Tranny 'clunk' on startup while in 'P'

[Mark Rinker]

My 2005 GMC Denali has a characteristic 'clunk' that is significant through the passenger compartment on startup. I've gotten used to it, but maybe shouldn't be?

I assume its from torque converter drain back - but maybe its a worn u-joint?

Truck has 140K miles and has the AWD system. What a fuel pig, the 6.0L gas is most efficient in converting gasoline to noise, not torque.

[Yukon6.2]

Hi Mark
My wifes truck is a 03,it has the push button 4x4.
No clunks when it starts.
Warned you about the 6.0 gas pig,how is it compared the the gas plow truck you had for a while?Wasn't it a 6.0 as well?
My wife just used hers to do a "town run". Town is 100 miles away,we don't have any stores where we live except for a liquor store.So it's 200 highway miles and a few hours of running around town.$86.00 gas to fill it,which is 62.4 liters which is 16.5 US gals@5.21 a gal.
When i do the same trip it's $100 +.I'm thinking of looking into some kind of chip or programer to try and get it up some.It's paid for and have a parts truck so she will have it for a while,she refuses to drive the diesel.
Back to the clunk,have you had the trany serviced to look for trash?We had a older 4x4 with a 700 in it that clunked,one day i backed up and that was it,no monument forward or back.
Hope it's not serious,sounds like the boat is going to suck up a few $$$.
Good Luck
Thomas

[Mark Rinker]

Yeah I took the Denali in the deal for selling my biz, so I'd have something to drive. What a marshmallow it is.

Knowing my luck, it will need a transmission soon. You know they go in threes...

:)

[Yukon6.2]

Just got back from a 10 day holiday.
Used the gas pig to go to the airport 100 miles away,we had luggage,3 people and figured we would be bringing back stuff,and grocery's.
So the truck had set for 10 days,and i listened for anything on start up and heard nothing,i'ts got 115K miles on it.
Thomas