Warpman89 Posted January 15, 2010 Share Posted January 15, 2010 heys guys, i got an 88 r688 with what i believe to be mack rear ends. from what it looks like, there is a separate gear box on top of both carrier/differential housings, separate from the carrier housing. on the passenger side of these gear boxes, there is a 3/4" plug on a side cover, and when i opened them, no oil came out. also, on the front diff. where the driveshaft comes in there is another "box" that requires oil, and once again upon opening the plug, no oil came out...is this all normal or do i clearly need to add more oil? if this still doesnt make sense i will get pics...any help is appreciated Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/ Share on other sites More sharing options...
daveigou Posted January 15, 2010 Share Posted January 15, 2010 Hope this helps. The plugs at the power divider and top carries side cover are magnetic. They are only for initial fill and should be checked (for metal flakes) and cleaned at service. After that check oil level at the middle of the lower axle housing.DaveMack axle lube.doc Quote See my Flickr photostream page http://www.flickr.com/photos/96692978@N05/ Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-47439 Share on other sites More sharing options...
Warpman89 Posted January 16, 2010 Author Share Posted January 16, 2010 so are the power divider, bevel gear compartment, and differential housing all separate? they all have their own fill and drain plugs. the oil level in the differential is at the right amount, so am i ok, or do the power divider and bevel gear compartment need oil up to the fill plug too? Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-47444 Share on other sites More sharing options...
HK Trucking Posted January 16, 2010 Share Posted January 16, 2010 so are the power divider, bevel gear compartment, and differential housing all separate? they all have their own fill and drain plugs. the oil level in the differential is at the right amount, so am i ok, or do the power divider and bevel gear compartment need oil up to the fill plug too?As Dave said, the first time you fill the rear end after a drain or repair, you fill all 3 compartments, after that when servicing you just maintain the oil level in the bottom compartment up to the bottom of the hole where the plug screws in.On the back rear, just fill the upper & lower compartments initially, then maintain the level in the bottom compartment as described previously for the front .. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-47456 Share on other sites More sharing options...
LenRok Posted December 9, 2022 Share Posted December 9, 2022 (edited) So are the air bags supposed to be up or down when checking the rear bottom plug. As it makes about a 3L difference Edited December 9, 2022 by LenRok Typo Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517821 Share on other sites More sharing options...
Joey Mack Posted December 9, 2022 Share Posted December 9, 2022 (edited) Mack rears? Not much, but it is a good practice.. and you only check the rear plug for the level.. 5mm from bottom of the hole is the low level.. jojo Edited December 9, 2022 by Joey Mack more content needed Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517823 Share on other sites More sharing options...
MACKS Posted December 9, 2022 Share Posted December 9, 2022 2 hours ago, LenRok said: So are the air bags supposed to be up or down when checking the rear bottom plug. As it makes about a 3L difference The air bags have nothing to do with it,check the bottom plug hot,after a run.. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517827 Share on other sites More sharing options...
Popular Post mrsmackpaul Posted December 9, 2022 Popular Post Share Posted December 9, 2022 Because I don't and have never had a air ride back end in a truck I didn't think bags up or down would make a lot of difference I guess it might rotate the axle housing and this reads different However if I think about a normal spring suspension the oil is checked at ride height as thats all it ever is So to me even if it was airbag, common sense would tell me to check it at ride height as tgats were the axles are as you drive along But I dunno with this fangled air bag stuff Apparently they enhance ride or comfort or some such thing, but really, aren't we kust taking away the good things in this whole experience ? Paul 3 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517829 Share on other sites More sharing options...
LenRok Posted December 10, 2022 Share Posted December 10, 2022 8 hours ago, MACKS said: The air bags have nothing to do with it,check the bottom plug hot,after a run.. The air bags rotate the axle when filled. I had a guy do maintenance on the truck and he added oil while air bags were down. I checked the oil 2 days later while it was still in the shop but I aired up the truck first. When i pulled the plug almost 3litres came out. So i left it there as that's where the axle will be while the truck will be operating. Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517861 Share on other sites More sharing options...
LenRok Posted December 10, 2022 Share Posted December 10, 2022 8 hours ago, mrsmackpaul said: Because I don't and have never had a air ride back end in a truck I didn't think bags up or down would make a lot of difference I guess it might rotate the axle housing and this reads different However if I think about a normal spring suspension the oil is checked at ride height as thats all it ever is So to me even if it was airbag, common sense would tell me to check it at ride height as tgats were the axles are as you drive along But I dunno with this fangled air bag stuff Apparently they enhance ride or comfort or some such thing, but really, aren't we kust taking away the good things in this whole experience ? Paul Ha ha thanks for the info. Love the pic Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517862 Share on other sites More sharing options...
MACKS Posted December 10, 2022 Share Posted December 10, 2022 2 hours ago, LenRok said: The air bags rotate the axle when filled. I had a guy do maintenance on the truck and he added oil while air bags were down. I checked the oil 2 days later while it was still in the shop but I aired up the truck first. When i pulled the plug almost 3litres came out. So i left it there as that's where the axle will be while the truck will be operating. Ok yeah definitely check them when there level,also I was told to check them hot otherwise the top will leak down and give u a false reading.. Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517868 Share on other sites More sharing options...
Mark T Posted December 10, 2022 Share Posted December 10, 2022 13 hours ago, mrsmackpaul said: Because I don't and have never had a air ride back end in a truck I didn't think bags up or down would make a lot of difference I guess it might rotate the axle housing and this reads different However if I think about a normal spring suspension the oil is checked at ride height as thats all it ever is So to me even if it was airbag, common sense would tell me to check it at ride height as tgats were the axles are as you drive along But I dunno with this fangled air bag stuff Apparently they enhance ride or comfort or some such thing, but really, aren't we kust taking away the good things in this whole experience ? Paul That "suspension" must need torque rods or a rebushing. Lot's of side to side sway there. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517870 Share on other sites More sharing options...
mrsmackpaul Posted December 10, 2022 Share Posted December 10, 2022 I do believe that rebushing those style of bags is outside my scope of works, or at least the very "Minister For War and Finance" would have a serious frown upon her face But a few Bourbons and it probably wouldn't take a lot of effort for me expand into that field of works Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517913 Share on other sites More sharing options...
Joey Mack Posted December 10, 2022 Share Posted December 10, 2022 You have a HELL of a way with words, Paul... Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517915 Share on other sites More sharing options...
MACKS Posted December 10, 2022 Share Posted December 10, 2022 8 hours ago, Mark T said: That "suspension" must need torque rods or a rebushing. Lot's of side to side sway there. I would like to give them a through inspection before deciding to re bush them or not...😂 2 Quote Link to comment https://www.bigmacktrucks.com/topic/12229-mack-rears-upper-diff-oil-level/#findComment-517929 Share on other sites More sharing options...
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