Towing with a 305 V8?

[SirRobyn0]

I ain't the requested expert, but about the only thing I can think of is that there's a band that's applied in 2nd and 4th gear that can slip under heavy torque loads. They make a band with more surface area and a larger servo that applies more clamping force. It was the 3-4 clutches that would cook if your engine didn't have enough huevos to hold 4th gear. The fluid flows slower through the cooler in OD, but that'd probably be mitigated at least somewhat with a shorter final drive... and cooled more efficiently with an external cooler.

I've done the RPM calculations vs typical towing speed on the highway. 4.10's would allow me to be in a comfortable RPM speed in drive (I'd have to check my notes for specifics), for typical towing on the highway and still have a little bit more to go incase driving a little faster is a requirement (passing, traffic speed ect.). 4.56's would put right at the top of what I'd be comfortable with, and I'd probably be a the gas drinking stage. Going any faster would not be an option. Without using OD. Thanks.

Inattentive drivers, and the weezing underpowered engines of the day is the reason why they say not to tow in overdrive. As long as nothing slips in the trans, probably 80% of the heat created in the transmission comes from the torque converter. The transmission really doesnt care what gear it’s in, as long as it doesn’t slip or overheat.

The aftermarket does offer wide bands that span the entire width of the drum it’s wrapped around. There are also servos that provide more clamping force. There are 5 different servo sizes if I remember. TransGo includes different accumulator spring in their shift kits to tame the aggressive shifts of the larger servo.

I don’t think you can go wrong with 3.73 or 4.10. A big heavy truck hauling a trailer with an underpowered engine needs all the mechanical advantages it can get.

I'd have to check my paperwork as to whether or not a wide band was installed when the transmission was rebuilt last fall. I live in the hills, and where there aren't hills there are mountain passes. I currently have the 3.41 gears for me I don't think 3.73 would be enough. It's 4.10's or 4.56's to decide between.

I think I've already decided on the 4.10's just because it was kind of the gold standard in 3/4 ton and 1 tons, and I don't want to murder empty highway MPG. But until I finally get around to it, I like to explore thoughts and opinions. Thanks.

 

[Rusty Nail]

4.56 is for the quarter mile.
That's how to win drag races yo.

 

[CheemsK1500]

I've done the RPM calculations vs typical towing speed on the highway. 4.10's would allow me to be in a comfortable RPM speed in drive (I'd have to check my notes for specifics), for typical towing on the highway and still have a little bit more to go incase driving a little faster is a requirement (passing, traffic speed ect.). 4.56's would put right at the top of what I'd be comfortable with, and I'd probably be a the gas drinking stage. Going any faster would not be an option. Without using OD. Thanks.

I'd have to check my paperwork as to whether or not a wide band was installed when the transmission was rebuilt last fall. I live in the hills, and where there aren't hills there are mountain passes. I currently have the 3.41 gears for me I don't think 3.73 would be enough. It's 4.10's or 4.56's to decide between.

I think I've already decided on the 4.10's just because it was kind of the gold standard in 3/4 ton and 1 tons, and I don't want to murder empty highway MPG. But until I finally get around to it, I like to explore thoughts and opinions. Thanks.

I have a 2015 K2500 HD 6.0 gas/6L90 with with 4.10 gears. I get around 12-13 mpg empty. If a modern engine and transmission does this bad, I'd hate to see what a small block connected to a 4 speed would do. With that said, I can tow some heavy loads with ease but the 6-8 mpg makes me sad. I got this truck used, but if I had ordered it new, it would have 3.73s.

 

[CheemsK1500]

4.56 is for the quarter mile.
That's how to win drag races yo.

I run 4.56 in my '82 Scrambler and '93 F700. Both have 35 inch tires though.

 

[idahovette]

5.57s in my 56 wagon with 9.00x15 wrinkle walls

 

[JBswth]

Hello all, looking for some information on towing capacity.

I have an 85 C10, with a 305 V8, four barrel carb, automatic transmission, I think 5 speed.

The Truck belonged to my grandfather, He bought it new, and is completely stock with no mods.

The trailer I want to haul is my welding rig, a 12ft long cargo type trailer that weighs 2k pounds empty, and probably closer to 5k fully loaded. It is not a tall trailer so very little wind sail effect.

My question is will I be able to tow this with my truck? Is there any one out there who regularly hauls with a 305? everything I can find online seems to view it as a fairly weak motor not good for much. What do ya’ll think?

Any and all thoughts, opinions, or suggestions are greatly appreciated.

If your gearing is right, it will do fine, but if you have that rediculous 2:73 - 1 rear end, it will struggle. You should use 3:73 - 1 gearing.

Mike

 

[Ellie Niner]

Sorry for dropping off on you there... I used a hydraulic press to apply pressure, then took a hammer and tapped around the hydraulic ram to help persuade the metal back into place. I used sockets and various pieces of metal between the ram and the carburetor top, and drifts hacked out of a dowel and chunk of 2x4. I'm not familiar with working zinc castings... like how much pressure it would take before the crap would break, so I spent a lot of time bumping it a tiny bit at a go, and ended up still having just enough warp for it to seep a little... kept meaning to get back to the thing, and after a month or so (and daily driving the truck), the gasket swelled enough to finish sealing.

TCC lockup in 3rd gear is controlled by a vacuum operated switch that's screwed to the firewall, behind and slightly to the right of the brake booster (or left if you're standing in front looking into the engine compartment). It has one vacuum line going in and one wire coming out, and grounds the wire to apply the torque converter clutch. It's supplied with manifold vacuum from the back of the carburetor, then runs through a thermal switch and a delay valve. Just make sure you have vacuum to that switch when the engine is warm, and you can skip testing the vacuum modifier stuff for now.

 

[GTX63]

I have a 2015 K2500 HD 6.0 gas/6L90 with with 4.10 gears. I get around 12-13 mpg empty. If a modern engine and transmission does this bad, I'd hate to see what a small block connected to a 4 speed would do. With that said, I can tow some heavy loads with ease but the 6-8 mpg makes me sad. I got this truck used, but if I had ordered it new, it would have 3.73s.

I have the same set up and the same mileage empty. I love the 4.10 gear. Highway towing any trailer from utility to RV to heavy equipment is from 8 1/2 to 10, but then I'm probably "that guy", even in the right lane.

 

[JBswth]

Hello all, looking for some information on towing capacity.

I have an 85 C10, with a 305 V8, four barrel carb, automatic transmission, I think 5 speed.

The Truck belonged to my grandfather, He bought it new, and is completely stock with no mods.

The trailer I want to haul is my welding rig, a 12ft long cargo type trailer that weighs 2k pounds empty, and probably closer to 5k fully loaded. It is not a tall trailer so very little wind sail effect.

My question is will I be able to tow this with my truck? Is there any one out there who regularly hauls with a 305? everything I can find online seems to view it as a fairly weak motor not good for much. What do ya’ll think?

Any and all thoughts, opinions, or suggestions are greatly appreciated.

It can be done, but not with what I think the rear end is. There was no 5 speed automatics, so you have a 700R4, which was not very good in it's early years. I would put a 4:10 rear in it - your 4th gear is Overdrive, so your cruising ratio will be about 2:7 or 2:8 to one, plenty tall for the freeway, and deep enough for good hill-climbing and good acceleration. You will need an add-on transmission cooler if automatic, the big radiator, a fan shroud, and at least a 19 inch fan. If you can find one, a 20 inch is even better if you can find the right shroud for it. If you decide to replace that trans with a turbo 350 or 400, you will not have an overdrive ratio, so a 3:73 rear would be better so you can drive it better on the freeway.



James

 

[Velder]

Hello Again,

After learning so much from this thread, I am going to look around for a little newer work truck for right now. But I still want my C10 to be a capable backup truck that can tow my rig.

Definitely going to add the transmission cooler as suggested, and swap the rear gears to either a 3.73 or 4.10.

@ yes my mistake about the 5 speed, it is an automatic 4 speed.

Thank you for the advice.

Considering an engine swap, please take a look at this thread, and let me know your thoughts.

Thank you

 

[JBswth]

Hello Again,

After learning so much from this thread, I am going to look around for a little newer work truck for right now. But I still want my C10 to be a capable backup truck that can tow my rig.

Definitely going to add the transmission cooler as suggested, and swap the rear gears to either a 3.73 or 4.10.

@ yes my mistake about the 5 speed, it is an automatic 4 speed.

Thank you for the advice.

Considering an engine swap, please take a look at this thread, and let me know your thoughts.

Thank you

I would use the 305. Its good enough, it just needs gears.

 

[Rusty Nail]

It's just as well JB. At least the Blazer will find a good home with somebody that loves it. Dude has practically guaranteed himself to be stuck in the snow or mud later, but what can ya do? Ain't a Pokemon - you dont gotta catch em all.

xc_hide_links_from_guests_guests_error_hide_media

 

[Velder]

Hey @Rusty Nail, what do mean Dude has practically guaranteed himself to be stuck in the snow or mud?
would really appreciate your take on doing an engine swap, though I think I have already been talked out of it.
@JBswth thanks for the input, that is probably just what I am going to do, what gear ratio would you recommend?

 

[Grit dog]

Hey @Rusty Nail, what do mean Dude has practically guaranteed himself to be stuck in the snow or mud?
would really appreciate your take on doing an engine swap, though I think I have already been talked out of it.
@JBswth thanks for the input, that is probably just what I am going to do, what gear ratio would you recommend?

We don’t always understand what Rusty is saying….it’s ok.
Idk, not everyone who asks actually wants advice. But I recall you were wanting to make the ole truck a tow pig for a rig welding trailer.
It’s still no bueno even with an engine swap. And prolly what Rusty was referring to. Little ole 2wd truck, once it makes it’s painful journey down the road to the Jobsite (painful compared to anything GMT400 on up) all it’ll take is some loose, uneven or muddy ground and your the dude calling a guy with a 4x4 for a quick tug back to terra firma.
Engine swap? Sure. How fast you wanna go? I generally prioritize necessities over hobbies. Which in this case would be finding a reliable appropriate 4wd work truck to make a paycheck with and then decide how much you have leftover or want to spend on your grampas classic cruiser truck.

 

[SirRobyn0]

We don’t always understand what Rusty is saying….it’s ok.
Idk, not everyone who asks actually wants advice. But I recall you were wanting to make the ole truck a tow pig for a rig welding trailer.
It’s still no bueno even with an engine swap. And prolly what Rusty was referring to. Little ole 2wd truck, once it makes it’s painful journey down the road to the Jobsite (painful compared to anything GMT400 on up) all it’ll take is some loose, uneven or muddy ground and your the dude calling a guy with a 4x4 for a quick tug back to terra firma.
Engine swap? Sure. How fast you wanna go? I generally prioritize necessities over hobbies. Which in this case would be finding a reliable appropriate 4wd work truck to make a paycheck with and then decide how much you have leftover or want to spend on your grampas classic cruiser truck.

As a 2WD 84' C20 truck owner that tows occasionally I will admit this is a concern. I don't worry about it to much getting stuck on my farm most of my roads are good and the ones that aren't I just do the best I can and realize that I can get myself out of anything I get into.... On my place. Most of the places I get feed from the roads to the barns are good except the dude over the pass. His roads are all dirt and terrible. Easy to get stuck on those roads if it's been wet, let alone towing. That's my two cents on that bit. Just like anything else there are limitations.