cfd511 Posted March 25, 2022 Share Posted March 25, 2022 Have a 2002 mack 688 . When i load the truck and im driving im getting a noise / and a feeling like the transmission gear is skipping . Its hard to explain but it feels like a gear is trying to engage enen though im not hottibg the splicer . The truck runs great and was haul heavy loads up hills with no slipping . Any ideas Quote Link to comment Share on other sites More sharing options...
cfd511 Posted March 25, 2022 Author Share Posted March 25, 2022 Here is a video of the noise IMG_3178.MOV Quote Link to comment Share on other sites More sharing options...
mrsmackpaul Posted March 25, 2022 Share Posted March 25, 2022 Video wont play I am assuming you have a transmission with some air shift, as in forward reverse, high and low However it sounds like your loosing air pressure or theres crap in your gears no allowing them to slide fully in I would change the transmission air filter first Then if the problem is still there, check for air pressure on the gear box should be about 60 psi, anywhere from 45 to 75 is fine Then drop the transmission out and lift it apart for a look-see Or get us some more details on the transmission model, theres a few Maxitorque types Paul Quote Link to comment Share on other sites More sharing options...
63BMack Posted March 25, 2022 Share Posted March 25, 2022 Peanuts in the Power divider wore out??? 1 Quote Link to comment Share on other sites More sharing options...
Steve L Posted March 25, 2022 Share Posted March 25, 2022 I’ll put my money on the peanuts. Done plenty of them over the years. 1 Quote Link to comment Share on other sites More sharing options...
Steve L Posted March 25, 2022 Share Posted March 25, 2022 Also if it’s making that much noise the inner and outer cams may need replacing. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 25, 2022 Share Posted March 25, 2022 Those damn peanut's.... they can fool you into thinking its tranny noise. the drive shaft is a tube, and carries the noise up to the tranny... jojo 1 Quote Link to comment Share on other sites More sharing options...
terry Posted March 25, 2022 Share Posted March 25, 2022 Yeah I know a guy that had a driveline noise, pulled the tranny had it rebuilt, put it back together, and yes noise still there, noise was front rear end, talk about a unhappy camper! Terry 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 25, 2022 Share Posted March 25, 2022 no doubt... Quote Link to comment Share on other sites More sharing options...
85snowdog Posted March 25, 2022 Share Posted March 25, 2022 (edited) There was a thread on here a loooong time ago about a fella that had clunking noises coming through the drive train, It turned out he had put new tires on one axle only and the mis matched tires were causing a problem with the power divider . I don't think this is the case , just throwing it out there . Edited March 25, 2022 by 85snowdog spelling Quote Keith Link to comment Share on other sites More sharing options...
Popular Post fjh Posted March 25, 2022 Popular Post Share Posted March 25, 2022 6 hours ago, 63BMack said: Peanuts in the Power divider wore out??? to confirm this theory if there is a power dIvider lock use it! If the noise goes away you nailed the problem! 3 Quote Link to comment Share on other sites More sharing options...
fjh Posted March 25, 2022 Share Posted March 25, 2022 1 minute ago, 85snowdog said: There was a thread on here a loooong time ago about a fella that had clunking noises coming through the drive train, It turned out he had put new tires on one axle only and the mis matched tires were causing a problem with the power divider . I don't think this is the case , just throwing it out there . as stated Tire size plays a huge part! 1 Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted March 25, 2022 Share Posted March 25, 2022 (edited) More then 1/2in difference in tire size is a huge no no on macks. Says so in the service manual. Edited March 25, 2022 by Onyx610 Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted March 25, 2022 Share Posted March 25, 2022 Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted March 25, 2022 Share Posted March 25, 2022 Quote Link to comment Share on other sites More sharing options...
Popular Post theakerstwo Posted March 25, 2022 Popular Post Share Posted March 25, 2022 1 hour ago, fjh said: as stated Tire size plays a huge part! Years ago i installed a 4 speed aux trans behind a 6 speed for lower gears for a house mover.We did the ujoint angles like should be but a few days later he came in with a noise.His buddy say they did not install trans right.I sent him on his way but a month later the story comes out were he had taken it to another shop and had some more work done to it but no fix.He comes in having a fit over it and take it with him and drive some more and found the peanut knok.I looks at his tires and one is flat and its mate is low.I say go fit tires and get back.I never saw truck again.I have always said on a mack rear end 3/4" difference in tires is max. 2 1 Quote glenn akers Link to comment Share on other sites More sharing options...
fjh Posted March 25, 2022 Share Posted March 25, 2022 (edited) 22 minutes ago, theakerstwo said: Years ago i installed a 4 speed aux trans behind a 6 speed for lower gears for a house mover.We did the ujoint angles like should be but a few days later he came in with a noise.His buddy say they did not install trans right.I sent him on his way but a month later the story comes out were he had taken it to another shop and had some more work done to it but no fix.He comes in having a fit over it and take it with him and drive some more and found the peanut knok.I looks at his tires and one is flat and its mate is low.I say go fit tires and get back.I never saw truck again.I have always said on a mack rear end 3/4" difference in tires is max. yup First thing to look for if your running Mack rears! my belief is if you got to run miss match tires ( Don't recommend it how ever ) Run em kitty corner that spreads Some of the wear thru out the diffs and power divider! Just an opinion Edited March 25, 2022 by fjh 2 Quote Link to comment Share on other sites More sharing options...
Glensts Posted March 26, 2022 Share Posted March 26, 2022 I had same issue, put in power divider and it went away. worn peanuts. Quote Link to comment Share on other sites More sharing options...
cfd511 Posted March 26, 2022 Author Share Posted March 26, 2022 thanks for all the responses. the tires are all brand new and same size. going to try locking rears and see if noise goes away. will also check peanuts Quote Link to comment Share on other sites More sharing options...
cfd511 Posted March 26, 2022 Author Share Posted March 26, 2022 can the peanuts be changed easily. I’m not familiar with such. Quote Link to comment Share on other sites More sharing options...
Vladislav Posted March 26, 2022 Share Posted March 26, 2022 Yup. All the setup is in the front housing of the FR axle diff. Take away the prop shaft, drive yoke, front cover and you'll able to pull a cage out and see them wedges. Sure better to look at a cut or blow out view in a book and read a bit. The CRD92/93 maintenance manual may be found on the net. Vlad Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment Share on other sites More sharing options...
Steve L Posted March 30, 2022 Share Posted March 30, 2022 Be sure to check the cams while apart. If the peanuts are worn ( I have seen them chipped ) most likely the cams are worn also. The inner cam comes out with the assembly so easy to inspect but you need to look inside the carrier nose to inspect the outer cam. Replacing only the peanuts when the cams are worn only limits the new peanuts life. I have heard of the peanuts and inner cam being replaced successfully due to the drama/ complications of removing and pre loading the piñion bearing, not something I would do unless pressed by a customer. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 30, 2022 Share Posted March 30, 2022 replacing the outer cam requires the removal of the input/ bevel pinion housing. Pay attention to the shim pack thickness for the housing, and the shim for the outer cam. if you attempt this, you will need to make a jig that holds the outer cam in place so it cant rotate, and it will be bolted to the housing as well. then the big nut inside is torqued to around 1300 lbft. if you get this apart, decide on bearing condition. then when you put it back together, you have to press the outer cam in place, as a completed assembly. the pressure is 10,000 PSI.. wrap a string around the housing several times, and pull the string and pull the string with a 'fish scale' from youre tackle box. reused bearing pull at 2-5 llbs, new bearing pulls at 3-6 lbs. this will indicate proper bearing preload. adjust the shim thickness as needed.. once that is done then you need to torque that skinny nut to around 1300lbft. once done then you put the assembly into the carrier housing with 2 bolts holding it in place, and check the tooth pattern for the bevel pinion and the bevel gear, use Prussian blue gel to set the 'root' good, adjust the pattern using the thin shims for the input housing. it is highly possible that the original shim pack will be correct. if so, put her together.. good luck to you, jojo 2 Quote Link to comment Share on other sites More sharing options...
terry Posted March 30, 2022 Share Posted March 30, 2022 23 minutes ago, Joey Mack said: replacing the outer cam requires the removal of the input/ bevel pinion housing. Pay attention to the shim pack thickness for the housing, and the shim for the outer cam. if you attempt this, you will need to make a jig that holds the outer cam in place so it cant rotate, and it will be bolted to the housing as well. then the big nut inside is torqued to around 1300 lbft. if you get this apart, decide on bearing condition. then when you put it back together, you have to press the outer cam in place, as a completed assembly. the pressure is 10,000 PSI.. wrap a string around the housing several times, and pull the string and pull the string with a 'fish scale' from youre tackle box. reused bearing pull at 2-5 llbs, new bearing pulls at 3-6 lbs. this will indicate proper bearing preload. adjust the shim thickness as needed.. once that is done then you need to torque that skinny nut to around 1300lbft. once done then you put the assembly into the carrier housing with 2 bolts holding it in place, and check the tooth pattern for the bevel pinion and the bevel gear, use Prussian blue gel to set the 'root' good, adjust the pattern using the thin shims for the input housing. it is highly possible that the original shim pack will be correct. if so, put her together.. good luck to you, jojo Quite the procedure! terry Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted March 30, 2022 Share Posted March 30, 2022 (edited) yes Terry, it is.. of course it could just be torn down and stuck back together, but how long will it live? I posted that info so he could see what is involved before he takes it apart.. hope to see more comments for him,, jojo Edited March 30, 2022 by Joey Mack More content needed 1 Quote Link to comment Share on other sites More sharing options...
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