my wife asked me to turn the air on , 30 min later we had to roll the windows down to keep from sweating , my wife said u have had so much trouble with this truck u should trade it in . i asked the dealer to check it out ,they said the freon is within acceptable levels . what should i do ?its an 04 d/a gmc crew cab dually long bed with 25000 miles on it . so far they replaced the break booster and master cyclander, one rear break is at 25perecnt the other 3 are at 50 percent will they replace the breaks its supposed to have dynamic rear proportioning .the emergancy break dosent work they said they fixed it . the rear seal broke they ordered it over a month ago , the shocks i replaced them last week the stock tires where replaced 13000 miles ago . they didnt use much clear coat on the finish its all scratched up . and the rear end it really hot . dont know what to do . get rid of it or make them fix all the problems its a 50,000 truck still under warrenty . im being more patient with this truck than my wife is . its supposed to pull 23500 its not holding up its not even a year old . its dissapointing any suggestions ?

this is a known problem and there is a TSB on it... go to the forum just below this one and do a quick search. Find the TSB and take it in for it. There are a few little things that it could be and they are all covered under that TSB.

good luck

Yes there is a TSB on this GMCSID posted this just a little while ago under the TSB forum

.....its an 04 d/a gmc crew cab dually long bed with 25000 miles on it . so far they replaced the break booster and master cyclander, one rear break is at 25perecnt the other 3 are at 50 percent ...... the rear seal broke they ordered it over a month ago , ..... the stock tires where replaced 13000 miles ago . they didnt use much clear coat on the finish its all scratched up . and the rear end it really hot . dont know what to do . get rid of it or make them fix all the problems its a 50,000 truck still under warrenty ........ its supposed to pull 23500 its not holding up its not even a year old . its dissapointing any suggestions ?

I wonder what the True story is.

"..stock tires... replaced" @ 12,000 miles: (what is your tire pressures? )

"..its supposed to pull 23500...". Brakes = 25 and 50% @ 25,000 miles. Pumpkin running Hot. Rear seal leaking.

........the rear end has been running hot i checked the fliud, it was black and burnt and down a quart......

Did you ever change the rear end fluid?

Do you run Tune's, like Hypertech?

........ when i have a load in my dump trailor im at around 26000...

Just how much "Clear Coat" is needed to keep, kids, dogs, brush from Scratching the paint? How many times have you waxed the truck in 25,000 miles?

Please tell us the Rest of the Story.

Idahofox

i was around 26000 when i had 5 tons of gravel in it , i had to take all my tools off the truck and trailor now with 5 tons im at around 23000, most of the time im pulling the trailor under 20000 and it sets at job sights most of time ,ires on trailor are like new i keep 70 in them ,ive waxced the truck 6 times changed oil 4 times , going on my 4th fuel filter and allison spin on i keep my truck tires at 65 to 70 , im changing rear oil today for first time,ive had trucks for the last 20 yrs and ive never had a rear end problem or had to change oil in rear .

im using hypertech level 3 ,i have et guage since december , now i can tow in level 3 because just got the cat gutted ,i have air raid intake magna flow cat back 4 in stainless . i was towing on level 2 i had 20000 on truck going up a hill i could only go 35 to keep ets under 1200 now i can go over 45 up hill with same weight in level 3 since cat was gutted . im doing the best i can with this 50,000 truck i dont think its going to last ,not even a year old and has 25000 miles mostly highway without pulling a load i only have about 3000 pulling a load

the rear end runs hot with out pulling anything or hauling anything in it , when i bought truck ,the dealer has on invoice they put some kind of wax on it , now its all scrathched up and im wondering why they would put this wax on a new truck , looking back i think i know, my helper worked in a body shop he said clear coat helps keeps the finish ,scratch resistant, just washing truck puts scrathches on it . its easy to put a sctrathch on it . should it be that easy to scratch up the finish on a truck ?

i had a hd 3500 dump truck with a 454 and 4.10 rear with a 5 speed i hauled 6 ton in dump bed no troubles i added an extra leaf spring front and rear the truck took it easy i had 24000 in dump body twice hauling slabs of concrete a mile away truck took it easy i got rid of it at 40,000 bought this 3500 crew cab dually D/A and a 14000 dump trailor so i can be leagel gross combination 26000.a big difference between a 3500 and a hd 3500.i thought it would be a brute like the hd 3500 i owned that truck for 9 yrs. i had to replace breaks one time and tires 3 times ,im sarrry i got rid of it now and i traded my 2500 hd for this 3500 im sarry that i traded both for this . i learned an expensive lesson .

Ace,

You have several issues with your truck and they All can be resolved.

Lets take the Rear End first. There is no good excuse that the dealer has not replaced the Seal in this amount of time, you don't have their Attention, if you get my drift.

Black, Burnt gear lube is usless; Black, it's contaminated, Burnt, it's been Very Hot (the Chem Pack is gone). It must be replaced. Thats the owners responsibility not GM's.

Why is the rear end running Hot? What gets Hot first, Bearings or Gear Set? Low fluid level can contribute to this problem, usless lubricant (see above) Will contribute to this problem.

NOTE: "Oil", dino or synthetic, Never wears out, it gets heavy with contamination "Black"; uses up, loses the Chem Pack, sometime from heat, "Burnt". Either case its time to change lube.

NOTE: Low Lube Level. If there is only 2 or 3 inches of lube in the pumpkin, the Ring Gear will run through it and the Gear Set will recieve Some lube, enough to lube maybe, not enough to Cool, (dissipate the heat @ the Gear Set). If the lube is not high enough, the lube will not spiral outward on the axles to the Bearings, then the Bearings recieve No lube.

A HOT Bearing Will take out a Seal, you cook and harden it, given time. Your "..down a qt.." is very Telling. An inch or inch and a half low, no sweat, a quart low, trouble pending.

A Hot Bearing can affect Brake Pad wear. The Rotor dissipates the heat from a Braking event, if it can't Cool, by association to a Hot Bearing, the wear on one corner may differ from the other corners.

IMHO your Axle Seal, Hot running Rear End and Brake Pad wear situation have a common denominator; Low Fluid Level and contaminated lube, an Owner responsibility.

Were I in your situation, I would First try to determine the source of the excessive Heat. After an over night cool out, drive the vehicle, unloaded, just until the tranny shows some heat. Pull off in a safe place and get under the truck.

You should be able to hold the palm of your hand safely on any surface of the rear end. On the Cover, hold your hand on the Top and Bottom, watch for temperature difference.

The Top many be a Little cooler that the Bottom, (contact with the Lube).

Then check Left and Right, the Gear Set rides In a bearing set also. Then move to the spring perch area and feel the axle tube @ the Bearings. Asign the temps a grade from 0 to 10, 0 = Cold, 10 = Can't Hold my hand on it, and Write it down. Drive some more, then stop and check and Write it down. Do this until all temps are at normal, engine/tranny. You have developed a Temp Map, One point or more should Stand Out, if not, do this with a load.

Next I would pull the pumpkin cover, it has a reuseable gasket and your cost would be 4 qts of lube. Wipe the Gear Set clean of lube, ring and pinion (if you can see the pinion) (leave nothing inside that wasn't aready there, ie lint, pieces of paper towel etc.) Inspect the Gear Set for discoloration (heat distortion), spalding (lack of lube), chips on tooth edges/corner (physical damage), if you can, inspect the Gear Set Bearings for discoloration. The Gear Set will have some backlash, but you should Not be able to move anything out of alignment. Check it. Check that the Vent is clear, and the vent hose is not kinked or closed off, this is how the "Bogie Breathes". The seal is a wiping seal and not designed to contain an Oil Bath. A plugged vent can creat Positive Pressue in the unit and blown past the seals. Hopefully everything is OK. If you are not familiar with Gear Sets, a friend that is, would be helpfull.

Ref: 2003 Helm's manual vol 1, section 4, page 165. Lubricant Level ( 11.5 inch axle), "... 0 - 0.4 in below the fill plug opening". The only axle where the acceptable level is "0.6 - 1.6 inch" is the 8.6 inch axle, not ours. I know you don't have '03, I believe they are the same.

With the Gear Set checked out and it's OK, focus on the axle bearings. These units are Full Float'ers, ie, the outer axle bearings/seals are In the hub/rotor assembly, as apposed to being installed In the rear assembly Tube. These are healty Bearings and will take BooKoo abuse, but they die quickly without clean lubrication or improperly adjusted.

Is there wear patterns on the bearing boss area of the axle, (axle spinning inside the inner bearing race, bad deal, lots of heat)? Is the Bearing/inner race/outer race, discolored (heat), spalded (lube, lack of). Other terms used to discribe bearing damage: Brinelling, Indentations, Pitting, Misalignment, Frettage, Smears, Various Wear Patterns, Etching, Fatigue and on and on. If any of these conditions are found, the Bearing and both races must be replaced. If one bearing shows damage, there is a beter that 50/50 chance they are both damaged to some extent.

I believe the Brake Pad wear situation may be related to the heat problem. Fix the heat problem, replace All brake pads and start over, (replace the pads and save the rotors)!

I don't believe I said All that, what a mouth full!

Good luck, tomarrow is a New Day with New Horizons.

Idahofox

thank u for the imput, ill do all that ,if i need to replace the rear end , bearings and seals and break pads , could i go up to 4.10 gears ? do u think that would help ? would that work ? or even get a bigger axel. is it possable to install bigger beaks with ceramic pads ? would 85/ 145 oil work in pumpkin ?

thank u for the imput, ill do all that ,if i need to replace the rear end , bearings and seals and break pads , could i go up to 4.10 gears ? do u think that would help ? would that work ? or even get a bigger axel. is it possable to install bigger beaks with ceramic pads ? would 85/ 145 oil work in pumpkin ?

ACE,

Were I in your situation, after making the checks we spoke of earlier, and the bearings where questionable, my first focus would be bearings and seals, they can put you "Out of Service".

Your brakes are not critical Now, (25 - 50 %) if they are not contaminated, and can not be clean up. I would not change them until the Seal problems are corrected. Then change the pads as you can afford it. Maybe rear axle pads one month, front axle pads the next month. These brakes will do the job when maintained properly. Larger brakes are not indicated, IMHO.

The 3.73's are a good Balance for the DMAX. It is my understanding that 4.10's are available for this axle. That would be a very special application and very pricey.

If you truley need a larger rear end, you need a larger truck, I would not go there.

Mike L. states that these axles are set up so tight that 75W-90 is the best choice for lube. I bow to his expertiese.

Good luck, you have a lot of work to do.

Idahofox