Info needed: 1967 M38A1 Lubrication?

[Les Kovacs]

New to MLU and require info as to lubricants used in a stock 1967 M38A1-many websites-original manual and lots of confusing info out there...so here goes.

Motor oil?

Transmission/Transfer case?

Steering box?

Axles?

And....front wheel/axle universals/hubs?

Many thanks.

lk

[rob love]

Motor oil: When I was in the military we made a bunch of changes in the oil used. First it was 10W in the winter and 30W in the summer. Later we went to 10W30, and in the early 80s changed over to 15W40 all year round. The 15W40 was actually kind of heavy for the winter. Since those days, the oils have changed specifications many times, and with the removal of the zinc in the last decade from the gasoline specification, I would recommend either 10W30 with a Zinc additive, or 10W30 high mileage oil like you get from Cdn tire. Better yet would be to use oil meant for diesel engines, but that will somewhat limit most of your choices to the 15W40 class of oil. If your vehicle is primarily a summer vehicle, you actually would be fine with a diesel 15W40.

For the gearboxes, 80W90 gear oil will do just fine. We used an older specification of oil back then, so a GL3 rated oil would be best, but quite frankly you won't have any problems with a GL4 in a Jeep.

We used to use gear oil in the steering boxes, but we also used to change a lot of steering boxes for seals and wear. I would recommend a mix of grease and oil to the consistency of thick soup.

Steering knuckles were just grease, automotive, artillery. The army went to a synthetic Grease, Artilery and Automotive in the late 80s, and it was very good. I cannot say the same for the earlier non-synthetic stuff. The synthetic had a much wider range of operating temperature, resists water better, and maintains it's consistency. Any regular tubes of multi-purpose grease will work out fine, but I would suggest picking one, doing the complete cleaning of bearings and knuckles and repacking, and then sticking to that one grease.

There are likely going to be a couple of problem areas with your first major lubrication of your Jeep. The first will be your rear wheel bearings. They are not oil fed, they are greased. It is a fairly major job to remove the axles and repack those bearings. Odds are that when you open it all up, you are going to find that the bearings have not been repacked in a very very long time and will be pitted. It is more a job for a mechanic experienced with Jeeps than a driveway job. You'll need a special puller for the hubs on a Cdn2, and you'll also have to remove the brake lines form the backing plates. Almost invariably, the brake lines will be rusted to the cylinder, so you will break them. You'll need inner seals, outer seals, a press to install the rear bearings, and a dial gauge and the shim kit to properly pre-load the end play on the bearings. This job is not for the novice. A 5 pound hammer is not a substitute for pullers and presses. And ignoring those rear bearings will only eventually result in either the bearings seizing up, or burning up and an axle coming out the side of the vehicle when it's not supposed to. Undertorquing the large nut on the end of the axle can result in the hub working loose form the shaft, and requiring a new axle shaft and hub.

The next thing your jeep will likely need, and you will find this if you go to re-pack the front axle U joints, will be the king pin bearings. They tend to rust and pit from neglect. That is another fairly involved project, and you will want a good set of digital calipers or a micrometer to set up your shim paks, along with a spring scale to set up the preload.

Odds are your bellcrank will also need attention beyond greasing.

The fortunate thing about a Cdn2 is that replacement parts are common, there is very little that you cannot buy for them off places like ebay or any of the multitude of Jeep suppliers. Even the closed shackle kits are now being produced.

[Wayne Hingley]

Originally Posted by rob love

...I would recommend either 10W30 with a Zinc additive, or 10W30 high mileage oil like you get from Cdn tire. Better yet would be to use oil meant for diesel engines, but that will somewhat limit most of your choices to the 15W40 class of oil. If your vehicle is primarily a summer vehicle, you actually would be fine with a diesel 15W40.

Further to Rob's comments on engine oil for Diesels, Shell makes a Rotella 10w30 for Diesel engines. I have been using it in my tractor. I'm not sure what exactly is in the additive pack , but I will try to find out, as I may begin using that oil in my jeep.

[rob love]

The diesels have the normal amounts of ZDDP, now lacking in the modern gasoline oils. That is hard on the flat tappets, although more so in the high compression engines with more radical cams.

[Les Kovacs]

Wow....thanks for all the input Rob and Wayne. Ok....one thing left out in your reply Rob and that are the differentials but I am assuming that you bundled them with the "gear boxes". Wow...a load of knowledge!

Ok, some history....my 67' CDN2 apparently came from CFB Petawawa....a retired military mechanic (John Power) restored it from 2009 to 2011(I have a ton of pictures from him)...he sold it to a OPP cop in Fort Erie in 2015 and I just purchased it last weekend....the OPP cop only put on 600 miles (1000k) in the two years he owned it. So, I am assuming that Mr. Power greased the axles on assembly as per the pictures it was a frame off restoration.
I plan on doing all of the lubing aside from the kingpin, front & rear axles. Do know of anyone in the Barrie area that may have knowledge and experience of working on jeeps aside from Willy's Acres of whom I have major issues with?

Thanks for the great advice.

les

[rob love]

Differentials, transmission, transfer case are all 80W90 hypoid, preferably GL3 but that is now hard to find. It is said that the GL4 is hard on the brass parts, such as the synchros in the transmission on 2 and 3 gear. Some of the synthetics are rated GL3 such as royal purple, but you may find the synthetics tend to leak a little more.

I see on your other thread some of the parts you are looking for. Hard to believe that it had a frame up restoration but needs

pitman arm, draglink, bellcrank (and hardware), thermostat (which one?) as well as parts for the steering box

I would suggest you check your kingpins.

Easy way to check them is you jack the truck up, remove the wheels, and disconnect the knuckle from the tie rod. Then turn the knuckle thru it's ranges and if it feels rough, then you need the bearings.

If your Jeep has the incredible uncontrollable wobble, it is often a combination of wear in all of the steering system, kingpin bearings included.

The kingpin bearing and cone are pn 11590/11520. If you buy them up here they will easily run you $30 each. Off ebay you should be able to get them for about $10 each. http://www.ebay.com/itm/11590-11520-...sAAOSwstxVUfDD