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New 2008 Avy owner! What MAINTENANCE should I do?

AirspeedX

New Member
Joined
Jul 27, 2021
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2
Just picked up a 2008 Avalanche LT with 220k kms on it (Canada) or 137k miles.

What should I do maintenance wise?

It's in good shape overall. Front end seems tight.

I'm worried about the AFM. Might look into the Range AFM disabler if I can find it in Canada.

Here's my list:

Fix rear door handle (popping out)
Change diff fluids and t-case
New AC Delco Iridium plugs
Transmission flush? Might leave this alone.
Oil pickup oring? It has good pressure but the lifters do sounds a little clacky on startup. Should I do the oil pump while I'm at it?
Drivers side valve cover?
U-joints (fiance says she hears grumbling when letting off the gas at highway speeds).

Also when I roll the drivers side window up, the motor seems to be engaged for a few seconds longer than it should and clicks a few times. Any ideas?

Happy to be on here. Did tons of reading but thought I'd make a thread.
 
🍿

I picked up an '08 w/133k on the clock. Drove it ~100 miles to its new home. The TPMS light was on and shortly after purchase the CEL came on. I also noticed steering wheel shake at 70-75mp and that the front end is generally sloppy. Feels like a bag of jello with rocks in it when I encounter significant bumps in the road. Here's my list of what I've done so far:

1. Oil change and fluid check
2. Wheel balance/ rotation/ alignment (still shook at 70-75 mph)
3. Replaced rear drive TPMS (light still on)
4. Replaced purge valve (CEL was result of evap leak. This resolved CEL)
5. Installed flowmaster 40 duals out back
6. Replaced 20x8.5" factory alloys with 20x9" gloss black wheels (resolved shake at 70-75mph so assuming factor wheels were culprit)

During next oil change I'll have them check the feont control arms and assembly. Something doeant seem right with the steering feel when I hit bumps.

Also I've noticed significant front end bounce when encountering multiple bumps or elevation changes in the pavement when traveling over bridges. I think I need front shocks.

Well, thats my story. Open to suggestions...
 
🍿

I picked up an '08 w/133k on the clock. Drove it ~100 miles to its new home. The TPMS light was on and shortly after purchase the CEL came on. I also noticed steering wheel shake at 70-75mp and that the front end is generally sloppy. Feels like a bag of jello with rocks in it when I encounter significant bumps in the road. Here's my list of what I've done so far:

1. Oil change and fluid check
2. Wheel balance/ rotation/ alignment (still shook at 70-75 mph)
3. Replaced rear drive TPMS (light still on)
4. Replaced purge valve (CEL was result of evap leak. This resolved CEL)
5. Installed flowmaster 40 duals out back
6. Replaced 20x8.5" factory alloys with 20x9" gloss black wheels (resolved shake at 70-75mph so assuming factor wheels were culprit)

During next oil change I'll have them check the feont control arms and assembly. Something doeant seem right with the steering feel when I hit bumps.

Also I've noticed significant front end bounce when encountering multiple bumps or elevation changes in the pavement when traveling over bridges. I think I need front shocks.

Well, thats my story. Open to suggestions...
Shake was likely a simple balance issue on the old wheels. Sometimes weights come loose. Though if someone balanced the old ones and simply a new set fixed the issue, id question how well the old ones were balanced. That doesn't make a ton of sense. Id say the wheel could be out of round, but usually you can see that on a balance machine.

You're probably spot on about the shocks though. Id probably look to be replacing all four if possible. They should have similar life expectancies. These could also play into the steering feel, though the idler/ pitman arms seem to be pretty common on these as well.

Check your drive belts for cracking and wear.

Generally speaking with any used vehicle over 100k i'd suggest going though and changing fluids. Most people dont bother with general maintenance and it's likely due for multiple fluids to be replaced regardless of how they look. Engine and transmission oil is just about the only thing you can expect to sort of be changed on time. Coolant, brake fluid, diff oil (especially the front), transfer case, and power steering fluids are all commonly neglected.

Honestly I dont know that there's a way to know if any of it is truly bad just by looking at it. If it's turning color, that's a sign something is going wrong because the fluid is either getting too hot, or other materials are leeching into it. The additives in fluids break down over time and oils absorb water. If the fluid is low, it has run it's course and should be totally refilled. The diffs are one of those parts that lose fluid over time and people like to top off rather than servicing. Which, i get, it can be expensive, especially if the cover bolts are rusty. But that old oil is concentrated with impurities and small metal bits. Topping off the fluid in is like reusing half your bathwater.



Generally, it's peace of mind knowing the truck is on schedule. You dont know if or when any of your service has been done last unless you have documentation showing otherwise.
 
All good points Raekal, and thanks for your response.

I did get a car fax and it looks like its been in for oil changes every 7500-8K which is a little too long for me but in line with what the manugacturer recommends I think 😕. Also a big maintenance job was performed at ~100K (timing, water pump, ECT....). Like you said, nothing compares to actual documentation though.

I do agree and will likely change out the fluids as I go, just for that piece of mind.

I also questioned the wheel balancing and alignment that the dealership performed and why they did not catch it that it was not right. I will be bringing it up during my next oil change. Good news is that I was looking to switch the wheels out anyway so I'm ecstatic now that the steering wheel doesn't shake at 70. I will however have them check the front end assembly as well.

So, I'm pricing what a get set of shocks installed will run me? A quick Google search posted parts from $200-$700. I'm not sure what labor is looking like but open to suggestions on the possible cost obtaining a better ride?
 
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A set of fox 2.5 is on my list. Should be pretty straight forward to fit yourself if you have experience working on cars.
 
Great points guys.

I just did the transfer case and rear diff fluid yesterday. Oil was grosse. Front diff drivers side seal and bearing to go.
Range AFM disabler should be in today too!
I threw some Marvel Mystery oil in the crankcase and let it run for a few miles. Going to dump the oil soon and then do the plugs. No wires but I’ll likely order some too.
 
Great points guys.

I just did the transfer case and rear diff fluid yesterday. Oil was grosse. Front diff drivers side seal and bearing to go.
Range AFM disabler should be in today too!
I threw some Marvel Mystery oil in the crankcase and let it run for a few miles. Going to dump the oil soon and then do the plugs. No wires but I’ll likely order some too.
Thankfully wires are the easiest part of that job. hah.

However, I don't think you can get the driver's side front diff bearing out without dropping it out of the truck and basically rebuilding it. Plan to replace the seal if it's leaking or look to replace the whole assembly if the bearing is bad.


In this diagram you will see that item 5 is the bearing on the passenger side, there is a matching one on the driver's side on the inner side of part 15 (case half). The only parts outside of that are the seal, oil deflector, and mounting flange.

I believe this is the same for all of the avalanches.
 
If your having any front-end issues...don't forget to check the Intermediate steering shaft. Mine sounded like the whole front end was falling off. Checked all the components and they all appeared in good shape. Tracked it down to the steering shaft. Swapped it out and what a difference. Feels like new and no thumping and loose feel issues. Saved a bunch of time and money by not replacing all front end components like I thought. Make sure to look at it when diagnosing your issue. Many utube view on how to. Did mine in 2 beers.
 
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