Towing wobble

[steveoe]

Why would you want to tow in 4th? Especially if you're towing super-heavy?

Look at the construction of the transmission. Trace back its predecessors and you'll see it was originally a 3-speed and then evolved to a 4-speed when GM added overdrive by putting in a small planetary gearset. 3rd gear is a 1:1 drive ratio. 4th gear is a 0.69 drive ratio.

If you're towing in 3rd, the transmission has minimal stress; it's simply acting as a pass-through. The power is being transmitted through the strongest part of the transmission.

If you're towing in 4th, now you're transmitting all the power/torque through that small set of planetaries, AND they're having to multiply that torque as well because of the reduced drive ratio.

Personally, I'd rather send the power through the strongest part of a stock transmission than the weakest part of a built transmission.

But, then again, what do I know? I only have 325k miles on my weak, POS 4L60.

Makes sense I was towing in 4th but now reading some other forums about the 4l60 I will be putting that in 3rd from now on. When in third gear is the engine screaming going 60-65? Do u still have stock axles?

 

[Foggy]

That's why you'll have to slow down... The gearing and tire size determines your rpms if you are
in a 1:1 trans ratio - 3rd gear in a 4L60E. And if the trans is built correctly you "can" tow in 4th
to reduce your rpms.. Of course you have to be smart and downshift to 3rd on grades, etc... Just have to
finesse it and learn.
In the 6L80E there is NO 1:1 gear.... 4th gear is 1.15:1 and 5th & 6th are .85 and .67.
BUT, the 4-5-6 clutch packs are tiny... It's just a whole other animal.
In a 4L60e , yes 4th gear and it's components are the weakest and that's why you don't "load" the shit out of it in 4th
on a stock set up. But there are aftermarket builders and parts that can make it live if you're smart about how you drive.
On flat and downhill it's nice to shift up to 4th and give your engine a break in rpms.

 

[Fless]

For the 4L60 the problem is not just towing in 4th gear, it's the "hunting" or constant change of gears needed to keep speed. All the gear changes between 4th and 3rd burn up clutch packs.

 

[YukonRog]

For the 4L60 the problem is not just towing in 4th gear, it's the "hunting" or constant change of gears needed to keep speed. All the gear changes between 4th and 3rd burn up clutch packs.

So does driving in Auto 4WD! Constant hunting and Transfer Case engagement.

 

[steveoe]

Yeah I was watching some videos on the 6l80 and they swapped to a 4l80 for lots of horsepower they added to the engine. I live in Indiana so a lot of the roads are flat. This makes sense to just tow in 3rd now I appreciate the advice. So did the 14 bolt rear end ever come in 373s for the rear end that’s what I am gonna look at next.

 

[Geotrash]

Yeah I was watching some videos on the 6l80 and they swapped to a 4l80 for lots of horsepower they added to the engine. I live in Indiana so a lot of the roads are flat. This makes sense to just tow in 3rd now I appreciate the advice. So did the 14 bolt rear end ever come in 373s for the rear end that’s what I am gonna look at next.

Not that I know of.

 

[intheburbs]

Makes sense I was towing in 4th but now reading some other forums about the 4l60 I will be putting that in 3rd from now on. When in third gear is the engine screaming going 60-65? Do u still have stock axles?

The engine isn't "screaming," but yes, it's around 3100 RPM or so. My 01 is a worst case, because it has 4.10 axles.

Yes, still have stock axles.

The primary reason I upgraded to the 2500 is because I wanted the Godzilla 10.5" free floater rear axle.

The 2500 trucks aren't simply "beefed up" 1500s. Yes, they share the same body, but under the body is a completely different truck - virtually zero shared components - brakes, axles, suspension, engine, transmission, frame, radiators - all different (and better) in a 2500.

 

[Foggy]

Yeah I was watching some videos on the 6l80 and they swapped to a 4l80 for lots of horsepower they added to the engine. I live in Indiana so a lot of the roads are flat. This makes sense to just tow in 3rd now I appreciate the advice. So did the 14 bolt rear end ever come in 373s for the rear end that’s what I am gonna look at next.

Yes the 6L80E can have issues with high hp cars... My 6L80E I had "built" for me before
I put my supercharger on... Now the supercharger wasn't the only issue with giving extra HP...
It was the HP mixed in with a very heavy vehicle AND towing even more weight....
In say a camaro or corvette, caddilac ctsv a mildly modified 6L80/6L90 will hold 600-800 HP
just fine.... but those don't weigh 6500Lb and tow..
I have been thru many variations over the years with 700R4/4L60E and KNOW they will
hold power with the right mods.. My 700R4 (after the "right" build") has held together for
years in my car with over 700 HP.
I have also been thru 4L80E's .. yes, they are built well from the factory. But they are not
without their weak points.. Built mildly they can handle 800 HP and tow in heavy trucks ...
When built for all out racing , that # is way over 1000HP..

I liked my gear ratios in my chevy 1500 better with the 4L60E than my 4L80e..
but I couldn't make a 4L60e live with 700 HP AND towing my 9000lb camper...
With less HP it would have been just fine... But when not towing, it runs mid 11's @ 120mph

 

[steveoe]

I miss read some of the videos they were talking mostly about switching the 6l80 to the 4l80 not the 4l60. They were mostly single cab short bed trucks. I love those trucks like that. They did have a 4l60 that can hold 1000+ hps.

 

[steveoe]

So let me ask u guys this. If I have it in fourth and it stays in fourth is that bad for it too? Or just the switching from 4 to od the part that’s bad?