intermittent grinding/clicking in reverse

C

chopper320

Member
Joined
Apr 23, 2014
Posts
25
Hey guys,

We have an 04 and 05 trailblazer and besides the common electrical issues and dirty throttle bodies, they have been pretty reliable for us.

Anyway, my wife has the 05 and recently it has started making a clicking or grinding sound when in reverse. It only happens occasionally and only last for a couple of seconds when it does. It almost sounds like gears or something of that nature slipping to me. It seems to happen more often after it has set for a few hours. It drives fine but it's a pretty bad sounding noise.

Any suggestions on what I should start checking? Thanks!
 
I hear "clicking" and I immediately think CV axle(s). Where is the noise coming from? The CV boots ever been inspected?
 
The sound is coming from the back end but I haven't pinpointed exactly where yet. The cv boots have not been inspected.
 
Is it 4wd? With or without G80? Mileage? Maintenance status on fluids?
 
Its 4WD. Sorry I don't know what G80 is but I just looked at how to check if I have it in the glovebox. I will check in the morning. The only fluid I know at this point is the oil is kept changed regularly. I will start with checking fluids and find out about G80 first things If I want to check the cv boots, should I just check for splits/holes and leaking grease around the outside?

Thanks for your help!
 
chopper320 said:
If I want to check the cv boots, should I just check for splits/holes and leaking grease around the outside?
Click to expand...
Yes. Tell tale sign is grease slung toward the cabin, typically all over the wheelwell. But a close visual inspection is best.
 
133K? You had it since day 1 or did you buy it used? If you bought it used, at what mileage?

I'm just trying to get an idea when if ever, the transfer case fluid was changed or even had the level checked. The requirement is every 50K, and folks who let it go to 100K sometimes need a new transfer case, the damage can be severe. Even if 4WD modes are never used. Even if you find bad CV shafts making the noise, you need to jump on that TC. And the differentials were due at 100K. Lots of stuff makes noise when it runs dry.
 
Oh, man. Wish you had discovered the forums back then so we could have given you the traditional advice. Buy a used vehicle without maintenance records - change EVERY fluid as soon as you bring it home, and negotiate a lower price because of the possible latent damage. Insist on checking fluid levels and quality during the pre-purchase inspection. Especially on this platform with the known transfer case issues. Good luck when you look into the TC and the diffs. Would be nice if it was something relatively cheap like the CVs.
 
Thanks. What exactly should I be looking for when I check them to know if there is any damage done? I actually have 2 trailblazers and they have about the same mileage on them. The other trialblazer is an 04 and I bought it with around 60k miles on it and I know that the fluids have never been changed.

It is not showing any issues beyond electrical things like hvac vents and instrument gauges but now that I'm hearing about this I'm going to look both vehicles over and change the fluids.
 
Measure the amount of fluid that comes out, so you will know if it's been low. Make sure to always remove the FILL plug first to make sure you can refill it after you take the drain plug out. Look in the fluid that drains out for metal flakes, dust, or fragments. Compare its color ot the color of new fluid. Differential oil, for some reason having to do with being sealed up, STINKS very distinctively. You'll never forget it, if you go into this as a differential oil change virgin.
 
ok thanks so much for your help. To answer the earlier question I do not see G80 on the truck.

It looks like the transfer case fluid is only available from the dealer so I'm stuck waiting until Monday for that.

I've tried to find a thread with good instructions on changing the front and rear differential fluids but I'm having trouble. Does anyone have a good link?

Does this sound like the best plan to start with?
Change differential fluids
Check cv boots
then monday change transfer case fluid?
I will check amounts of fluid to see how much has been lost when I change and look for any debris.
 
Always check member MAY03LT's videos on Youtube for how-to instructions. Or the Article section here, although Google hasn't caught up with the great reindexing of 2014.

Rear Diff
https://www.youtube.com/watch?v=5XP7v3ezv-0

Front Diff
https://www.youtube.com/watch?v=qST91kDjTIE

Transfer Case:
https://www.youtube.com/watch?v=qcjiWgNWD3Q
 
Ok. I checked the boots. They are dry and I don't see any cracks or splits

I changed the front and rear differential fluid and I was able to locate some Autotrak II at an oreilly's so I changed the transfer case fluid. It was hard to determine how much I drained into the pans but all 3 oils were black. I did not see any debris anywhere though.

Its still making that grinding noise in reverse. Any suggestions on what I should check next or is it beyond home repair at this point? Thanks again!
 
ok. Thanks for all of your help. At least I found out about those maintenance items and got them done. I'm going to do our other trailblazer next weekend.

I'll probably take this one into the dealership this week to see if they can track down the problem. I'll post back here whenever I find something out.

This is a great forum. I can't believe all of the help that's available here!
 
There should be PLENTY of competent independent GM mechanics in your area. I have one i always take mine to if I'm in over my head.

Just sayin', unless you have a special relationship with a special dealership, they've been known to abuse people, sometimes being so stealthy you think you haven't been fleeced.
 
The_Roadie said:
There should be PLENTY of competent independent GM mechanics in your area. I have one i always take mine to if I'm in over my head.

Just sayin', unless you have a special relationship with a special dealership, they've been known to abuse people, sometimes being so stealthy you think you haven't been fleeced.
Click to expand...
Good point. How do you go about finding an independent GM mechanic though? I was actually thinking along the lines of "I don't know any mechanics so if I took it to the dealership, they are a big enough business that I should be able to trust them"
Sounds like the wrong thought process though lol
 
Google. Yelp. Newspaper. Word of mouth - ask friends or co-workers. Then CALL them. If you haven't checked out the DEALER using Yelp and Google for good reviews, you're just a sheep waiting to be fleeced.

In your location, there should be PLENTY of dealer-trained mechanics who left because they couldn't stand the BS and they're good. There could also be incompetent ones who couldn't stand the demand for productivity and got fired. The trick is to use available resources to distinguish the two kinds. With the Internet, we're not in a vacuum anymore.

How do you find a dentist.? Or a dog groomer? Or a new barber? Not by random chance......follow that process and thinking. Aren't parents teaching this sort of thing anymore?
 
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