2006 H3 Driveline Noises
 

Wondering if anyone has ideas about driveline noise on 2006 H3 Adventure 175k miles. Suddenly started today, fairly loud scraping and popping under acceleration in 1st gear, reverse and off throttle. Goes away with shift to 2nd, 3rd and drive (think). Zero noise coasting in neutral. No weird noises under load in 1st or reverse while stationary with brakes. No noise in neutral or park. Thought diff but no warning signs and doesn't make sense to be quiet in 2-4th gears. Transmission fluid maybe a tiny bit low and rusty brown instead of red but needs changing and not black.

Well that was helpful.... ;) . Crickets.

Could be any number of things. I'd start with u joints and go from there. Is it front/back/hubs/drive shafts/transfer case/etc?

Please keep in mind when you post at a forum.... my vehicle makes this, that, or the other noise... noises, loud, soft, hi, low all of that is completely subjective and we cannot hear any of it.

You want a wild guess? The ONLY time I have ever heard any H3 make a "popping" kind of noise was because the T Case chain was stretched out so far it could skip a tooth under heavy load.

Open up the front and rear diffs and take a look, you are at the miles a worn ring or pinion can miss a beat as well. Should be some gritty dirty gear lube when drained so take a look.

Guess #1. Front Diff Bushings
Guess #2. Right or Left CV
Guess #3. Tcase chain
Guess #4. Front Prop Shaft CV Joint
Guess #5. Could be anything else from the description above...:D

Thanks very much.

Been diggin in a bit more and appreciate everyone's help!
 

Been digging in. Took off front driveshaft (cv there looks ok, no looseness or leaks) . ran it in 4Hi locked and everything the same. So unless this is a very sophisticated H3 with speed sensitive electronic front diff, unloaded noise shouldn't change with gear if not attached right? Noise is grinding and popping, metallic sounding similar to caliper with no pads on rotor or broken rotor. Immediately goes away with shift to 2nd. Goes away with shift to N coasting. Present in R and stays when shifting to N while coasting in reverse. (Interestingly maybe is that seems to diminish while rolling backwards in N if I raise the engine revs). No codes. Maybe transfer case behaves differently under 1 and R than other ratios?

The Mystery In Summary - I'll offer a matchbox H3 Diecast to the correct prediction(s)

Grinding hard surface noise - Strong
1) 1st gear acceleration and deceleration
2) R gear acceleration and deceleration
3) Rolling backwards in Neutral

Grinding noise - Medium
1) Off throttle 4th Gear
2) Rolling backwards in Neutral but elevating engine RPM

Noise goes away
1) shift into 2nd through 4th acceleration
2) Shift into Neutral rolling forward from 1st (or any other forward gear)
3) Loading transmission against brakes stationery (in other words, no noise if wheels not moving - I don't know enough to know if this eliminates some moving parts of transmission)

Appreciate everyone's input. I'll probably take it into an independent guy I was referred to with my hands in the air but I'll report back to see who predicted the mystery solution. Thanks!

Might be your transfer case fork. Does changing 4H/4L make a difference?