I have an 03 H2. It sat for 3 years while I was overseas. Upon return, I changed motor, transmission, radiator fluids with Lucas synthetics. The AC hi pressure switch failed, fixed it, then drove about 6,000 miles no probs. Truck is at 90,000 right now. I then bought a boat in Colorado, and drove it down to Florida. I hauled it on 3rd gear the whole time so it wouldn't hunt in and out of OD, and kept the speed to about 65mph, 3k revs. It started to sound like it had a powersteering noise. The truck has a Novi Paxton 1200 supercharger with liquid intercooler, 8.1 fuel injectors, ceramic headers, full exhaust, modified servos in the transmission. I had to pull a bunch of the supercharger tubing to get to the PS fluid, topped it up, but the noise did not go away. After that, I started thinking the supercharger bearings were going. The noise could be felt through the accelerator pedal on acceleration. It is my only car while I am waiting for my corvette to return from overseas. Sometimes this noise will go away and the truck sounds fine. Under WOT conditions it always sounds like **** (ever since the problem). A couple days ago, the noise went from sounding like the SC to sounding like something in the drive line. It sounded like rocks were grinding inside the transfer case or one of the differentials. The transmission has not slipped at all. I just don't know what to do, or where to start searching. Anyone have similar problems or noises? I have an appt at a Chevy dealership tomorrow and supposedly they can pull all the codes. Please reply with any ideas because I am at a loss. I am a pretty good mechanic, but these noises are baffling me. There are no forced induction shops in town to check the SC. Thanks, d'Art

 

BOTTOM LINE UP FRONT: My H2 is making a gravelly noise intermittently. I never take it out of 4HI, never goes off road. I am wondering if it could be a transfer case issue. The truck sat for three years, then I replenished motor, tranny and radiator fluids and drove it cross country for 6000 miles no probs. Then I hauled a boat for another 2,000 miles, and since then it developed a problem that at first I thought was the power steering (whine), then the blower (happened on acceleration) and finally the drive train (sounds like grinding).

MODS: Frame-off custo build from factory by Gorilla Motorsports in Tempe AZ. Novi Paxton 1200 SC, liquid intercooler, 8.1 injectors, custom ceramic coated headers, stainless exhaust. Porsche Arctic Silver custom paint job. Custom Leather interior. 5 DVDs, all Diamond Audio components with custom sub container. Custom build 3rd row seat. Integrated radar detector.

I hear that Chevy/Cadillac can pull codes in the TCCM that Joe Mechanic cannot. Is that true? Would HP tuners reveal all codes? How long does a blower last under routine operating conditions? Mine has 90,000 on the clock. Can the drivetrain be run in the air with all four wheels turning? I.e., any concerns about viscous coupling, etc?

Please reply with any help.

 

If you have a mechanical problem like the transfer case or supercharger bearings there will not be any codes for that. I would start by inspecting the transfer case, transmission and differential fluids for signs of metal. If the fluids all look good and clean then look at the belt driven accessories under the hood such as Alternator, idler and tensioner pulleys, supercharger bearings and so on. Good luck!

 

Thanks Calif Phil. Dealership responded it is the SC bearings. Getting it rebuilt by Paxton.

 

Super Charged H2s eat transmissions faster than a rastafarian on a breakfast muffin. I have a friend, he is on #3, and has that worked on again. The second tranny had some beefy aftermarket parts, the 3rd has all the bells and whistle HD Monster & Beast parts. His 1st T Case is still together.

Heavy truck w/4x4 driveline + lots of HP & TQ +heavy foot = something is gonna give. Trans is high on the list to be it.


Just sayin.

 

Thanks Doc, I'll knock on wood as so far I've not experienced any probs. I contacted the Custom shop that built the truck and they said as mine was their first build they now recommended I swap out the 1-2 and 2-3 servos to Corvette and Sonnax. I did so at 43,000 mi when I got the truck and have had no tranny probs over the last 47,000 miles. Of course we don't race is from every stoplight so, the 4L80E can provide good service life with a power adder if it is driven "normally." Cheers and thanks for the info re t-case life as well. FYI I had a 99 tahoe with 35" rubber that went through 4 4L60s in 200k mi with just a stock vortec... On this tranny I have used all synthetic fluid and changed it regularly

 

Sorry, Haven't been on this site in a bit.

Looks like it all worked out. I had my sc fail at about 90,000 miles also. same issues same solutions.

 

I've been told the tranny will last much longer if you just keep it serviced and always let it get warmed up before jumping in the throttle especially when towing. Glad you got it worked out.