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

[Man With A Gun]

A friend of mine works for a Ford dealership here in Northwest Florida. He says all the time, they have trucks coming in that have to have the body separated from the chassis in order to fix the problem. $6 to $9000 every time. He says it is a continual ongoing thing.

Happened to the son of one of my Mom's friends.
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[Firebirdjones]

Wow, is that a Florida thing? We've never heard of that around here. This entire area in Arizona, New Mexico, Texas, are big on their diesels. A lot of ranchers, car enthusiasts, and especially large campers is a huge recreational past time here, so just about every other household has a diesel it seems to pull all their toys with.

I've had mine for 3 years now, criss crossed the country with it towing the trailer filling up in states between here and Ohio and have never had an issue with fuel (knock on wood )

[Man With A Gun]

I don't know how prevalent the issue is. He sent me a cell phone pic of their shop with three trucks that were in for the same thing.

I guess it can't be all that common with all the diesels out there. But if you work in a dealership repair shop you'd think they happen to everyone eventually. Anyway I went with the 6.0 with the little amount of towing I planned to do n
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[Man With A Gun]

Originally Posted by Man With A Gun

I don't know how prevalent the issue is. He sent me a cell phone pic of their shop with three trucks that were in for the same thing.

I guess it can't be all that common with all the diesels out there. But if you work in a dealership repair shop you might start to think they happen to everyone eventually. Anyway I went with the 6.0 with the little amount of towing I planned to do with it.
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[nsulacountry]

Originally Posted by Man With A Gun

I actually thought about getting a diesel truck when I was shopping for the 6.0 Silverado. I heard way too many horror stories about people putting in diesel fuel that had some water in it, which of course they didn't know until it's too late, and having several thousands of dollars in repair cost. The fact that I don't go more than a few times a year was enough to Pass on a diesel truck.
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Same here. I bought a 2013 GMC 2500 with the 6.0L due to horror stories of what repair cost are on modern diesels. Not to mention they cost more to service and maintain.

Water in fuel is a real issue on any diesel, on road or off.

As for the 6.0L winding up faster than a 7.4L big block is not apples to apples... 7.4L is a "low RPM" designed engine. Hence why it makes its torque under 3000 rpm. The 6.0L makes as much, if not more power than the 7.4L, but its designed to rev more. The 2011 up engines have VVT (variable valve timing) that makes the torque curve flatter.

With the 6 speed transmission, VVT, and 360hp@5400/380tq@4400 the 6.0L is a beast. A 6.0L at 4000 rpm is not damaging in any way, it is designed to operate this way to keep the engine in the peak torque. The engines of 20-30 years ago, not so much. 4000 rpm was approaching redline rpms.

Open to opinions... I have a 1979 C20 and a 2013 GMC 2500 HD. Each have their place.

CT

[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.
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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

[nekkidhillbilly]

Originally Posted by nsulacountry

Same here. I bought a 2013 GMC 2500 with the 6.0L due to horror stories of what repair cost are on modern diesels. Not to mention they cost more to service and maintain.

Water in fuel is a real issue on any diesel, on road or off.

As for the 6.0L winding up faster than a 7.4L big block is not apples to apples... 7.4L is a "low RPM" designed engine. Hence why it makes its torque under 3000 rpm. The 6.0L makes as much, if not more power than the 7.4L, but its designed to rev more. The 2011 up engines have VVT (variable valve timing) that makes the torque curve flatter.

With the 6 speed transmission, VVT, and 360hp@5400/380tq@4400 the 6.0L is a beast. A 6.0L at 4000 rpm is not damaging in any way, it is designed to operate this way to keep the engine in the peak torque. The engines of 20-30 years ago, not so much. 4000 rpm was approaching redline rpms.

Open to opinions... I have a 1979 C20 and a 2013 GMC 2500 HD. Each have their place.

CT

actually all 07 up hds have vvt and 6l90es. in 09 they changed from ly6 to l96s which means they are set up for flex fuel. my 6.0 will pull what ever no sweat. yes its going to downshift it has 2 overdrives. I came from a duramax to this truck and I wouldn't go back to that. it cost a fortune to keep running and in stock form it wasn't this big house puller like everyone acts like.