Questions on 2005 2500HD Diesel

See my post below from 11/1/04 re: Fuel Gelling in Winter. The group gave very useful information on that topic.

I've heard a product called STANADYNE is good for all year round. There is docs on the web site

describing the products, and indicating GM approves of it. I'd be very interested in feedback on which STANADYNE product anyone has used. BTW, I heard about this product while inquiring about fuel gelling, and fuel line freezes. That bothered me a bit - I get this great truck, can pull what I need, get decent mileage.. and lines freeze in the winter? I"ll get this stuff if it prevents no starts, getting stuck, ice forming in the fuel filter, and whatever else.

Regards, Dom

You ask a lot of reasonable questions, but I'm not opinionated enough (or qualified) to give you answers on several of them, so I'll just touch on one topic - synthetic motor oil and turbos. I own a 2004 Chevy 2500HD crewcab with the diesel and Allison tranny, and the reason I run synthetic oil in my truck is mostly for the turbocharger. Now I realize that synthetics will have better lower temperature performance, decrease engine wear on cold weather start-up, have a lower pour-point, etc. but living in sunny Central Florida mostly negates cold weather issues. What I'm concerned about is the high temps of the turbo, especially on shut down after pulling or high speed runs. Standard oils when exposed to the high temps of a turbos bearings - especially if they contain a lot of products of combustion - will burn and form a coke residue on the bearings if they are not allowed to cool down properly. I use synthetics specifically because they resist much higher temperatures and will not "coke up" my turbo bearings.

On the flip side, the turbocharger is typically at the top of the oil loop and is the last to receive an adequate oil supply during cold start up. This is the main reason why I cringe when I see guys race their turbocharged motors immediately after start up in order to warm it up, build up air pressure, or whatever. I use a synthetic oil because it helps reduce this damage.

I won't make any recommendations as to brand of synthetic oil. I personally believe that all the major name brands offer far more protection than you will ever need in your truck, and I use the brand I do because it is the most convenient to obtain in 15w-40 for me. I change it every 5000 miles.

Just my two cents worth.

Cheers - Jonathan

It all comes down to making sure you know that the fuel you are putting in the truck is of the quality your truck requires. I don't mean 40 or 45 cetane, I'm talking about things like how much fuel does your local station sell? If they don't have a high turnover, ugly stuff tends to grow in the underground tanks that eventually winds up in your filters. Do they blend in the winter to ensure that the gel point is in step with the anticipated cold temperatures?

Rather than drive 3 blocks to the closest station (where I have NEVER seen a vehicle at the diesel pump, I drive 12 miles out of town to the truck stop where I may have to wait for a turn at the pumps. (FWIW, it's also about 15 cents/gal cheaper ;-)

Greg

For you guys with diesel trucks, do yourselves a favor and go to

. A wealth of info primarily about our ( Duramax ) trucks. Personally, I change my oil/filter @ 5k miles, fuel filter and Allison spin on filter @ 10k miles. There are many different opinions on this. By the way, it's a good idea to dump and refill both diff's at 500- 1000 miles with a good synthetic.

Thanks for the info guys....

My understanding is there isn't a Mobil 1 synthetic for diesels... So, I'm gonna have to find something different...

As far as changing the spin-off filter on the transmission, my local NAPA can't find a listing for the thing. I checked at the Chevy dealer and BELIEVE IT OR NOT, they want $29 for the spin-off transmission filter... 'Course they also wanted $24 for the oil filter...

What synthetic oil is everybody using? And what synthetic gear lube? Did I read the manual right that the rear is an 80-90 and the front is a 75-90?

If you can't find the Mobil 1, consider Castrol Premium Blue 2000 synthetic. I get mine at the Cummins engine dealer.

I use Red Line synthetics for all the lubes required - engine, trans, transfer case, diffs, wheel bearings, etc. See my follow-on post "Duramax Diesel"

Dave

You can find folks selling filters for the Allison (and engine oil filters for your Duramax as well) on eBay. An Allison filter runs about $12 a pop.

Mobil-1 does indeed make a 15w-40 and 30wt fully synthetic oil for your diesel, it's just hard (danm near impossible, which is unfortunate) to find the 15w-40 in my area. You can try the local truck stops if you have an interstate nearby. Valvoline makes a fully synthetic 15w-40 which I have found available at my local auto parts dealer in one-gallon jugs. There is also Amsoil, if you want to deal with them. Shipping adds to the overall cost, which for me runs it up to over $6.00/qt when buying a 2 1/2 gallon jug - the exact quantity you need for your Duramax. It costs more, but the delivery is quick and they always have it in stock and is just a phone call away. Finding a quality fully synthetic 15w-40 can sometimes be a hit-or-miss proposition getting it when I need it.

Cheers - Jonathan

The last time I bought an oil filter at my dealer, it was $15. Auto Zone has it for less.

Premium Blue 2000 is made by Valvoline and can also be found at NAPA.

AW

Thanks for the info guys... It looks like I'll probably do the synthetic thing next change... I just did it with the normal Rotella T this time...

I'm gonna have to find a source for the transmission filter though, 'cause I sure can't see paying $29 for the thing from the dealer...

'Course, these are the same people that think the differential grease should be $30/quart... They've gotta be kidding...

You're right. I should have trotted out to the garage and looked at the box first. ;-0

dperez@juno_nospam.com writes

Good luck in your search. I went looking for an air filter for the 03 Cummins/Dodge. Stopped by NAPA...$32 and change. Went by the local dealer...$28 and change. First time I have ever bought an air filter from any dealer.

Advance Auto carries Mobil 1 75w90 gear oil for $8.19 a quart, IIRC. Be careful removing the pan from your AAM rear axle and you'll be able to re-use the gasket. Not sure about the front axle as I have 2WD.

AW

If you are talking about the spin on filter, I just paid $15 at the dealer today for the Allison's external filter. That was with a discount and they are still making money on that! Careful when buying that filter. I purchased a Wix filter over the weekend and it would only work if I left the doughnut type magnet out that was on my original filter. Don't know if they all have the magnet or not, but the Wix filter's holes were almost completely under the magnet. The OEM's holes are closer to the outside edge of the filter and allow flow past the magnet. REALLY glad this is a very simple thing to change since I had to put the old one right back on Sunday until I could return the one and purchase the OEM filter....

Find a truck repair shop that specializes in Allison transmissions. I pay about $8 for mine in Pensacola, FL at a small hole in the wall place that does nothing but Cummins and Allison stuff. They even warned me, DON'T FORGET THE MAGNET!!

Synthetic oil...there's always the Rotella T...comes in both normal and synthetic. Available at Wally World.