Vladislav

Hi and welcome to the group!

Answering your question. I honestly don't have the particular point. The most vehicles I have ever dealt with (probably same to you) the oil gets up to the filling hole. But service manual for my 1945 Mack truck (tandem bogie though) prescribes to fill up to a level of one inch lower than the filling hole. There's a nuance that truck has wheel bearings separated from the banjo and they're greased don't get any oil from the differential. Your bearings get oil from the banjo I guess so I'd keep the level up to the edge of the hole. There could be an option to check if you remove one wheel hub and see the level in the banjo the oil starts leaking from the jack shaft tube to where the bearings are expected to be. That would be a required minimum to my understanding but seems easier to just fill up to the plug.

Hope this may help.

Vlad

On 5/4/2026 at 5:58 PM, james j neiweem said:

Did the H-65 look like the H-63? What was the difference/upgrade?

Do you like this?

Just go to the top of the page.

https://www.bigmacktrucks.com/collections/item/867-h65/?tab=comments#comment-194

And I doubt there are many (any?) chances to find a factory single axle R with air ride at the rear. B's are out of that point definitely. There were converstion made by owners though.

Just now, mowerman said:

Forgot to mention, they were all painted Allied van lines, colors, and all in really good shape like they had been restored

Bob, how did they look in Allied Van lines colors those days? Bright orange all over?

I like the look of them H's.

H-65 - a non-sleeper cab? Or am I wrong?

Thanks for the service Barry.

I hope we will survive after one more software update 

Happy B-day Joey!

Best wishes!!!

Yes, very clean job with clean welds. And as I noted multiple Mack trucks had tranny mounts made similar way from the factory. Hope you was able to count out desirable position of the engine well enough.

Did it suit? Looks like partially out

Congrats on the big step up!

47 minutes ago, Geoff Weeks said:

Yes, if you look at the drawing or if you have the cover off, you'll see when the main piston comes all the way up, a little "pin" that is adjustable, pushes on a little check ball and dumps the hyd pressure to the return so you don't have full hyd pressure on the steering that is "bottomed' against its stops. It is the same on the bottom cover. Once the box is on the truck and hooked up, you adjust those relief stops to dump pressure right before the box is hard against the end of travel.

You can see when it is apart which way it has to go on when going back with it so the pin is in the right position

I was always working by myself, so if I could avoid pulling the whole box, I did. I did do a couple box replacements by myself, and paid the price with my body doing so.

Thank you. I sure will put punch marks on everything I can. But always prefere to track down the correctness of assembly and further operation by understanding of principles. Takes long but pays back. You know what I mean and seems you know that better than me.

Just now, mowerman said:

And yes, it looks like my sector shaft can be removed with the box inside the frame. I think I just have to take out the alternator. But I won’t have to touch it now.

That's an interesting thought on the output shaft to be removed with the box in the chassis. Not almost sure but possibly. On the other hand my most trouble was removing the Pitman arm. Taking the box out wasn't easy task too but we were 3 men crue for that deal. Thanks for taking attention to my question Bob.

4 hours ago, Geoff Weeks said:

before removing the top cover mark its orientation to the main body, it has to go on so the relief adjusters will hit the relief ball when the box is turned to the end of its travel.  A coupla punch marks will help make sure it is on the correct way.

Well worthy advices. Thanks. I'm not almost sure on the initial correctness of the top cover fit. A portion of bolts were already loose and that bracket for U-joint intermedial shaft was partially hanging in a wind. Definitely its correct position wasn't clear to me. Somebody tried to fix the leak I guess, tried removing the cover and than something went out or order. Do I understand right I could figure orientation of the cover by position of the relief valve pin? It must point to the relief ball right? Also I'd like to investigate the condition of the Pitman arm shaft seal as I noted previousely.

Honestly for the best scenario I would like to disassemble the unit completely, cover mating surfaces with steel lazer cut covers, sandblast and paint the housings, regalvanize hardware than put everything back together with new OEM seals. But the irony is I have one more Mack power steering box which is supposed to pass along that described path and that's a plan for distant future. And that yellow DM is wanted to be movable in the nearest couple of months.

13 hours ago, Geoff Weeks said:

Many time I can replace the input shaft seal with the box in the truck and the output shaft connected to the steering.

That could be my way to go if I knew the design of the insides than. But those spare units put me onto wrong rails. Also DM has the box inside the frame so I haven't seen the whole thing until pulled it out.

So far my idea is to take the unit apart carefully and investigate the insides. Input shaft outside seals are needed definitely but seems they could be located just by the size. High pressure seal is another story. So seems I already have something more to put my hands on. 

Many thanks for the info support.

And it doesn't lock at a certain speed. It provides special torque distribution at any (?) speed.

Yes, about that. Interaxle diff full lock was an option. Interaxle power divider (which actually is an interaxle differential of unique Mack design) is a standard feature of all Mack tandem bogies starting from early 40's years. It doesn't lock up two drive axles completely but acts specially providing 3 times (or up to 3 times?) greater torque to the non-slipping at the moment axle. Common diff provides 50:50 torque distribution.

As long as you haven't found any switch with a tag of "interaxle lock - out" I suppose the truck doesn't have any. What is very common. To answer your question exactly you need to crawl under the chassis to observe the front portion of the diff housing of the front rear axle. In the area the prop shaft from the tranny comes to. There's a long housing to accomodate the pinion shaft. RR diff has it shorter since FR accomodate that power divider in it either and RR doesn't. So if the full air lock divider takes place you'd see a housing offset of the main housing with air line attached to it. If no of such and the pinion housing is simple cylindric shape that's standard Mack power divider (also called by people as automatic PD)

Just now, Vladislav said:

 Also a shaft with semi-round threads and circulating balls.

 

Upps, I'm wrong. No balls in the thread in Sheppard. Even much simplier design. Those balls are the most of headach assembling Benz boxes.

Also there's a bit of results of on-line search. Repair kit for 592 is represented by Automann (China or Turkey?) 465.4024 or (possibly) another option here: https://suntransmissions.com/products/complete-gear-seal-kit-transtec-rh-sheppard-592-series-3-4-5518091-8305?srsltid=AfmBOorts27v7nDsEdYNOaM7l9WNbOqG15ELRbp1TAigeXZKWd2O1K_U

Do those kits look as what could/should be put into 592?

19 hours ago, Geoff Weeks said:

Here, attached is the manual.

Sheppard-Manual-92-Series.pdf 2.5 MB · 1 download

Many thanks! Now I'm not blind!

In general this style of power steering gear is familiar to me. I rebuilt a few integral units for Mercedes cars and G-wagens. Also a shaft with semi-round threads and circulating balls.

Still not sure on rightness of identification of my box. I could locate the stamping today. There in the triangle near the adapter plate. 87H1540 and ST5 is written there. Also cast text can be read as 592S5-6 what may be count as 592-something. Does this guess seem correct?

21 hours ago, mowerman said:

Oh wait a minute,,,, are you asking if I have leftover parts???

Bob, no, no leftovers. I suppose you used all needed parts and I also suppose I will need the similar ones exactly. A question I'd ask regarding that haven't you saved the parts order or the invoice? I could use the seals ## from there and maybe a few other items.

Looks very similar. Could you locate any spairs for it? I just missed that part in your whole long story. Even tried to rifle through but ran outta time.

7 hours ago, other dog said:

"just a deterrent..." I don't believe that even for a second. My opinion is they would have been "testing" them on Israel at the first opportunity.

Or at least loudly say over the world they would.

I sure don't know for sure. I haven't seen any bombs there in person.