New Owner, M923a1, Need some direction

[thegreydog]

After months of reading the forums and researching I decided on the M923A1 and picked one up a couple months ago. The truck is a 1985 with 2000 miles. For the most part, everything is in pretty good shape, but the maintenance seems to be lacking and I want to catch it up before restoring. I have time and some money to get stuff done, but have not been able to pin down what all I need to do. Here is what I got on my list.

• Tires: 16.00r20 XZL, the guy I bought the truck from had these installed. I cannot find an air chuck or gauge that fits these. The stem is almost the exact size as the internal diameter of the chuck. Also, what pressure am I suppose to run on these, mainly highway driving/light offroad
• Oil: Is it 10w40? What brand? Is Napa – 1954 and 27 quarts right?
• Trans: Also 10w40? I have external filter Napa – 1268 and internal Napa – 1892 with 17 quarts? Do I need to change filter or just do a drain and fill?
• Vibration: At idle, she purrs, but when I put her in gear, I get a heavy vibration until I give her some gas.
• Insulation: Under hood, pretty much missing/removed is it necessary? Replacement?
• Windows: I am missing pieces of side window seals around frame and in door, haven't had much luck finding reference to parts. The windows move in/out and and don't sit right with door shut and window up. Also, with the front windows, the seals are dry rotted and water rolls in rain.

Thank you for taking a look and if you have anything to share, I would really appreciate it. I have a lot of manuals downloaded and I have searched these items, but they all come up unrelated to my question or I find several different answers. Thus far the truck has been lots of fun and I enjoy getting Tapatalk notifications to y'alls five ton post.

Thanks!

 

[Gunzy]

Tire pressures should be in the TM.
Engine oil I use 15W40 that is diesel spec and capacity is on you dash data plate and in TM.
Trans oil I stayed with a 10wt eng oil. Check your fluid on the dipstick. If it is red it is Dexron III, if yellow/light brown its 10wt. Also if it looks clean you probably don't need to change it, cap. will be on data plate and in TM.
Vibration I think is somewhat normal, others will know better.
Hood insulation will have to be found used or try looking at what may work from a hardware store.
Window seals will take some looking and maybe a little luck.
Hope this helps.

 

[goldneagle]

Hood insulation is not required. It is falling off all 3 of my M939 series trucks. Window weatherstripping for the truck (side windows is all the same on most of out 2-1/2 ton to 5 ton trucks) they all have the same doors. Erik's Military surplus should have the parts you need.

In case you have not experienced it, if you hear a loud humming sound coming from under the hood when the engine is running, it is probably the cooling fan kicking in. It make a real loud racket when running.

 

[RedBlok]

Eriks has the weather seals in a kit. Also look at the window guides on the doors, my windows lean outward when rolled up and don't even touch the seals, plus it they did they are somewhat dry rotted. Eastern Surplus and a couple of the other vendors listed on this site have some of the parts you are looking for. Download the TM's from this site. The Army did a great job putting them together and the basic soldier can follow them. Good Luck and enjoy the truck.

 

[stampy]

You might look into sheet Kflex insulation/sound deadener for under the hood. While not required by any means it will quiet the truck some. I have some but I am sure shipping would be expensive, best to look around in Ga for it

 

[Another Ahab]

You might look into sheet Kflex insulation/sound deadener for under the hood. While not required by any means it will quiet the truck some. /QUOTE]

I'll start another thread about this to avoid a hijack, and in the meantime:

-Welcome to you, thegraydog, from up here in the Old Dominion State of Virginia.

 

[thegreydog]

This is all I have left.


The tires are 1600r20 XZL, 53" I cannot find a tire air chuck to fit valve stems, nor can I find which PSI to run front/rear
What oil do I use in Engine/Trans? I have seen several different suggestions
When I put into gear I get a heavy vibration, I have read that there maybe something that needs adjusted


Thank you to all who has chimed in!

 

[stampy]

oil depends on what color it is for the trans if its red its dextron if its gold its 10wt as said above 15/40 for the oil which is standard for most diesel trucks. Vibration could be a lot of things from a stuck brake to unbalanced drive shaft, bad trans, bad tire, low tire. You will need to do more trouble shooting before anyone can help you there.

 

[Cruceno]

Grey dog,

I don't have XZL's, so I can't say for sure. Check to make sure it isn't printed on the side of the tire, otherwise search for the info, I'm sure others have mentioned it.

I use Rotella, 15w40 in all my trucks along with the appropriate amount of Lucas oil stabilizer. Works great and really quiets down the noise. Two thumbs up from me. Others will swear by Delo or Amsoil or others...there are dozens of threads on this one. Basically, find a brand made for heavy diesel trucks, buy it, and drive on.

I think we need a little more info about your 'noise'. Prior to shifting into gear, is your idle between 600-650 RPM? After you put the tranny into gear, but before you apply gas, is the noise constant? Or intermittent? Your idle will drop some after shifting into gear, and an intermittent noise is normal as the fan cycles on and off. Give us a little better info and we can help you a little better.

 

[thegreydog]

I think I posted between your post.

The only thing on the tire says 110 PSI Max. I have heard everything from 50 to max. None of my air chucks fit valve stems anyway, which is another problem.

With the Oil I have read 10w40 and 15w40, I have Lucas treatment ready to go.

With the trans I have seen 10wt and others say run 10w40

The noise is more of a vibration, it is when I put it in gear and it goes away once the RPMs around 700

I appreciate all of your guys input, I have searched and searched.

 

[Gunzy]

10w40 or 15w40 will be good in engine as long as it is class'd for diesel engines. I have had a trans builder say NOT to run multi weight oils(10w40 etc.) in trans. so I will stick with a straight 10wt there unless it is red then Dexrom III. On the tires you should be able to run the same pressures as in the 14.00x20 tires. Can't advise on the chuck other then going to a truck shop and see if they can get you one. Is your engine the NHC250? They have a little vibration at idle in gear do to the way fuel is delivered. There is a mod that will apply fuel to the front and rear heads that is said to smooth out the idle but I haven't done it to verify.

 

[Cruceno]

Can you point me in the direction of that mod, Gunzy? I'm not familiar with it

 

[jw4x4]

I don't know how to post a link to it. Just search for "dual fuel line 250" and a bunch of threads will pop up.

 

[Gunzy]

Ya, do what jw4x4 said and you'll find it. Several guys have talked about it and a few have reported on doing it. They usually talk about it smoothing the idle out and some say they get a little more HP.

 

[M35A2-AZ]

You can get the valve adapters at a good truck tire shop, they cost about $3.

 

[thegreydog]

I picked up Rotella 15w40 on sale for $12.99/Gal today for my oil change. I have checked several parts houses and cannot find 10w oil for my trans, everyone keeps pushing me to Hydraulic oil and Ihave been advised not to use it.

 

[wsucougarx]

10wt can be had at NAPA.

 

[thegreydog]

Napa said the only thing they had was hydraulic 10w not oil. I checked with both in my area. The hydraulic was Super Trac 303. Was real nervous and never got a straight answer so I moved on

 

[juanprado]

tractor supply sells it if you have one close by?

 

[thegreydog]

I do have one. The whole Super Trac thing made me nervous. I just want to make sure I do it right from the start. Just to clarify, I want a 10wt oil, not hydraulic 10w.