07 Yukon Denali, Changed Differential Mounts, etc

[jetman]

07 Yikon Denali w/6.2L and 174k miles

Changed the frt differential mounts (GM# 23104736 & 23104735), and engine mounts to the H3 units (2 x GM# 25847739) , tranny mount (GM# 15840278). Now the "Clunk" is gone when transitioning on and off the gas pedal.

I know for sure the frt differential mount bushings were dead. Tranny mount was fine, they're bullet proof. I'm not sure if my engine mounts were dead or not? They are fluid filled and are known to leak.

While I had things torn apart I changed all 4 O2 sensors, and both knock sensors. I alsoropped the tranny pan and changed the atf and filter(I posted the results here on BITOG in the used atf area ).

I have a lift. To do this job Itook the front wheels off, inner fender liners out, sway bar out, front driveshaft out, cross member out, exhaust Y pipe out.

I don't have a tall transmission jack, so I lowered the lift down close to the floor and used a HF lawn mower jack to drop and reinstall the frt diff.

 

[Oillover]

Let us know how it drives once you have it packaged up.

 

[gman2304]

Very nice, clean, well organized shop. Well done! Pics of “the beast” please?

 

[jetman]

It drives great! No more "CLUNK".

It's stock appearing. Here's a pic on the lift during this mx, and another before I took the grill guard off.

 

[Jim_Truett]

Even with all new mounts I get a bit of a clunk as you describe, but mine is from total driveline backlash, including the planetary in the transfer case.

 

[c502cid]

I love how you marked the floor for each of your vehicles being in the right spot for the lift!

 

[jetman]

Even with all new mounts I get a bit of a clunk as you describe, but mine is from total driveline backlash, including the planetary in the transfer case.

174k miles
I too always thought my "clunk" was caused by slop/slack in the drive train (xfer case, diffs), but my clunk is gone now. YEAH!!
I might rebuild the xfer case someday.

 

[Jim_Truett]

I put a chain and bearings in my transfer case at 185k. The parts I took out were still quite serviceable, but the previous owner was pretty good with maintenance.

 

[Duffyjr]

@jetman I like the color of your truck with the tinted windows, what color is that?

 

[jetman]

Here's are the glovebox RPO codes:
51U - EXTERIOR COLOR,PRIMARY,SEDONA TAN
51U - EXTERIOR COLOR,PRIMARY,TOREADOR RED MET
51U - PRIMARY COLOR EXTERIOR, GOLD MIST ME

All 3? so your guess is as good as mine?

 

[Jim_Truett]

Here's are the glovebox RPO codes:
51U - EXTERIOR COLOR,PRIMARY,SEDONA TAN
51U - EXTERIOR COLOR,PRIMARY,TOREADOR RED MET
51U - PRIMARY COLOR EXTERIOR, GOLD MIST ME

All 3? so your guess is as good as mine?

It looks like Fine Silver Birch Metallic, just like mine. Is there a code 926L on your door sticker, or the RPO label?

 

[jetman]

It looks like Fine Silver Birch Metallic, just like mine. Is there a code 926L on your door sticker, or the RPO label?

I'll check?

 

[Duffyjr]

Here's are the glovebox RPO codes:
51U - EXTERIOR COLOR,PRIMARY,SEDONA TAN
51U - EXTERIOR COLOR,PRIMARY,TOREADOR RED MET
51U - PRIMARY COLOR EXTERIOR, GOLD MIST ME

All 3? so your guess is as good as mine?

It looks like my 08 Lucerne which is Gold Mist but my monitor is not calibrated and it looked a little lighter due to the darker glass.

 

[dan_erickson]

Was there a way to visually see the bad differential mounts? I always wondered if mine were bad on my 13 Tahoe because I also get the occasional clunk that could be felt in the floor at times

 

[jetman]

Was there a way to visually see the bad differential mounts? I always wondered if mine were bad on my 13 Tahoe because I also get the occasional clunk that could be felt in the floor at times

Yes I was underneath it changing the oil and filter and I could grab the front driveshaft near the pinion and pull up and down and get/see significant movement at the bolts that go thru the bushings in the mounts.