Front End Rake, - Why Is It Even There In The First Place?

[mokeman3]

Hi, - brand new to the forum...

 

With my brand new truck: 2-week old '10 Silverado 4x4

 

My story begins here (before I get into my 2 questions). In October of 1995, I bought this 1996 F-150 4x4 with 4 miles on it:

 

 

It was a one-time stop, - I never been back to that dealer, and the trucks never been back to any dealer. 15 years later, and with 233,000 miles, the automatic tranny started acting up. Rear main was leaking, and last winter I was getting rod rap on cold starts. Truck's been worked hard, - countless yards of gravel, dirt, bark, plus I tow around a 18-foot Bayliner. Loved the truck, - got buffed out every year, and waxed at least 2X a year. Done all my own work on it (which was very little), brakes, hubs, U-joints, and a couple "slip yokes" (before I learned about lubeing the inner splines).

 

So I made the plunge, - got (what I believe was) a a good deal:

 

 

So now I'm wrangling on whether or not to level it, and if so, how much (1.5, or 2 inch), and which kit to use (RC under shock, or above shock). Like others have said, not sure how one would change the ride/handling characteristics since geometry wise, they both effectively do the same thing.

 

Premature wear wise? well, one poster there sorta hit on it, - CV joints will eventually need to be replaced anyhow, so how much more sooner they'd have to be replaced w/ a 1.5 or 2.0 inch leveling kit can't be by all that many miles.

 

So I have two questions (each not really related), and even possibly a third ...

 

#1)

I haven't seen the obvious question asked, or answered here...

And that is simply WHY did GM design this truck with the forward-leaning "rake" in it in the first place ??

 

#2) (unrelated)

My new '10 Silverarado has the 5.3L w/ the 6-speed automatic transmission. When the truck is cold (and even other times), I sometimes get a "clunk" in the rear end when I go to apply throttle. It acts like there is a lot of play in the driveline, or the engine/tranny controller isn't controlling the RPM's very well when letting off the gas, and then applying throttle again. Either that, or the thing is rocking the differential forward/backwards a bit enough for it to "bump" either the front tip, or the back tip of that short, bottom-most (thick) leaf in the leaf spring. Anyone else notice this with the 2010? I'm assuming (hoping) that is pretty much normal? i.e. a little early for the slip yoke to be binding up (which "sorta" shares similar symptoms).

 

#3) (totally unrelated to suspension, front or rear)

A/C.... Seems like a huge flaw in the BCM (Body Control Management as Dodge calls it) computer software that controls the "inside stuff". When you press the circular arrow button for "recirculate" interior air, it turns on the A/C compressor, but does NOT illuminate the A/C snowflake in the middle of the fan speed control knob. The Owners Manual is clear as mud on this. It say something to the effect that the recirculate function works in "all" modes or some such deceiving wording.

 

In the olden days, this used to be the "Max" A/C control that did BOTH, turn on the A/C compressor, *and* change the flapper position to recirculate cabin air.

 

On this rig, you can have A/C on (snowflake button lit), then press the 'recirculate' button (which then lights), then turn the A/C compressor snowflake button OFF (and the snowflake light goes out) but the compressor continues to run and cool the cabin down!

 

This is wrong in my view. You should be able to turn OFF the A/C compressor (when the cabin is cold enough), and be able to turn ON the recirculate cabin air button to preserve the already cold cabin air. Or if you want the fan to run withOUT sucking in outside air. At *minimal*, the recirculate button should also FORCE the A/C snowflake light to light (signifying that the A/C compressor really *is* running).

 

So what's the deal-O here? Is there a GM/Chevy hot-line I can call to talk to someone about this? (dealer is useless).

 

Thanks,

MM3

[Matt_]

#1)

I haven't seen the obvious question asked, or answered here...

And that is simply WHY did GM design this truck with the forward-leaning "rake" in it in the first place ??

 

 

It's so that the truck sits level when you're towing a trailer or have the bed filled.

 

If your truck is leveled when unloaded, the rear will sag when loaded and this will hinder steering/control/braking. Most people that level their trucks and tow often end up getting an airbag kit for the rear to prevent sag.

[mokeman3]

#1)

I haven't seen the obvious question asked, or answered here...

And that is simply WHY did GM design this truck with the forward-leaning "rake" in it in the first place ??

 

 

It's so that the truck sits level when you're towing a trailer or have the bed filled.

 

If your truck is leveled when unloaded, the rear will sag when loaded and this will hinder steering/control/braking. Most people that level their trucks and tow often end up getting an airbag kit for the rear to prevent sag.

 

 

Ah, - thanks (DUH...)

 

So I wonder how much the back sags when I hitch up the 17.5 foot Bayliner. (I didn't look last week when I had the boat out)

 

Or more importantly, I wonder how much the back will sag (if at all) once I get the new canopy that I bought plopped on next week. I did get a spray-in bedliner today (and had them do the back wheel wells), but when asked, they say that only adds about 30 Lbs.

 

If there the annoying rake still exists after the canopy, I'll re-evaluate a 1.5, or 2.0 inch level since 99.99% of the time I'll be driving around with just the canopy on, and no boat, or other additional weight, or have the bed filled.

 

MM3

 

MM3

[sic lsx]

for you to go spend some money on a level kit! Im getting mine soon!

[mokeman3]

Im getting mine soon!

Which one did you get, how high, and what was your decision/thought procession on those decisions ?

 

Thanks,

MM3

[sic lsx]

Rc 2"

[wescollins]

Gas mileage is a factor too in the rake. You'll notice at least a 1mpg loss when you level it. I'd recommend a 1.5" level kit. It'll still have a little rake but not bad. I had about a 2.5mpg loss after lifting mine 3", with the same tires. It also puts more weight on the front tires so it grips a little better, but of course you then lose traction on the back tires so gravel roads/snowy in 2wd is terrible with a big rake.

 

Is your truck in "auto" 4wd mode by any chance, if you have that option on your truck? I noticed a clunking sound a couple times taking off on a long trip this weekend, then realized about 200 miles down the road that I had it on, and I think that was what was different. It shouldn't hurt anything but you don't need it.

[tanked_darren]

Or more importantly, I wonder how much the back will sag (if at all) once I get the new canopy that I bought plopped on next week.

 

Not much, I got the same truck, canopies don't wiegh much. I have one on mine.

 

I think rake is for gas mileage.

[jro909]

its to compensate for weight on the ass end of the truck...if the truck is level and you put weight in the back the natural reaction is for the truck's front end to lift off the ground, which could lead to bad things

[AThomas7782]

#2) (unrelated)

My new '10 Silverarado has the 5.3L w/ the 6-speed automatic transmission. When the truck is cold (and even other times), I sometimes get a "clunk" in the rear end when I go to apply throttle. It acts like there is a lot of play in the driveline, or the engine/tranny controller isn't controlling the RPM's very well when letting off the gas, and then applying throttle again. Either that, or the thing is rocking the differential forward/backwards a bit enough for it to "bump" either the front tip, or the back tip of that short, bottom-most (thick) leaf in the leaf spring. Anyone else notice this with the 2010? I'm assuming (hoping) that is pretty much normal? i.e. a little early for the slip yoke to be binding up (which "sorta" shares similar symptoms).

That clunk sounds like your slip yoke. Very common problem on late model GM trucks. You can pack the splines with grease to improve it, but there doesn't seem to be a cure.

 

EDIT: Reading comprehension for the win...