Thinking out loud

[Vincent Vignola]

So a while ago I did a project for school on how to make a better towing rig than what GM already has, and I'm wondering one thing and it's hard to find: what's the crawling ratio for the 2-speed transfer case on the 2020 HDs? If anyone could help me out that would be fantastic! 

Edited July 21, 2020 by Vincent Vignola

[davester]

WTF does that have to do with towing?  Maybe define what you mean by "better towing rig".

 

Course, most likely this is a one and done poster...

[Vincent Vignola]

I wanted to keep it vague to protect my idea because I'm going to school for mechanical engineering and I have every intention of working at GM and giving them my overhaul plans for their trucks when I get there.

Edited July 21, 2020 by Vincent Vignola

[davester]

Really...your plans are so good you can't even define what "better towing rig" means to you...

[Vincent Vignola]

Better than Ford. Better efficiency, more power, more trailering control. That kind of stuff. However, if you dont wanna answer the question then dont man. I'm not here to argue my point. I'm here for answers.

Edited July 21, 2020 by Vincent Vignola

[newdude]

Hmmm.  With the 10 speed and 3.42 gearing, do you really need more?  35,000lbs max capacity is wayyyy more than anyone really needs, yet GM finally offers it.  You need a CDL to legally drive it, but they offer it.    

 

I guess I'm not seeing how one would "make a better tow rig" compared to what GM has now?  Get a bigger truck, that's about it really, class 6-8 truck really.

 

GM has upped the axles, they have trailer sway control via the Stabilitrak system, they squat less than Fords.  The 6.6 will gain power without a doubt I bet.  A dually solves your "trailer control".  

 

Using the low range?  The 10 speed eliminates any reason to even think about that.  1st gear is 4.54:1, the rear end is 3.42.  If GM wants more out of it, they just need to go back to 3.73 gears, which again, no need to even think about low range in the case.  

Edited July 21, 2020 by newdude

[BlancoSilverado]

I would say contact GM or a local dealer with a vin that you want to use and see if they can give you a ratio. 

 

I am also a ME/CE

[Donstar]

Playing with the idea that this is a legitimate thread, I will say your quest for a marketable, affordable, original idea is commendable and working with the design team at GM is an admirable goal.   Do your research.  Chances are high your "idea" is not original and there will be reasons for it not  already being marketed.  Don't be discouraged and be prepared to share fresh ideas and enthusiasm at an interview.  However, be clear on your intentions. Setting your sights on overhauling their trucks is fine but first you need to know what has gone into the current design. .  Most gearheads have plans swirling in their heads for the ultimate vehicle.  Watch the Velocity channel for awhile. I watch it regularly and my ultimate dream towing machine changes  nightly!  If only I had a few hundred k to spend on a truck!

[garagerog]

1 hour ago, newdude said:

 

 

Using the low range?  The 10 speed eliminates any reason to even think about that.  1st gear is 4.54:1, the rear end is 3.42.  If GM wants more out of it, they just need to go back to 3.73 gears, which again, no need to even think about low range in the case.  

Pffft, that ain't nothing to what GM used to offer. My son still has my old 84 K20 HD that was equipped with the SM465 manual transmission with the compound low or granny gear that had a 6:55:1  ratio, the transfer case was a NP208 with a 2:61 low range ratio and it had the 3:73:1 differential ratio. With the transmission in compound low and the transfer case in low range and engine at idle, you clocked forward progress with a calender, not a clock.

[KARNUT]

We had better towing ideas back when there was only 3 speed autos and non turbo 7.3s. Banks and gear vender was the answer. The auto manufacturers finally wised up. They been getting wiser ever since. There’re probably maxed out now.


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[newdude]

13 hours ago, garagerog said:

Pffft, that ain't nothing to what GM used to offer. My son still has my old 84 K20 HD that was equipped with the SM465 manual transmission with the compound low or granny gear that had a 6:55:1  ratio, the transfer case was a NP208 with a 2:61 low range ratio and it had the 3:73:1 differential ratio. With the transmission in compound low and the transfer case in low range and engine at idle, you clocked forward progress with a calender, not a clock.

 

That's great and all, but who uses low range to tow?  I can see moving something heavy no more than 10mph or something really oddball, or low range for pulling a boat out of the water at a boat ramp, but that's it.  

[KARNUT]

 
That's great and all, but who uses low range to tow?  I can see moving something heavy no more than 10mph or something really oddball, or low range for pulling a boat out of the water at a boat ramp, but that's it.  

People who work pipelines, utilities, general oil field work.


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[Bones454]

Volvo with series 60 motor.

[Vincent Vignola]

The main idea for me asking is for a gear splitting ratio. Tfl truck took a gmc 3500hd Denali crew cab up the ike with 30,000 lbs. They did the same with a similarly optioned f350. The ford had the powerstroke and a 10 speed auto, but it also had a 4.55 rear end iirc. The ford frankly performed much better than the gmc going up that hill, like 8 mins opposed to 11. The split speeds in a transfer case arent much more than a second transmission, and one can engage the low speed in 2wd if they wanted. I remember seeing 2lo on some transfer case designs, and this system wouldnt be much different than a semi trucks gear splitting box.

 

The idea is to make the rear gear ratio much longer to keep the efficiency up for low load cruising, and in tow/haul mode the transer case would kick down into low and give a much quicker effective gear ratio.

[MTU Alum]

You need to go to school and study thermodynamics.  You can have all the axle you want, running at higher rpms heats the oil, fuel, and coolant faster until you have to pull spark to protect the engine.