2006 H3 Driveline Noises

Hi, looking for insight on driveline noises. Yesterday, suddenly have scraping, grating, grinding noise in 1st or Reverse under acceleration and any gear under deceleration. No noise when after shift to 2nd, 3rd, 4th. No noise in N either rolling or parked. no noise in P. No noise when loaded in any gear and not moving. Trans fluid almost full, rusty brown, not clean red but not black. 2006 Adventure 175k miles. Half shafts solid, haven't checked front diff but doesn't seem that would be the case if silent in 2-4 gears. No notice at all.

Any insight or advice SUPER appreciated. High miles, lot's of freeway driving but mostly well cared for and we love the H3. Only second breakdown since new and it's never broken away from home. Magic.

It could be the transmission, but dont rule out other areas.

Check #20 & #29

http://twincharlotte.com/blog/30-common-4l60e-transmission-problems-repair-charlotte-nc/

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Check the front driveshaft first. Crawl under and pull it out...(4) 10mm at the t-case and (4) 7/16” at the front diff. Put the truck into 4Hi-lock mode and go for a drive.

If the noise is gone, you’ll know it’s NOT the transmission.

There is a cv-joint on the rear end of the front driveshaft and it is prone to failure. It’s a gold-colored cup with a rubber boot inside it. Look that thing over real good...the rubber often rips. If so it’s junk.

Report back.

Thanks much for the great advice. I'm traveling till Sunday but will drop the front drive shaft, check it out and report back.

took a while...

Removed front drive shaft. Nothing loose, no cracking at rubber sleeve/boot.

Drove in 4Hi locked, same noise, same time. 1st and reverse. If I go into neutral, coasting from 1st, the noise goes away. In reverse, if I go to N and coast, the noise stays essentially the same. In Neutral coasting backwards, noise is diminished if engine revs are increased (matching speeds internally or just increasing pumping?). Weird.

No slipping, shifts fine. Some minor off-throttle noise in higher gears but for the most part, once shift goes to 2nd and above, noise gone.

At least the drive shaft is out of the way for dropping the trans pan.

Thanks

175k on the original trans?

Yep... Soft foot.

That is quite a bit above the average life for the 4l60, doesn't mean it's the problem of course but certainly overdue for a rebuild. Rear u joints, slack in the transfer chain or the scrubber rolling around makes lots of fun noises.

I replaced mine at ~160K or thereabouts with a re-manufactured (not just rebuilt) unit since the old one was starting to slip. Good peace of mind to have if it is the transmission. Only ran me $1370 with a 3 year unlimited mile warranty including shipping both ways from Street Smart Transmission. If you pay to have a shop install it then the warranty also covers labor if it needs to be replaced again under warranty.

You have a bad low/reverse sprag! Check your pan, mine let go last August at 59k (I drive like a maniac). I had a massive shard that barely missed my pump rotor, but then I had 20+ rollers in the cracked sprag just waiting to wreak havoc. Thankfully I was VERY lucky and the rollers did not escape the sprag housing and grenade everything. Almost everything was rebuildable, minus the sprag. But I went a little crazy with a billet 1000hp unit.

I think many 4L60E transmissions have low/reverse sprags with weak housings that will crack, especially with excessive use of reverse or 1st in manual mode (especially with shift suppression added in a custom TCM tune). The sprag’s job is to hold the gear, and they just can’t seem to handle the work. This worries me because there is no upgrade part I am aware of for the low/reverse sprag. My new build has a brand new sprag, so I am hoping the latest parts are less prone to cracking, but my new trans may be at the mercy of the same issue (as would any 4L60E, stock or modified).

Good luck and congrats on making 175k with an original 4L60E, that is extremely impressive.