Diablosport Forums

Ok 1st question. my 07 silverado 5.3 2wd started having a clunk problem. when I come to a complete stop its either instant or can be up to 20 seconds later but I will get this clunk. I actually look behind me to see if someone hit me!! It feels like a driveline problem but the slip yoke is not greaseable on the new trk. It will then clunk again after I let off the brake . Could this be anyway related to the tune that I had installed(mikel hooked me up with a 87 tune with knock sensor adjustment and shut off the afm)
It started doing this about a week after I installed the tune

2nd I see there is a new update for my u7194. do I just download it into my predator then upload into my truck. or do I need to put the stock tune in then download the update, then reinstall into my truck.

3rd. Once I do the update will I lose the custom tune you gave me?

4th You state the new update has an option to shut off the afm/dod is this a seperate option just by itself now?? So I could have a stock tune and just shut off the dod??

Thanks!! Kris

1. Does not sound tune related at all.
Easy way to tell is to put the stock tune back in and drive it.
2. The new update has all the changes I made in your custom tune.
Restore the stock tune to the truck, update it, and then install the 87 octane tune with the DOD off.
3. No, you should have it saved to your PC, but it will be erased from the tool when you restore the backup.
But like I said, you dont really need it anymore.
4. Yes, you can do it to the stock tune if you desired (but why?).

Thanks

cool, I still have the tune you sent me saved! Thanks!

maybe a dumb question but where is the option to re install the factory pcm tune? All I see on mine is custom tune? U7194

Kris,
That clunk sounds just like the slip yoke/axel wrap issue. The dealer pulled my drive shaft and greased the yoke on my 2007 SD; the clunk went away and has been gone for going on 12,000 miles. GM has had the issue for years (since 1973)! There is a replacement nickel plated slip yoke if the lube does not help.
Rusty

so they due have a revised slip yoke then?? my dealer keeps telling me they have lubed a couple with no fix and that its normal. I find that hard to believe. That clunk is bad and shouldnt happen on a new truck. I had the problem with my 03 1500 but that one was greaseable.

Kris,
I am no mechanic, but I think the design is still the same on the 2007 as the 2003 (I really think it has not changed for the 1/2ton, light duty, trucks since 1973). I don't think there has ever been a zerk fitting on the slip yoke assembly. I do know they can grease the slip yoke by pulling it out. There was also a TSB out in the last couple of years that called for the nickel plated unit.

A quick test is to put enought weight near the tailgate to lower the truck about 2 inches, then try it out. The weight will compress the springs and limit the axel wrap.

Ill give that a shot. The older silverados up to the 06 classic had a zerk on the slip yoke which was nice. The nbs trucks only have 2(outer tie rod ends) Im at 10k miles and am having my upper ball joint replaced on the driver side. I hate sealed joints like that!! Thanks for your advice though! Ill give that load test a shot like you mentioned

My 07 NBS does the same thing, i always look to see if someone hit me, i think mine did it before the tune too but not 100% I wonder what gm says about it.