Two questions

[Z71GUY]

This weekend I did a few things to my truck that made a good bit of difference in how it idles and how smoothly the engine runs.  Not sure which one played the biggest part, but all I know is this beast runs alot better.  My G/F noticed the biggest difference was the idle....much smoother.

 

I replaced my fuel filter, spark plugs (Bosch Platinum), changed the oil and ran some Chevron fuel injector cleaner.  One thing I noticed is that 6 of my 8 plugs had gaps around .75-.80.  Much larger than the .60 that is requested by the service manual.  Glad I didn't run these plugs to the recommended 100,000 miles!  

 

Now to my questions.  The first thing I noticed was that I seem to have a small tranny leak.  The leak seems to be right where my drive shaft/yoke goes into the transmission.  I'm going to be taking it in soon for a tranny flush, is this going to be expensive?  I'm not very familiar with trannys....any ideas what could be causing this.

 

Also I have this strange rattle/noise coming from my dash area.  Sounds like it is deep inside the dash near where the firewall would meet it.  Kinda sounds like marbles moving around...hard to explain.  This noise only shows up when I am accelerating under load...and sometimes I can hear it when I rev then engine at idle.

 

Any input to these questions would be appreciated very much!  Thanks...

 

BTW my truck has 41,000 miles on it....

[Black02Silverado]

Now to my questions.  The first thing I noticed was that I seem to have a small tranny leak.  The leak seems to be right where my drive shaft/yoke goes into the transmission.  

If it is that seal where your Yoke goes into the tranny then it is easy to change out. All you have to do is remove the old seal and install a new one. You can either use a seal puller, (Auto Zone will let you use one, have to put a deposit down but you get it back when you take the tool back) or you can just do the shade tree method and use a  screw driver and hammer, being careful not to mark up the housing of the transmission. Then once it is out just tap the new seal into place, lube up your drive shaft yoke and install it.

 

You might want to check out the yoke where it rides on the seal and check to make sure there isn't a goove worn into it. There shouldn't be one but it doesn't hurt to check. If for some reason there is a groove you can get a repair kit, (speedy sleeve) to go over the yoke so that the new seal has a clean surface to ride on and keep a good seal.

 

Now as for the dealer to change out the seal, it will more than likely cost you at least an hours worth of labor, here it is going for $64 an hour.

 

[Z71GUY]

Well I figured the dealer would charge the full hour of labor.  I had a feeling it would be a seal or something like that...but was not sure.

 

Thanks for the info!

[Import Hater]

The slip yoke seal is a pretty easy part to change out.

 

But I really replied because I don't quite agree with going with the Bosch Platinums.  I've found the standard Bosch Platinum to wear out fast.  And they're much more prone to fouling than any other platinum plug I've seen.  I would go with a double platinum plug from Autolite or Champion.  And don't forget the ACDelco stuff either.  I think the newer Bosch Platinum +4 is pretty decent, but it's track record is unproven.

 

Rob

[burgundyz71]

Also I believe the dash rattle is a common problem on the 99, should be a tsb somewhere on here I believe I read it when I had my 99 but can't recall what the fix was.

[Z71GUY]

I agree with the Bosch Platinums.  After I pulled out a few plugs just to look at them, ANY plug would have worked well.  Just so happen that my local auto parts store only had these in stock, they would have to order the AC Delco's or any of the other "copper" plugs.  I'll just order them online next time I pull the plugs (30,000 miles or sooner).  Either way, my truck idles MUCH smoother due to these plugs.  My stockers were very bad...looked very burnt, dirty and the gaps were around .80...way off from the .60.

 

If anyone knows what the TSB is, I would appreciate it.

 

Thanks,

Eric Anglum

[bigblackdog]

The rattle noise you hear sounds exactly the same as my truck. I bought it to the dealer (still unde warranty) they thought it was knock sensors, but replacing them did no good. Then they decarboned the engine thinking it was pinging, still no good. That is when they called GM and were told it was a noise associated with the piston slap issue. Mine only rattles on acceleration, medium to hard, not when parked and revved up. End result was they said it cant be fixed so I got a 6 yr 100k warranty on the engine at no charge. Great engine except for that ******* rattle!

[Fishhunter911]

 I think the newer Bosch Platinum +4 is pretty decent, but it's track record is unproven.

Just a side note.. I have been told the Bosch +4s were designed for engines with DOHC... at least that is what I was told.. mostly for NON-domestic cars

[woodrow]

my 01 chevy 1/2 ton with a 5.3 only rattles when you are going down the road and put it to the floor then it starts. but i don't have warr. anymore so i can't do anything.

[Z71GUY]

Its not a knocking noise....I've heard that before in other vehicles.  My noise is more of a "rattle" deep inside the dash.  Once we get a good weekend, I may just start ripping & tearing.  Seems like there might be a few other people with this same problem...   ???

[cyclejerk]

Could the rattling noise be the "gurgling heater core" noise they have a TSB out for?

The coolant seems to make noises during acceleration/water pump speed up. ???

[burgundyz71]

I believe the rattle fix had something to do with the drivers side vent needing some padding up by the firewall.

[Z71GUY]

I believe the rattle fix had something to do with the drivers side vent needing some padding up by the firewall.

I think this may be it.  Tonight I located the noise to be on the passenger side (very close to the light sensor).  I guess I'll have to open her up and see whats going on in there.  It defiantly sounds more like a rattle I think...

 

I did try the fix that MountaineerTomZ71 (?) posted awhile back (did a search).  I think I did it correctly...warm the truck up with the cap off of the coolant tank...rev it up a bit, then put the cap back on.   ???   Didnt do anything...

[bigblackdog]

My rattling noise is definately engine caused. It only happens on acceleration, especially under load. This weekend I was bringing home topsoil and the rattling was more pronounced than when the box is empty. It is NOT a knocking noise, but a hard to describe pinging/rattling.  I bought highest octane fuel available and it makes no difference. Dealer put it on computer analyzer and he says everything is in normal range so dont worry since they "gave" me an extended warranty. I think I paid for that warranty when I plunked down $28,000 for a supposedly perfect engine.