH400

[nsulacountry]

Originally Posted by ironroad9c1

4l80 would only help unloaded or lightly loaded , you never pull a load in OD so you would be in 3rd 1 to 1 anyway same as a th350 or TH400

+1 on OD. 4L80e is essentially from an engineering standpoint a TH400, that is electronically controlled with OD.

The TH400 is technically named by GM as the 3L80.

4L80/4L85 ratios (1, 2, 3, and R same as TH400) TH 350 has different ratios.

1st 2.48 (2.52 TH350)
2nd 1.48 (1.52 TH350)
3rd 1.00
4th 0.75 (only 4L80)
Rev 2.07

The 6L90 in my 2500 HD will tow a light load on flat ground in 5th. Heavy loads and up hills towing 4th.

6L80/6L90 ratios

1st 4.027
2nd 2.364
3rd 1.532
4th 1.152
5th 0.852
6th 0.667
Rev 3.064

Personally in an 86, 1 ton... TH400 all the way!

CT

[Man With A Gun]

A couple of times, I had it slip down into third gear on a very long grade on the interstate. Usually it's in fourth or fifth. It didn't really bother me. It does make me think twice about going into the mountains with the 07 Silverado with the 6 L gas engine.

I'll probably put the fifth wheel hitch back in the 86, and have both to choose from, depending on where I want to go.
Posted via Mobile Device

[Firebirdjones]

Yep, a lot of that depends on the terrain you live in. I would think Florida would be pretty flat from what I remember last time I was there.
Out here we have grades that are 6-8 miles long and climb from near sea level to 7,000 feet, so that little 6.0 is in passing gear a LOOOONG time, lol. Trying to maintain at least 55 mph so you don't get run over is pretty tough when you only have 364 cubes under the hood and twice the weight of the truck hooked to the back bumper. It can be done but boy that poor thing is wheezing for quite a while.
Even the mild grades in Ohio on I-75 I would run away from my fathers new 6.0 with my 79.

[Man With A Gun]

Originally Posted by Firebirdjones

Yep, a lot of that depends on the terrain you live in. I would think Florida would be pretty flat from what I remember last time I was there.
Out here we have grades that are 6-8 miles long and climb from near sea level to 7,000 feet, so that little 6.0 is in passing gear a LOOOONG time, lol. Trying to maintain at least 55 mph so you don't get run over is pretty tough when you only have 364 cubes under the hood and twice the weight of the truck hooked to the back bumper. It can be done but boy that poor thing is wheezing for quite a while.
Even the mild grades in Ohio on I-75 I would run away from my fathers new 6.0 with my 79.

Wow. If my high school trig is right (class of 85) that's about 12.7° on average. I'd be in third gear in the 6.0 at best. Probably doing what, maybe 35mph? And it may need second at least once. Scary to think about.
Posted via Mobile Device

[Man With A Gun]

22% grade. Yikes.
Posted via Mobile Device

[Firebirdjones]

That's the worst of the worst out here, even small cars have problems climbing it, lol. That's why I won't own any kind of car unless it at least has some sort of V8 in it. Semi's are usually in the right lane pulling maybe 20-30 mph with a load. Speed limit is 65 up the hill but people fly up it 75+ if they can. Speed limit is 75 out here otherwise. Closing rate is quick when you run up on a semi, lots of fatalities along that stretch of road. I hate driving it actually. But I certainly won't pull a trailer up it unless I have one hell of a truck. I don't want to be a road hazard. It's not uncommon to see cars, trucks and semi's pulled to the side with the hood up. I see ALOT of U-Haul box trucks like that in the summer time.
The 79 does it easily with a 16' flat bed trailer and a 4,000 lbs car on it and I can maintain the speed limit without downshifting. When I pull the 28 foot enclosed it's more of a strain of course but I can still maintain 50-55 mph and the truck stays in 3rd gear (high gear). For a 36 year old big block truck it's respectable, but I still don't really like putting the truck through that. So when I started towing more and more I got the d-max. That thing is hilarious. I can pull that same 28 foot enclosed fully loaded, truck never downshifts and it will go as fast as I care to go, I've hit 75 going up that hill by accident when I pulled out to pass some slow cars and mashed on the throttle a bit. I absolutely love it.
But when it comes to gas power engines, I think you'll like that 86