Fastduramax

I finally started my hub pilot conversion, kind of had to as you will see in the pics lol... Anyway a few questions for anyone who has done it as I cant seem to get a concrete answer around here... My spoke hubs had the bearing spacers or washers that slide over the spindle and rest between the spindle shoulder and inner bearing, I was told both to use the spacer and not to use it UGH ! Here are my concerns, check out the pic there is clearly a huge difference in the offset of the bogeys, but will obviously equal out when I'm done, second, I wasn't overly thrilled with the short distance my Voyager seal slid onto the spindle shoulder but that said I've run the piss out of her for 2 days now and no leaking seal... Anyone who's been here please chime in ! I'll post the pics....

JOJO !!! Kmon my friend is any amount of HP ever really "enough" !!! Kinda like "to much HP" That phrase is totally off the charts !

Upon much research I have come down to these 2 hub numbers, HR605K obsolete new (non ABS) And the new number HR819K can someone confirm if these are the correct hubs for my truck... 88 RD 688S 18 front, maybe 20 I never figured out how to distinguish an 18 from a 20... Thanks !

Thanks guys and thanks for the thumbs up Mackone... She's a good ole puppy she works daily in the summer and parked in the winter and gets well loved... Just dropped $4800 clams into the rear suspension jeeeesh !

Have to agree with OldRed I just did mine and gained that 3" right back (44 rears) That said I have had 3 Camelback Macks and have never seen the springs "sag" I have had a broken pack leaf but never a sag.... I have had my 88 for 15 years and never changed a rear spring and are believed to be the original springs believe it or not ! Anyway if your insulators are shot again try this... Atro urethane bottoms and OEM rubber tops, urethane rides harsher but lasts 3X longer and using the rubber tops takes the shock out if your ride and wheel hop in certain situations and the tops support no weight.... Proven combination in my experience...

Thanks guys both good ideas and I did cut a piece of black commercial grade black carpet a while back and it currently ain't too pretty... Problem with the upholstery shop thing is my rubber floor does not make a good stencil anymore and a new one is very pricy if you have priced one lately... The beauty of the "kit", I bought one from Mack like 20 years ago lol, the carpet is fully bound and you get the nice piece for the firewall, just my OCD....

Search the Stengel Bros website, they have a company that makes super nice complete kits, not sure for DM but the list was long last I looked I'll be doing my RD this summer....

Not certain but pretty sure, no audible leaks and they get changed quite often because I cant seem to get a compressor from Mack (3rd) that does not push oil through the system....

Thanks Joe It is letting off the brake pedal giving me the problem with the delay issue, FYI the QR valves made NO difference so my problem is obviously further upstream ugh ! I have a treadle valve in stock because mine developed a tendency to "feedback" air especially when it's cold out, not sure to start there, bit of a pain in the ass to change especially if unnecessary or try to figure out if its a faulty relay ? Also found what I think is a relay on a crossmember on the driver side just above the 12 speed, noticed it while changing the 12 speed splitter relay valves... That required some extremely foul language, like 9 1/4" airlines to 2 tiny valves and all brass union fittings and zero room to work ugh !

Still looking for a full RD carpet kit, I assume Superliner would work also, I throw this out there once a year or so with no luck lol !

Still looking for a full RD carpet kit, I assume Superliner would work also, I throw this out there once a year or so with no luck lol !

Thanks Joey

Hey Mackone let me know what you got new or reman and from who and most importantly if it pushes oil through your system, I'm on my third compressor right from Mack and it pushes oil like a Saudi oil field ugh !!! I gave up, I just chase down each valve and maxi can the oil ruins... Ironically just today replaced my heater/AC control panel and both piston accuators the oil has ruined !

Hub pilot ?

My 88 RD688S had no QRV on either rear axle, strange my 88 from years ago had them go figure ? Anyway I was getting an annoying slow release issue lately so I ordered 2 assuming it was a QRV issue to discover I didn't have any lol ! Well I installed them anyway thinking it can't hurt, I ran them to the service side airline of my maxi cans can someone tell me is this is correct ? Thanks, Todd.

Thank you MT you are obviously a very educated man and that was an explanation I was looking for, well sort of lol... And yes I will buy my man Billy breakfast if I get to see him again he's to grumpy to hate on... Guess I will crank up the Bluetooth and drive it like I stole it and hope for the best... If I may I'd like to run this by you, the 12 I pulled out had the upper right counter shaft push out through the cover plate (357K original miles) quietest and best shifting 12 I have ever had unfortunately I happen to be the third owner so I wasn't the pilot its entire life... Anyway I would like to oversee a complete rebuild of my original tranny for insurance on my very vocal one, I got a price on a complete Timken bearing kit for under $900 clams my local Mack dealer said $1500+ if that sounds correct... In your opinion is it worth the investment for the future ? Also as a side note I have a good Mack rear mount PTO on the shelf that I know is getting near impossible to find these days.

Ok thanks guys, yes Paul it does go away while rolling and even under Dynatard but screams under throttle even light throttle... I did a quick inspection of the tranny before installing it because it sat for so long the only concern I saw was a fairly sharp gear under the drivers side PTO cover not sure if that could be the culprit or not ? I do know it got a full bearing kit when it was rebuilt...

FJH even if I was running a side mount it shouldn't scream when not engaged correct ?

Nope rear mount PTO, I hate side mounts in a Mack I spread dump a lot and having to have the main in gear is a pain in the ass even though I can do it....

Thanks Paul, could you explain further ?

Welp a good 20 hours plus of labor my rebuilt 12spd is in... Take it for a rip and its deafening in 10th and 12th gears under throttle in other words 4th and 5th hi, quiet in direct... Totally screwed because I bought this tranny 8 years ago for my previous RD that turned out to have a bad rear end so I kept this tranny for a backup confident that it was built by a life long highly regarded Mack technician that has since retired... Anyone have any input on the cause ? This is like the 5th 12spd I have owned and have to say none were ever quiet and none shift the same but this one is scary obnoxious ! Drive it till it grenades ? Not sure if it will last 1 load ,1 week, 1 month, 1 year or if it will just sing like Axle Rose forever !

Ok here is the skinny for those who may run into my dilemma... As Truckster said old style versus new style... From my research yes the spring loaded clutch brake saves on wear and tear but when the springs break with nothing else wrong its a 16 to 20 hour job to pull a 12spd out of a tri-axle to fix not good ! I unbolted the spring loaded housing from my rebuilt tranny and bolted on the solid casting from my smoked tranny and good to go just replace the existing seal... One other thing to check is to make sure you have a splined countershaft if you plan on running a rear mount PTO don't get the new tranny in and find out after the fact or you're looking at another $1800 plus for a side mount PTO and they SUCK in a Mack tranny ! Anyway all good in the Peru hood should be dumping dirt by Monday...

Thank you Truckster I believe (praying) you are correct as most of the feedback I am getting around here says the same... Just hoping the clutch fork, throw out bearing and clutch brake ect are all the same spec old style and new style !

I agree Fuel unfortunately I don't have access to either tranny until tomorrow... UGH !