wow, im going to look into this. funny you mention this particular freeway, i drove it yesterday and was appauled at how bad my truck was shaking at 60mph! it absolutely beat the living crap out of me!

 

I dread going up that way! I have seen other trucks buck all over the place. I think alot of it has to do with being concrete.

 

I have driven this section of roadway many times back and forth from Reseda Blvd. to Vineyard in Ventura. In fact my favorite gas station is at Chesebro because it sells 104 Octane at the pump (for the Vette).

Anyway you can't expect GM to replace your suspension because of lateral movements (rocking) under the PCC slabs that make up the section of roadway that you travel. PCC has a longer pavement life then AC (Blacktop) so it is often used when there is funding to use it vs. AC. When there is additional funding to include it in a project. Sometimes with a new Highway Project there will be provisions for Rubberized AC which not only smooths the ride but also can serve as almost a mitigation for noise as it reduces the decibels. Also if the PCC panels get bad the road can be crack, seat, and overlayed with AC. But this is dependent on the need and purpose or justification for the State to qualify a project under the State's Operational Protection Program...there is no $$ in this program currently except for emergency projects.

But anyway the shifting in the panels is more associated with the structural section of the pavement which overtime can deteriorate because of geological issues (drainage, settling, soil conditions, rain, etc.) and continued use. This is what causes the panels to rock and then there is a noticeable difference between the joints....and with a stiff suspension such as with a truck or sports car...it is more noticeable. Normally it is worse in the lanes that large trucks (Semi's) that use the outside lanes so try and use the inside lanes and it might be easier for your ride.

You might get better results if you write letters to the Caltrans district maintenance office requesting a new project (vs. GM to replace your parts) or support your local sales tax measures that go towards road improvements since the State is broke and can't fix most roads that operate well but are not in the best drivable condition for somebody who owns a truck or sports car.

 

SR4 near me was the same before they polished it, its like they ground down the concrete to make it smooth. it made a huge difference but can still feel it at times. prolly just a matter of time till clatrans does that stretch too. a lot of other highways were done all over the bay area too.

 

I dread going up that way! I have seen other trucks buck all over the place. I think alot of it has to do with being concrete.

Yes...it is because of the frwy being concrete....but most all frwys are (concrete). The real culprit is the "expansion joints" between each 20ft cast concrete section. If the joint is not completely water tight (or nearly so), the ends of each concrete slab will rise as much as an inch over it's length, causing the well noted "expansion joint hop".

The only way to smooth out an old frwy that doesn't have the latest (and MUCH better) joint seals is by shaving. They use a HUGE carbide tipped drum/wheel that completely shaves off the high points at each joint connection...making each lane smooth once again. But the seals are not changed, and it will eventually rise again (but could take another 20 years).

The latest frwys don't have the same problem....or at least it's not nearly as noticable because of the MUCH improved joint seals in use today (water cannot get under the concrete slab ends causing them to eventually lift).

The scuttlebutt is that CalTrans has NO PLANS to shave the Venture "Grade-to-Bend" frwy section. They did shave the concrete frwy section between Ventura and La Conchita. It's a verrrry smooth/pleasant drive on that section.

 

The only real fix (I use that lightly) is replace the stock leafs w/ full Deaver Leafs, National, etc... w/ a shock you can valve (Fox, King, Bilstien 7100). This should minimize a lot of the expansion joint blues, but you will always feel it no matter what you do w/ a 1/2-3/4 ton trucks. The unsprung penalty weight w/ a 3/4 ton truck.

With my Dodge w/ 2.5 Kings & full Deaver Leaf Packs in the rear from Carli Suspension. It dramatically reduced the expansion joints. The minor to moderate ones my truck floats over them. W/ the more gnarly ones. I feel it, but reduced down.

 

The only real fix (I use that lightly) is replace the stock leafs w/ full Deaver Leafs, National, etc... w/ a shock you can valve (Fox, King, Bilstien 7100). This should minimize a lot of the expansion joint blues, but you will always feel it no matter what you do w/ a 1/2-3/4 ton trucks. The unsprung penalty weight w/ a 3/4 ton truck.

With my Dodge w/ 2.5 Kings & full Deaver Leaf Packs in the rear from Carli Suspension. It dramatically reduced the expansion joints. The minor to moderate ones my truck floats over them. W/ the more gnarly ones. I feel it, but reduced down.

I had 6" Deavers put in cause I was told it would eliminate the hop, If it would be worse than what it is now i would have thrown it off a cliff! I Drove the 5 fwy by Disneyland today and It was horrible! Is it just GM?

 

The previous bulletin I read stated there was no action taken on the 2500/3500's. That only the 1500 is going to get a revised mount... Is this supposedly for the 2500?
Also where does it state it will not be covered under warranty?

 

Has anyone else tried the fix from GM for the absolutely f@@ked up ride the 2500 has over freeway expansion joints?

The "Sulastic Suspension" mod to the rear mount of the axle springs doesn't even come close to helping.

I live in the Thousand Oaks SoCal area and travel the 101 Freeway through Camarillo quite often. It has got to be the MOST eye-tooth jarring ride in history....and that's only at 70mph. IF you even have the balls (left) at 80mph, more power to you! This is the KNOWN bad section of the 101 Frwy from the Conejo Grade, all the way to the Ventura Bend (about 8 miles or so).

GM's fix is to replace only the two rear BODY MOUNTS between the cab and chassis. It's NOT a warranty replacement...although it damn well should be. Luckily, it's only $200 (for parts only).

IMHO another good fix would be to replace all the rubber bushings in your Rear Springs, Hangers, LCA and UCA with polyurethane. The stock rubber bushings do not flex, they twist under tension, a Polyurethane bushing will flex and allow the suspension to work because it is not molded into a sleeve and then press fitted into the bushing eyes. You also might want to replace the body mount bushings with polyurethane as well. You may get a little more vibration on a rough road but you would have less body and frame twist because they do not allow the excessive flexing between the body and frame the way rubber does. I tossed every rubber bushing out of my truck and replaced it with Polyurethane. The truck feels much more firm, vehicle control is light years better and I hardly notice the road noise or the bumps compared with having the rubber bushings in there.

 

i know that part of freeway and drive it regularly. it sucks. i was going to do sulastics to help, but am glad i didnt because i guess it doesnt work.

 

Try driving it with a load of liquid. Just curious, what's the air pressure in your tires?

 

Rustie, That section of freeway has been like that since they widened it about 10 - 15 years ago. It has started to get worse the past few years. The number 3 lane is not as bad as the number 1 lane is, at least in the number 3 I can take my kidney belt off. They need to shave the surface to smooth it out, but I doubt that will happen until they have to replace broken sections or put a carpool lane in. I doubt replacing the mounts will fix the roughness of the road. It might dampen the bounce a little, but I doubt it will eliminate enough of it.

 

Chevy installed my cab mounts at no cost.They did help some,but they are far from a complete fix.On really bad roads,the truck still shakes alot.
I went through numerous tire balances(even a tire replacement at 1000 miles) trying to stop this problem.
My local tire guy is pretty sharp.He says the problem started on Chevy and Ford trucks when the manufacturers designed their frames to buckle in a head on collision to try and save lives which causes the "frame beaming".
I would try and get your dealer to install the cab mounts for free.They should.It at least helps the problem.

 

Am I the only one that doesn't have a problem with how it rides?


Tom

 

Am I the only one that doesn't have a problem with how it rides?


Tom

I don't have a problem at all. I would have bought a car if I wanted a car like ride.

 

Aprilwine:

.......You also might want to replace the body mount bushings with polyurethane as well.......

Just got the updated kit (they gave me a "discount" to $185...LOL!) They are indeed soft urethane cab bushings that replace the hard rubber OEM crap...as well as a different upper steel "donut" that mounts to the body (don't know what's different inside that unit).

Should have the dealer install them just because of principle....but don't trust the mechanics to do as good a job as I can....and they only require the removal of one simple bolt (and a slight raise of the cab).

 

i know that part of freeway and drive it regularly. it sucks. i was going to do sulastics to help, but am glad i didnt because i guess it doesnt work.

Don't get me wrong...the Sulastics did provide a small change, but nowhere near the full cure (or very nearly so) I was hoping for.

If this urethane body mount update AND Sulastics are installed (which is exactly what I'm doing), there should be a substantial improvement (I frikken hope!)

 

Am I the only one that doesn't have a problem with how it rides?

Well dood....you're obviously not driving along the Camarillo Corridor while out there in AZ.... ):h):h):h

 

ramman686:

Try driving it with a load of liquid. Just curious, what's the air pressure in your tires?

Yeah....my brother has the same exact 2008 HD, and he did put a bladder in the back. Only problem is that your acceleration and mileage suffer with a 600~800 pound water bag (especially acceleration). That's certainly an "option", but not one I want to utilize!!!

Did solve the problem though....that is until I trounced his A$$ on the onramp!!!

As soon as he got back home, he drained that Bag-O-Shieeet, folded it up and put it away.

My pressure is 70 front/60 rear (Terra Grapplers LT305/55/20). Don't want to reduce it below that level because of rapidly increased rolling resistance as the pressure drops. With the above pressure, the tire contact patches are fairly close with respect to front/rear (that engine is one damn heavy sucker ya know...)

Probably should have the front pressure closer to 80 to bring the contact patches to near exact matches....but the ride would probably suffer more.

 

I don't have a problem at all. I would have bought a car if I wanted a car like ride

.


Well, all I can say is that if you take your HD down the 101 frwy in Camarillo at 70 (MUCH worse if any faster), you can't possibly talk on the phone...and barely to one another! You're literally bouncing along at 5 to 8 cycles/second (Hz)...and your eye teeth are chattering!

It's that "frame beaming" causing all the problems, with respect to the wheelbase and the expansion joint positioning. It's totally f00ked up down here.....

 

The following is a "reprint", but it needed to be in this thread too....




OK....just finished the install of the General's "Frame Beaming" rear body mount units (only the rear 2 are changed out of 6 total). THIS was real damn easy...and if this works (still JUST AS speculative as the Sulastics though), I would try this waaaaay before I ever attempted another Sulastic install...even WITH being informed of all the pitfalls and special procedures.

All that was required to install the GMC rear body mounts is to remove the two long bolts holding those rear most mounts, along with the bottom rubber cushions and large formed steel washers. Then loosen (but do not completely remove) the forward 4 mounts (2 on each side...middle and front).

Once the rear most bolts are removed, simply position a floor jack with a 4x4 wood section about 14" ~18" long (or longer if lifted), and ON END. Just forward of these two rear body mounts is a body "hard point" (a large 1" diameter steel rivet head). Slowly raise the end of 4x4 right up against this rivet head as evenly and vertically as possible (NO angles here). The side of the 4x4 will slide up nicely against some sheet metal just inside this rivet (guiding it near perfectly). Also, make sure you don't crush any wires or lines you may have installed around this area (keep everything clear).

Slowly (with the other 4 mount bolts loosened about 1"), start raising the body at this rear corner. After you see the body move about 1" with respect to the bed, try pushing up on the existing steel "upper" body mount.

If you can get the mount to completely clear the frame mount hole...then simply slide it out to the rear...or jack up in 1/4" increments until loose enough to allow its removal (no more than 1/4" at a time now). Note that the mount has a "Double D" (2 flats) for orientation in the frame mount hole.

There will be a small, funnel shaped piece of plastic that is dropped inside the original upper steel mount's "through hole". Dump it out and re-insert it into the new "all steel" rear body mount in the same position. Not sure what it does, but it fits the new mount just as it did the old...and there is nothing structural, so re-use it (I think it's for bolt centering or some such thing).

Install the new washer, urethane "bump ring" (hard insert/flat side UP), and re-bolt it back in place, but do not tighten until the other side is completed.

Obviously, repeat this procedure for the remaining side (either side can be done first). Then same thing...add the new washer, urethane "bump ring", and re-bolt it back in place, fully tightening all 6 body mount bolts. You're DONE!!!

I'll let you know what this adds or doesn't to the Sulastic install. Certainly hoping for the best now that I have all the "cures" (except for Puffer's Frederico mods).

I'LL BE BACK.....

 

Let me know if it helps at all. Im dropping my truck off at the dealer in the morning to try this. I have high hopes, but Im sure will be let down.

 

Just FYI:

http://www.gmpartsdirect.com/

GM PART # 25791031
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $38.78
OUR PRICE: $23.80

GM PART # 25791032
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $38.78
OUR PRICE: $23.80

GM PART # 15854745
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $3.47
OUR PRICE: $2.13

 

Just FYI:

http://www.gmpartsdirect.com/

GM PART # 25791031
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $38.78
OUR PRICE: $23.80

GM PART # 25791032
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $38.78
OUR PRICE: $23.80

GM PART # 15854745
CATEGORY: All
PACK QTY: 1
CORE CHARGE: $0.00
GM LIST: $3.47
OUR PRICE: $2.13

Here is the list of costs on what's needed from page 2. Quantitys and descriptions below:

Upper Mount 25791031 Qty 2

Lower Mount 25791032 Qty 2

Washer 15854745 Qty 2 (if needed)

 

one cheap solution is tire pressure, 99% of people over inflate there tires, you can run 50-55 in the front and as low as 35 psi in the rear, a lt 245/75r16 tire will hold 2225 lbs per tire at 50 psi thats close to 4500 lbs for the front axel the rear at 35 psi will hold 1700 lbs per tire thats 3200 lbs for rear axel running empty the weights are cosher. studies have shown you will loose about .5-1 mpg but alot cheaper then all the parts required to acheve simaler results . just something to kick around .

 

well??

i know traffic is crappy in that area, but all day

 

Ok Doods....I’M BACK!!!

Just got back in from a double jaunt up and down that infamous Camarillo Corridor. The GM mounts fricken WORK!!! But first the low down.

So, if you were to assign this new HD's ride a number from 1 to 10, with 1 being where my HD was prior to Sulastics and GM's body mounts....and a Lexus or Caddy ride across the same convoluted strip of hwy as a 10....the new HD number after these two mods is a solid 5, or even as much as a 5.5.

Bear in mind that I would give my 4x4, coil sprung Yukon XL a 7, so that's a MAJOR IMPROVEMENT!!! Obviously, some "frame beaming" still exists, but it's been cut by MORE than half...and talking on the phone is no longer impossible. All this and at 80mph too! That was a near impossible speed to attain and still keep your eye teeth in place any time prior to these mods.

Ok....I would attribute about a solid 4 to the new GM mounts, and a 1 to 1.5 to the Sulastics. Yes, the Sulastics do not do all that was hoped, but if you want the best ride possible without even more extensive frame mods, BOTH will be necessary.

Just fully understand the difficulties involved when installing the Sulastics....or have someone who has already successfully installed them do the install (WITHOUT too much bed distortion). If you expect to install the Sulastics yourself, just be aware and prepped that you will need several jacks (3)....and it WILL REQUIRE some "under body bending".

That's it in a nutshell. Make your own decisions, but these two mods are certainly MUCH BETTER than carrying around 400 to 600 pounds of water in the back (ya think?)

Knock yourselves out.....

 

Glad it worked for ya.

The install of the sulastics must be harder on some years of trucks, mine was easy and quick.

 

Glad to hear they helped. Im dropping my truck off in an hour or so, I will try to post my thoughts tonight