Advise for a new member

[Trigger]

I am new to this website and am very excited to get some advise and education to help my vehicles perform at their best. I figure this topic has already been covered, but from what I see everyone on this forum is friendly so here goes:

I have a 2000 Chevy Silverado 2500 HD. It has the 6.0 engine and the heavy duty transmission. It is gas of course by the 6.0. The engine has 120000 miles and I use it to tow often. The weather gets pretty hot here, sometimes over 100 degrees when I tow.

I have done no modifications to my engine. I have always taken it to the local quicky lube shop.

The engine runs great, but when I start it in the mornings I hear a slight knock (lifters?) that is louder when its cold. The knock countinues until the engine warms up a little bit.

I want to do my own lube and filter changes, so here goes. What kind of oil should I use. Synthetic or conventional, what weigth and what brand? Also what filter should I use? I already know I'm gonna do a used oil analisis to find out the condition of my truck.

Also what transmission fliud to use. My manual says I can go 50,000 miles before I change the fliud if I am towing. Does this sound OK? I've always done the fluid change at shorter intervals.

Lastly (and if your still reading this, thanks!) I want to do a engine flush to get all the [censored] out of it. What type of flush is recommended for my truck.

Thanks for the help!

 

[MGregoir]

The Vortec 6000 is notorious for piston slap when cold which may be what you are hearing. If it is lifter noise, a thinner oil on startup like a synthetic 5w30 may help, or an Auto-RX treatment to clean out the lifters.

Most conventional oils for "severe" use like high temperature towing are good between 3000 and 5000 miles, a synthetic would put you in the 5000 to 7500 mile range. I believe the manufacturer recommends 3000 miles for "severe service" like towing.

In summer, 10w30 is fine there, but I know it cools off in northern California in winter, and a 5w30 would be better. A good oil like Pennzoil Platinum 5w30 would likely serve all of your needs well being changed every 5000 miles if the engine is healthy. Healthy being no leaks between the air filter and engine to ingest dust, or coolant leaks.

Solvent engine flushes are generally not recommended but there is a product called Auto-RX that is an oil additive highly regarded here. Takes more time (it works while you drive) but it seems to do a very good job.

For transmission fluid, if you are really concerned, take it to a reputable mechanic and have them flush out all of the fluid with new GM-approved Dexron-VI and change the filter with an OEM (Delco) one. Drain and fill the transmission every 30,000 miles (draining and filling the transmission only replaces part of the fluid) and you should be fine.

 

[Trigger]

Thanks you for your advise. I just looked at the website for the Auto-RX and it looks like a good product. I've never heard of the piston slap. Do you know if there is a cure for it or is it even that harmful? Anything that sounds like metal banging makes me nervous. I'm gonna try the Auto-RX to solve the problem.

 

[dnewton3]

True "piston slap" is not harmful at all. It's quite anoying, but it won't hurt anything. It's very typical of engines that have forged aluminum pistons. They expand at a slightly different rate than the rest of the engine, and so the clearances are a bit "loose" for a time. Hypereutectic pistons do this as well, but to a much smaller degree. It's typical to hear piston slab shortly after the engine is started when cold, until 5-15 minutes later, when it's warmed up. Again, piston-slap will not result in engine damage. It's just bothersome to listen to.

Typical piston-slap engines of note that I personally have been around are the 6.0L Chevys, my 4.7L DOHC Toyota, and the old 5.0L HO engine in Mustangs from around '87 to '92. I'm sure there are many others; I just have experience with these. All of these engines are noted for good longevity, stout performance, and overall decent design.

Now, on to your fluid selection questions:

Regarding your transmission, it's probably the 4L80E (or some variant), which is an updated over-drive HD version of the old TH400; it's a very good transmission. Overall, a good quality DEX III synthetic (your choice of brand) or some DEX VI will do very well in your transmission. Since you're towing frequently in hot temps, I'd suggest you stay away from "conventional" DEX III fluids. It's not a bad choice, but there are better ones.

You didn't mention it, but with 120k miles, it'd be time for a differential fluid flush as well. You didn't say if it's a 4x2 or 4x4. If a 4x4, check the front diff vent cap for compatibility with "synthetic" fluids; it should be white in color for synthetic. If not, the vent cap can be changed, but it's just about as easy to use conventional GL-5 and change it just a bit more often. Unless SEVERELY ABUSED, most differential fluids can go a long time without concern. Since you tow in hot climates, the rear diff is much more of a concern than the front; change it more often.

Regarding the "synthetic versus dino" issue, that's up to you. Synthetics will typically give you longer service intervals, but not necessisarily better used oil analysis. The more you learn about "synthetics" and used oil analysis, the more you'll begin to understand that these are tools for extended drain intervals. Like everything else in life, there are costs and benefits to all choices.

 

[bbslider001]

Just a little input.... I had a 2004 2500HD with the 6.0 before I had my Dmax. I got it new and put about 25k on it before trading it. When I first started driving it, it only got about 13 mpg ona good day. I learned about Amsoil and, long story short, started using the Series 3000 5w30 for extended use and good protection. My used oil analysis were always good and the best part is that my mpg went up to about 15-16 and stayed there consistently for the rest of the time I owned the truck. I did 10k interval changes and used the truck for heavy towing and daily driving. Anyway...just my .02.

 

[Trigger]

Dnewton3, thanks for the info on pistion slap. I feel much better knowing it is not harmful to my engine. My truck is a 4X2 and i just changed the rear diff fluid recently with Royal Purple synthetic. I do have the 4L80E transmission. Is there a specific Synthetic transmission fluid that people on this board like to use? I'm about due for a fluid change.

Cowhorse01, 3MPG difference just by changing oil brands. Thanks, at todays gas prices I'll check that out.

 

[dnewton3]

Seeing as you have 120k miles on the truck, I'll presume you want another 120k miles out of it. With today's vehicles, this is not in any way an absurd expectation.

I would suggest any brand of "synthetic" transmission oil you feel comfortable with. Again, "synthetic" oils do a fantastic job at lasting longer in service, but not necessarily a proportional job of protecting better. As an example, you might get 2x the life from a "synthetic" transmission fluid, but only 5% or 10% better "protection" at temp extremes; it's somewhat a subjective debate. I do fully believe that synthetic fluids are a fantastic choice in EXTREME environments, but most of us don't really operate in such places.

Remeber that your transmission temp is controlled by the heat exchangers in both the radiator, and the supplemental cooler in front (I'm presuming you have the towing package, given the HD nature of the truck and your use). The transmission temp has much more to do with fluid service protection than the base stock. Synthetics can definitely take more heat soaking, but if you have proper operational control of the temps with good equipment, then the temps should never get that "hot" in the first place. In other words, it's likely a better choice to keep the fluid from getting to hot (better cooling), than choosing a fluid that can take more heat, because it's not controlled.

I'll not recommend any brand; that's up to you. I'll suggest good products to choose from. Mobil, Pennzoil, Valvoline, Amsoil, Schaeffers, RP, RL and many others make good fluids. If you're interested in EXTREME transmission fluid capability, then a TES-295 fluid clone like TorqueDrive, 204-SAT, or AutoTrans-5 are fantastic performers, although a bit expensive. I see no real reason to get a licensed TES-295 fluid when a clone performs just as well for less money, and you're not in any Allison Transmission Extended Service Contract (where TES-295 licensed fluids are REQUIRED).