Locking Differental - Soft Sand

[BVOYLES]

2003 Chevy Duramax, 2500HD, Ext Cab, Short box, Locking differential.

When driving on a dirt road with pockets of soft sand, the rear end begins shuddering and banging violently whenever going through the soft sand. The shuddering becomes so violent it seems like something is going to break. Seems to happen when neither wheel has good traction. The only way to stop the shuddering is to back way off on the throttle and crawl through the sand at about 2 or 3 mph with very little throtle. Looking back at the tracks made in the sand by the rear tires shows deep cupping or scallop marks in the sand on both sides. Has anyone encountered this? Is this normal or is something wrong with my locking diff?

[GMC-2002-Dmax]

It sounds like normal wheel hop to me.

Stiff suspension, unloaded I assume, tires trying to bite and just a slippin and grabbin. :eek:

Mine does the same thing on certain dirt roads.

GMC ;)

[GMCTRUCK]

Mine does it also. Sand, loose gravel, deep snow etc. Not sure why, I've owned both older GMs and other brands with bigger spring packs and even blocks and not had this problem. Could possibly be due to the fact that the rear springs are long and soft for a cushy ride.

[mark45678]

I will 2nd the wheel hop! all that happens is the leafs rap up and release the stored energy and hop goes the rear axal! to stop it if you dont have a 4X4 good luck..... if you do turn on the 4 wheel drive ! Maybe weight over the rear end will help a little or lower your tire pressure to 15~20.... just dont let it bang a lot chances are it will confuse the tcm! I have been on a hill on a dirt road and had this happen.... shut the truck off restart it and have it in 4x4 for the next run

[conradv]

I too figured out that if I put my '03 in 4wd going up and around corners (gravel forest service roads) with extreme washboards, it makes the going A LOT easier.

There was one steep corner where it was hopping so bad, I wasn't even moving (in 2wd)...

[DieselDixon]

I get the same thing when in the sand, lowering the tire pressure helps a lot!

[BowTieDmax]

I agree with DieselDixon on the tire pressure. Depending how long you are going to play in the sand I would take the pressure down into the teens (psi). And this will take almost all of the hop away. smile.gif

[Joe P]

these trucks dont handle well in the sand,i was just fihing on the beach on tuesday,and my tires were at 20psi and iwas having alot of problems getting around. I drive this truck alot on the sand,seems like you have to drive slowly to get around.

[DieselDixon]

I drive this truck alot on the sand,seems like you have to drive slowly to get around.
As long as it makes it through is all that I care. I pull a 26' trailer at about 8500lbs through the sand half a dozen times a year and have not had a problem yet. We travel a good couple of miles round trip.

[DmaxMaverick]

A lot has to do with tire choice. My 285's are awesome in the Oceano Dunes sand. Very little chatter or hop unless they're aired up for the street. For a 7000 pounder, that is. I air them down to 18 front and 14 rear for the dunes, and I only have to drive about 1/4 mile on the road getting there. I think any less pressure than that and they'd need bead lockers.

With the stock pizza cutters, I can't imagine they would be much good in that stuff at any pressure (I never tried them in the sand). Just not enough sidewall and the footprint is too narrow. Don't expect them to perform well out of their ellement.

[DieselDixon]

I still have the pizza cutters on mine and they do pretty good at Pismo. Much rather have a wider foot print, but I am still trying to figure out what size tire will fit in the stock fender well. Maverick, you have those 285's on a stock truck?

Pizza cutters will be used one more time down there this weekend.

[DmaxMaverick]

Dixon

It's stock height. The torsion bars were cranked up a little. IIRC, it took about 4 turns and the tires don't rub. I removed the lower air dam as well (the GMC looks better without, I think). Judging by my license plate condition, I would have trashed it the last time I was at Pismo. Will probably be going back for the Thanksgiving holiday.

The smaller tires do OK for towing, but I won't go back to them. I like the extra load capacity, not to mention the looks and performance. The tires are mounted on 16 X 8 Centerline Comet III wheels.

[DieselDixon]

The tires are mounted on 16 X 8 Centerline Comet III wheels You have any pics?

Did you notice any differance in towing when you added the bigger tires?

[DmaxMaverick]

A little O/T here....

Not a lot of difference accellerating empty or towing. It is a little slower out of the hole, but once its moving, no difference. The mileage did increase about 1/2 mpg. It would probably be more with a non mud tire. Towing up long, steep grades (like Cuesta grade going over to Pismo...it'll do it at 65 mph with the trailer) seems better. It feels like the gearing is just right. It would effectively be a 3.42 with stock tires. My trailer is a high profile 5'er just shy of 12K. Anywho....

A few pics of the truck/wheels are HERE (http://community.webshots.com/album/88982014KqemjB)

There were a bunch of topics covering this stuff, but I couldn't find 'em. Musta got dumped.

[DieselDixon]

Yeah, I have followed most of them. I have talked myself into a 265 mud tire, just trying to figure out if I should go with the 285? My concerns are if they fit and if I have to turn up the torsion bars how is the ride effected and if I have to put a block on the rear end.

Thanks for the pics, truck looks real good.

[HD-Nate]

Originally posted by DmaxMaverick:

A few pics of the truck/wheels are HERE (http://community.webshots.com/album/88982014KqemjB)
DmaxMaveric,
NOT to Highjack the thread here but WOW I like those wheels. First aftermarket Ive seen that I like better than the factory! Didnt even think to look at Centerlines. Weld Wheels is based here KC and I have been looking at theirs but sure like the CL's better. Mind if I ask what you paid for them?

I know the wife will have the cable modem removed if I buy these :eek:

[lttlfeller]

DieselDixon,

You might consider 275x70x16s. They are real close the 265x75's but are a little wider and the overall height is slightly shorter. I went with 275x70's because I pull a 5W and was concerned about increasing the height of my pickup too much. The tire dealer set the 275x70 and 265x75 side by side and by looking the only difference I could tell was the 275 was slightly wider.

I went with the BFG AT T/A KO and have been very happy with them. unloaded ride is much better and they do great off-road in muddy/ rocky terrain. They are load range D but the load capacity is only 42 lbs less than my stock pizza cutters. Best I can tell my speedometer is off about 4% with the larger tires.

[ratlover]

I got 265's on mine since I didnt want any chance of rubbing since I will be sticking a plow up front. I have tons of room.....with no T bar crank. After I get a plow on her and see how much she drops I may really wish I went a bit bigger. Maybe the 255's? They are about the same hight as a 285 but a bit more narrow. I want narrower tires for the snow and such. Plus they are designed to work with the stock width wheel I believe.

I personally wouldnt worry about a 265 being too tall. heck they are what came stock on my Z71. :rolleyes: Still unsure of if I shoulda went bigger :confused:

sorry for the hijack

[Lonewolf867]

Those tires and wheels look SWEET! Good choice. I just might have to look that way for mine.

As far as what he described in the first thread. It sounded alot to me like the rear diff locking and unlocking. I have this happen at times when on a dirt/gravel/mud road. You really have to throttle down to get it to stop. I am not sure how much harm it could cause but that g80 diff locking and unlocking like that can feel like the whole back end is coming out. That is the biggest drawback to this diff. MY 2k z71 didn't do it as bad but it was still really annoying.

Mike

[a64pilot]

Mike,
From what you describe, it's not locking and unlocking, in fact it's not the differential at all, it's the wheels hopping. Short of installing traction bars or something like that the only other choiches are to increase traction, bigger tires / more agressive tread, lower air pressure or 4wd etc. or back out of it, in other words stop the wheels from spinning. BTW if you think your 2500 does it bad you ought to feel a dually with all of that unsprung weight when they start hopping ;)

[MadDuraMax]

Wow lot of discussions going on here,

If the rear end hops when it's not under power (foot off of gas) axle wrap is not the issue. Most likely is rear shocks and/or tire pressure. the quality of our OEM shocks (or lack there of) is well documented. Try the Rancho's or Belstien's.

At the Silver Lake dunes here in MI, the Park Patrol (DNR) mandates a Max tire pressure of 18psi! Air down those tires to 10 psi or so you'll see a big difference, I'll run 5/3psi on my MT Baja's without bead locks and have never had a problem. Depending on the sidewall construction of your particular tire, run as low as you can.

Also remember that the G80 only has about a 10 to 15 MPH window when it is actually locked and is UNLOCKED over 20MPH.

Hope this helps.

Mark

[ratlover]

Mine seems to act like its engauged at much higher speeds than that. Also acted that way in my 97 1/2 ton with a 10 bolt.

Most of the time the POS dosnt seem to engague at slower speed.....or is it that it just dosnt engague when I want it to :confused: :mad: :rolleyes:

[DmaxMaverick]

I can't really say what the torsion bar change did for the ride. I changed too many things all at once. It is much smoother than stock. It could be a lower needed tire pressure, the tires themselves, or getting the control arms a little further from the stops. The allison seemed to handle the change very well. The back space on the wheels are 4 5/8", which is what Centerline recommends for the 2500HD. Any less backspace and I think they would rub. I did have to tie back the E-brake cable and "adjust" the fender liners a little with a heat gun. It was easy and works really well. The overall bed height wasn't changed much. It came up about 1" from stock and no blocks are needed. I cranked up the torsion bars so the truck would be level with my trailer hooked up. I think it looks, rides, feels better now than stock.

The 285 are D rated (3305#), but are rated about 300# higher than the 245/E, and about 100# less than the 265/E. They handle towing really well with no diffenence I could tell compared to stock. I was originally concerned with sway, but it didn't happen.

The wheels were about $200 each. The center caps were $25 each. The wheels do not come with center caps. As I understood it, only the Extreme Duty line doesn't. If you want, you could use the old cup style caps and replace all the lug nuts (it was less expensive to just get the caps I wanted anyway). The center cap is held on with 2 bolts that thread into the wheel. The threaded holes are already there. If anyone does go this route, be sure to remove the set screw plugs in the wheels ASAP. It was about 2 weeks from the time I got the wheels to getting the caps (special order). The stainless set screws seized into the wheel and I had to drill and heli-coil 2 of them. Best thing would be to remove the plugs, anti-seize them, and reinstall. Be sure to also use anti-seize on the stainless cap bolts as well.

In regards to Weld wheels....
I think they look OK, but I have heard of too many quality issues when it comes to max loading. I had some on an older truck and after a couple tire changes, couldn't keep them balanced. It was the wheel, not the tire.

I am just about due for tires again. I like the Dueller M/T's, but I'm just not getting the wear out of them. I'll change them at about 37,000, which is about what the OEM's would go. Think I'll go with Revo's, or Dueller A/T's. They have a 50K warranty.

Back to the topic....
BVOYLES' problem sounds like hop, not locker problem. It should not hammer in and out. Wheel hop can be really violent and break things if allowed to continue. If it is the locker, it needs to be fixed 'cuz it's broke.

[MadDuraMax]

I know this has been posted before, but from Eaton:

Standard Equipment on Dual Wheel 3500 Series trucks.

[DieselDixon]

Well, THE PIZZA CUTTERS ARE HISTORY!!! Just got back from Pismo and got stuck twice, once with the trailer, back up off the hard pack after airing down, and the other time I was unloaded leaving camp after I just aired back up. Could have made it out the second time by airing down again but we were going on the roads for a while, never the less it should have not buried on me.

I already planned on going with the Centerlines, they have a line of wheels that are rated at 3200lbs. Now I just need to figure out the tires, I'm not getting stuck there again, NO WAY!

On the lines of the wheel hop, happened to me this weekend too, it was the second time I got stuck and was unloaded with 50lbs in the tires. As soon as you get on the gas the wheels hop, let off a bit and it stopped. Never once hopped on me when the tires were aired down, I put them at about 12lbs.

[Rockin]

I have the same problem with my Dakota that I plan to replace. I am curious if anyone has had luck with this specific problem (bouncing on washboard) with Bilsteen's or other quality shocks. It gets particularly scary when the washboard is a narrow icy road which is a common driving scenario for me.

[saywhat]

I put Bilstein shocks on the rear,they did not help in respect to the wheel hop.If I spin the tires the least little bit mine hops.I had a 2001 2500 regular duty truck with the G80 locker and never experianced wheel hop.If I use 4wd the hop is not a problem as I have went through roads under construction with deep loose sand with no problem,just keep moving.