Mack458 Posted March 12 Share Posted March 12 Hello all, I am in the process of replacing the powers steering hoses on my 1985 R Model Rescue Truck. When draining the system, the fluid appears to have been ATF. I was at my local Mack dealer in Pa. and asked what the proper fluid is for that unit. This truck is my hobby and spends most of its time indoors and really doesn't go out into the freezing temperatures. They thought it was 5-30 oil and that's the first time I have heard of that. Looking for recommendations from the experts here. Keep in mind that I have drained as much fluid as I can, so whatever is used might end up being a little mixed. As always, many thanks in advance, Mark Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/ Share on other sites More sharing options...
Joey Mack Posted March 12 Share Posted March 12 TRW system. ATF. Sheppard 15W40 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571170 Share on other sites More sharing options...
Mack458 Posted March 14 Author Share Posted March 14 Thanks Joey Mack 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571307 Share on other sites More sharing options...
Joey Mack Posted March 14 Share Posted March 14 🍻 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571308 Share on other sites More sharing options...
Joey Mack Posted March 14 Share Posted March 14 Im pretty sure hydra power boxes are 15 W40 too 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571309 Share on other sites More sharing options...
Popular Post JoeH Posted March 14 Popular Post Share Posted March 14 All the Mack's I've owned from 1974 to 2003 all want 15w40. PS pumps on all my trucks are mounted on the back of the air compressor or on the timing cover. If seals blow out on the PS pump you get PS fluid in your engine, so you should be running 15w40. 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571313 Share on other sites More sharing options...
mechohaulic Posted March 14 Share Posted March 14 back "a few years" when PS systems were separate having a belt driven pump with reservoir mounted on top which had a filter inside ; fluid of choice was ATF. later on 15-40 took over. as earlier post state . the 15-40 better idea. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571323 Share on other sites More sharing options...
Joey Mack Posted March 14 Share Posted March 14 My first question was if he had a belt driven steering pump. Even though its a Mack. Its a Mack ive never worked on. The filters inside those old pumps clog and make the steering harder.. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571324 Share on other sites More sharing options...
mowerman Posted March 14 Share Posted March 14 mine is belt driven im still not sure if im supposed to use oil or transmission fluid,,,,i put trans fluid in it first time but you guys said it uses motor oil 1966?????? Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571326 Share on other sites More sharing options...
mowerman Posted March 14 Share Posted March 14 Box is Sheppard pump is vickers Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571334 Share on other sites More sharing options...
mattb73lt Posted March 14 Share Posted March 14 I run a Sheppard box in one truck and a Garrison unit in the other. Both receive 15W40 and work fine. Somewhere in my Sheppard Instructions it does call for Engine Oil for a fluid. What ever I put in the crankcases goes in the reservoirs. Makes servicing easier as I only carry one oil for them. Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571335 Share on other sites More sharing options...
mowerman Posted March 14 Share Posted March 14 OK, thanks for that Matt but my concern was does that go as far as a 1966 model I don’t even know if it was an add-on but the Vickers pump looks relatively new although I bought the truck 30 years ago so it’s at least 30 years old Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571337 Share on other sites More sharing options...
mowerman Posted March 14 Share Posted March 14 I’ll be rebuilding the steering box soon I bought a rebuild kit in San Jose last summer that came with a sector bushing 200 bucks and I wanna make sure I got the right oil in it after I get it done Not even sure how I’m supposed to get the Pitman arm off. I’m sure I’ll have to borrow a puller somewhere. Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571338 Share on other sites More sharing options...
mechohaulic Posted March 15 Share Posted March 15 On 3/14/2025 at 10:40 AM, mowerman said: I’ll be rebuilding the steering box soon I bought a rebuild kit in San Jose last summer that came with a sector bushing 200 bucks and I wanna make sure I got the right oil in it after I get it done Not even sure how I’m supposed to get the Pitman arm off. I’m sure I’ll have to borrow a puller somewhere. belt driven "66 most likely came through with ATF; doesn't mean you can't change over to 15-40; only concern from this old man is whether or not the 15-40 may be too heavy for the filter slowing down the flow giving impression there's a PS problem?? far as the pitman arm removal ::: don't forget to back off/ remove the allen set screw(s) on back side of arm. a decent jaw puller will work along with slight tap on top/bottom of arm. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571426 Share on other sites More sharing options...
mechohaulic Posted March 15 Share Posted March 15 Just now, mechohaulic said: belt driven "66 most likely came through with ATF; doesn't mean you can't change over to 15-40; only concern from this old man is whether or not the 15-40 may be too heavy for the filter slowing down the flow giving impression there's a PS problem?? far as the pitman arm removal ::: don't forget to back off/ remove the allen set screw(s) on back side of arm. a decent jaw puller will work along with slight tap on top/bottom of arm. unofficially it has been done where the filter is removed from reservoir when changing over, new systems don't have filters anymore (like alot of cutbacks) . still have a sealed system; one less item to relace on PM's 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571427 Share on other sites More sharing options...
mowerman Posted March 15 Share Posted March 15 ok thanks for that,,yes i loosened that screw a long time ago and i keep shooting wd40 around the teeeth every time i think of it 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571429 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 11 minutes ago, mechohaulic said: belt driven "66 most likely came through with ATF; doesn't mean you can't change over to 15-40; only concern from this old man is whether or not the 15-40 may be too heavy for the filter slowing down the flow giving impression there's a PS problem?? far as the pitman arm removal ::: don't forget to back off/ remove the allen set screw(s) on back side of arm. a decent jaw puller will work along with slight tap on top/bottom of arm. I have never seen a older Sheppard box that anything other than engine oil has been called for in the spec's. If you have documentation of ATF being used in Sheppard boxes, I'd like to see it. 66 would likely have the old 2 digit boxes "29, 39" etc and these were "low pressure" boxes. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571433 Share on other sites More sharing options...
mechohaulic Posted March 15 Share Posted March 15 in cases where the pitman don't remove too easy even having the puller on it; sit-in cab and work steering wheel back and forth ::: engine off of course. it's been known to be helpful ;; the twisting motion . better then beating the arm with a hammer. total removal of the set screw (it's a long bast- - -d) is better so it;s not in the way of puller jaws. a good bearing puller installed first behind the arm will give more area for jaw puller. never know it may slide off. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571434 Share on other sites More sharing options...
mechohaulic Posted March 15 Share Posted March 15 1 minute ago, Geoff Weeks said: I have never seen a older Sheppard box that anything other than engine oil has been called for in the spec's. If you have documentation of ATF being used in Sheppard boxes, I'd like to see it. 66 would likely have the old 2 digit boxes "29, 39" etc and these were "low pressure" boxes. only documentation available is from the "book" called old school. sorry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571435 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 Right from the Manual Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571439 Share on other sites More sharing options...
mowerman Posted March 15 Share Posted March 15 thanks for that,,,,bob Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571441 Share on other sites More sharing options...
mechohaulic Posted March 15 Share Posted March 15 at this point since I don't own one; so be it. however I don't see in the book where it states 15/ 40 only10//40 which in the day before all the synthetic was closer to hyd oil which comes closer to ATF , ALSO no where on the page is it stating ALSO change the PS filter ;possibly indicating by then 10/40 was standard leaving those few old people stuck in their ways of using ATF. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571442 Share on other sites More sharing options...
mowerman Posted March 15 Share Posted March 15 and thanks for all the responces,,,i think mine ended in 29,,,,,it might say it on the rebuild kit bob Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571443 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 2 hours ago, mechohaulic said: at this point since I don't own one; so be it. however I don't see in the book where it states 15/ 40 only10//40 which in the day before all the synthetic was closer to hyd oil which comes closer to ATF , ALSO no where on the page is it stating ALSO change the PS filter ;possibly indicating by then 10/40 was standard leaving those few old people stuck in their ways of using ATF. Sheppard only supplied the steering gear, the OEM would supply the res, pump line etc, so not called out in their manual for the gear. It says "wrong oil" as a problem and list the right oil, don't know what more you expect them to say. ANY oil will work after a fashion, but using what the mfg designed it for will give best results. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571456 Share on other sites More sharing options...
Geoff Weeks Posted March 15 Share Posted March 15 Found a screen shot of the lube requirements page. This is for the two digit and 3 digit boxes for the time period we are talking about. Later (M100) series may be different. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75275-1985-r-model-proper-power-steering-fluid-question/#findComment-571457 Share on other sites More sharing options...
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