accepatable fluid substitutions

I had read that when the manuals were made, fluid specs were much different. So is there a definitve list of what oils, coolants, gear lubes, etc. are acceptable for use in these trucks? I don't want any of this energy star compliant crap they're pushing these days <img src="emoticons/icon_smile_big.gif" alt="Big Smile">

You are going to get a lot of different opinions on the gear lube issue, GL1 vs GL5. The story goes that GL5, your typical modern gear lube thats available everywhere, has EP (extreme pressure) additives in it that will attack synchros in your t/case and trans. Remember, the deuce t/case is synchronized. Some will say they have run GL5 in a synchro'd trans for years with no problems. The axles should not have a problem with it, though.

GL1 may be harder to find in the appropriate weight. I worked on my local auto supply house for 2-3 months before they got some. None of the Tractor Supply Co or similar places had it.

Regarding engine coolant, use low silicate coolant made for diesels, and ck your Ph levels, adding the diesel coolant supplement if necessary. Not doing this CAN lead to cavitation (pitting) in the cylinder liner walls.

For engine oil, be sure you use a diesel rated oil (CH-4 or CI-4). Rotella 15w-40 is the most common stuff available just about anywhere. They even sell it at Sam's club here for roughly $35 for 6 gallons, enough for one oil change.

I had a winch that the GIs decided muddy water was a suitable substitute for 90 weight.........

i had the issues of tryin to find the GL-1. i gave up and dumped some GL-5 in the trans and i havent experienced any problems. i even have had heavy loads in the truck and noticed no difference in the way it shifts

rattlehead, what brand and weight is the GL-1 you aqquired? where did you finally get it from?

Anyone trying synthetics? The guys at the Zone swear by them for the M715s.

I have a nice inventory of GL-1 in 5-gallon pails. No shipping, but I can deliver to the East Coast (Aberdeen Rally).
As to antifreeze, just check the label and make sure it's Mack and/or Cummins certified.

Big Mike,

It was 90w made by Super S. A locally owned auto parts store finally got some in.

So as I understand it: GL-1 is good, if you can find it. GL-5 is bad because of pitting the brass. Valvoline meets mil spec 2105 but is a GL-4/5. I'm so confused.

How do you check the PH of the coolant, is there a test kit?

Also if someone could tell me what type of grease can be subsituted for GAA as mentioned in the lube order.

Will the packaging have the mil spec on it?

I have used "Cooltrak" for testing the coolant, checks pH and freeze point.
Fleetguard has a kit , but I think it's only good for Fleetguard coolants/aditives.
Cooltrak is about $8.00 for 50 strips, google it.
For more info, check out MVM June 2005 for a 6-page article.

GI's think alot of that muddy water lube.
they also think sand works good to filter the fuel. all 3 of my filter bowls had 2"
in them when i got my last truck. And I think it was a motor pool maint truck.
Jason

I forgot the actual rating or certification but I heard that if you get GL5 with a certain certification it would not mess with the brass in the trans and tranfer case. Anyone else know please speak up. I will try to find the rating but I thought it was something like MT or MP?

I think its GL-5 with an MT-1 rating.

Yes that is what I was talking about. I got mine from either Sam's Club or Walmart. I can't remember which.

Its cooltrak.com for the coolant test kit, thanks for the help.

So GL-5 with a MT-1 rating for the gear lube.

Thanks everybody

Does anybody know a good equilivant for the GAA grease?

Or should I just look for the mil spec number on the label?

Stiches, I started using marine grease. EP-2 rating. I've noticed it doesen't wash out when the truck goes swimming. Although i still do a complete lube job after fording, there is less of a worry on the trip home. I've used castrol hypiod-c 85-90w GL-5 gear oil in everything since the FD got the truck in 1997. I've also used it in all the FD's M35's for 9 years with no problems. I've never checked to see if it was MT-1 rated. I've heard of GL-5 causing problems, But i haven't been able to find it anywhere around here.

Well the fog is starting to clear. Thanks Ken I'll try marine grease.

If you do wheel bearings, keep in mind that any of the "high pressure" greases rated for use on automotive disc brake systems are usually made from metallic soaps and are not compatable with gear oil. And you WILL get gear oil in your hubs. When mixed, you get a stiff, non-lubricating gunk.

Plain old light tan long-fiber grease is all you need, the rotating speed of the bearings will not require anything fancier.

As a service note, the little cork wedge usually worshipped as nebulous and/or unobtainable is a joke. Hit a lick with RTV red in the spindle groove after bearing and before locknuts and call it done.

dg