I am new Duramax owner (first ever Dieselhttp://dieselplace.com/forum/smileys/Big%20Smile.gif) and would like some advice and experience...


I installed the Amsoil air filter (and am very pleased).http://dieselplace.com/forum/smileys/Clap.gif


At my first oil change, I think that I'll go to the Amsoil synthetic and begin sampling from there on (any thoughts?)


I've overheard some stuff about the differential? (maybe transmission) oil. What should I use and when should it be changed?


I'm thinking about the Nicktane fuel filter next (should I?)


Sometime in the next year or so, I may go with the Edge Juice with Attitude and maybe a Magnaflow or Bank 4" exhaust? (hmmmm?)


Any help and advice that you have would be appreciated...


Thanks in advance

GM seems to use ~2 quarts of differential fluid from the factory. The service spec is 4 quarts. Why? damnifIknow!

I highly recommend draining & refilling the differential within a year of driving off the lot. I did mine after a few months at ~5,000 miles. I saw a significant amount of "stuff" in the fluid, plus a bunch of powder & a few small chunks attached to the drain plug magnet. There is a break-in period for the rear end gears, and the fluid should be changed after this initial high wear period.

Changing the fluid is very easy. The G80 locking diff'l has both a drain and a fill plug. The main question that people have is what fluid to use. The GM recommended "grape juice" is good stuff. It just costs $20-$30 a quart. I bit the bullet and used it.

Get the Nicktane filter? Yes - that or some other good fuel filter. Fuel needs better filtration than the factory filter; sooner or later you'll get a bad fill and the extra filtration will keep the crap out of expensive parts. I happened to buy the Kennedy solution before I heard about the Nicktane filter. From what I can tell, the Nicktane filter is an excellent solution.

The Juice/Attitude is nice to have! It does provide noticably more "Oomph". The Duramax is a nice driving engine, and the Juice makes it more so. I think it's worth what I paid for it. I don't yet have a 4" exhaust. I have also seen significant back-down when on level-5 due to high EGT. I typically drive it at level-2 and have not seen any back-down even while towing or under spirited driving.

First, top of your diff(s) NOW! They are all low when you drive off the lot. Then change them at 5000 for rear and after some use on the front (if applicable). You might want to change the rear diff instead of topping off the first time if you are at say 2k or more. You can use Amsoil or Mobil gear lube and it works just as good for a whole lot cheaper. Synthetic on the rear is a requirement. After that you can go 50k for sever and 100k for light duty and 25k if your are retentive. http://www.dieselplace.com/forum/smileys/Geek.gif


When is your "first oil change"? I would change early, like 1500 or 2000 miles to get the junk out. I would also wait until 5000 at least before switching to synthetic. I went to 10k personally. More frequent early changes will reduce your Silicon and wear metals faster on your analysis. I run synthetic oil with a dual remote bypass and change ~7500. All analysis has looked good.


Get a secondary fuel filter. It doesn't really matter if it is pre or post, Kennedy or Nicktane, just get one and get it on NOW! I do have a position preference and that is post OEM, BUT I would rather a pre than nothing. I actually have both. http://www.dieselplace.com/forum/smileys/Embarrased.gif


If you are seeing temps at say 210 plus on a regular basis on your tranny, change to synthetic. Mobil 1 is the only one that I have not seen anyone say something bad about. Transynd has turned funny colors and Amsoil has caused slipping. Now, those issues seem to be few and far between, but have been reported. Search is you friend on this side.


A larger free flowing exhaust is good to get before you add the J/A, but if you install the EGT probe, it is not required. If you use another tuner, then a separate EGT gauge is needed and you will have to watch when you play as it won't control itself. Again, search is your friend.


You might also search on air filter tests as a memeber did a bunch of work that shows the OEM is the best way to go for our trucks. I have an Amsoil that is going in the trash next week. I have to admit I was surpised with his results, but can't argue the data as the other stuff from the manufacturers is propaganda.


My best advice is to search and read ...... a lot! But make sure the wife doesn't get too hacked at all the time and money you will spend. http://www.dieselplace.com/forum/smileys/HiHi.gif

extra_miles,


First thing you better do is take out your AMSOIL filter, get a bunch of paper towles and soak up the excess oil from the filter. When I installed mine I was unaware that AMSOIL soaks their filters to the Nth degree and consequently that oil can get sucked into the intake and coat your flow sensor with oil. If this happens you will either have to clean it(if you are lucky) or you will be buying a new sensor (not covered under warranty because it's the fault of the aftermarket filter). I was lucky someone on the forum here mentioned that and all though my airbox was full of oil it never got to the sensor. Good luck and welcome to the forum.


JP

I'll second or third or fourth topping off your differential. Mine was a full quart low, so I'd buy 2 quarts to be safe. I went 750 miles before I had a good opportunity to top it off. (I had a hard time getting the grape juice since dealers are few and far between out here.) I can't imagine that I did any damage, but it still really pisses me off!


Oh well, what do you expect for $40,000 + ?

kn filters are rated the WORST air filter followed next by UNI.

Change the diff oil to syn. Diffs are 1/2 full from factory.
Amsoil is not ch/ci4 rated. Mine started burning like mad at 5500k. I believe it had broken down.

Use nictane pre-fuel filter.
Use ac delco air filter (rated the best).
Watch you oil pressure with syn engine oil mine dropped to 12 lbs hot.

My Amsoil filter is not going in the trash and my oil pressure has never changed with two different brands of synthetic. AAM recommends changing the rear end oil after 500 towing miles. The Eaton locker puts a lot of disc particles initially in the oil. Mine was black at 2500 and the Mobil 1 looked new at 25K. Later! Frank

extra_miles,

My advice is to jettison the Amsoil filter and go back to stock AC Delco. Some members of this board put in a ton of hours doing independent filter testing with 9 brands and here's the results:

http://www.dieselplace.com/forum/uploads/24D_chart.jpg

If you want to read the whole story behind these numbers:

previous Dieselplace thread on air filter testing (http://dieselplace.com/forum/forum_posts.asp?TID=10642&PN=5)

If Transyndy turns a FUNNY COLOR then theres a problem with the tranny not with Transynd, for that matter THERES A PROBLEM if any tranny fluid turns a FUNNY COLOR, the second best test is sniff the tranny dip stick if the fluid smells burnt, either fix the tranny or replace the tranny fluid. By faithfully changing the tranny fluid at designated intervals or more frequently you will avoid all kinds of problems.


good luck