macattack Posted May 5, 2012 Share Posted May 5, 2012 been slowly tracking down a wobble issue i have with my mack. another member mentioned the peanuts in my rears. this is what i began to notice. at around 35-40 mph i get a wobble that feels like a flat tire or a bulge in a tire. if i hold it for a few seconds during the first sign of the wobble and then increase my speed the wobble is not as noticeable, but if i try to fly thru the wobble at a fast speed the wobble gets worse. now does my next statement make any sense. feels like maybe the those peanut thingys or whatever are try to balance themselves or catch up to speed.the truck is a mr688s with an allison 740rs auto trans and mack rears. one note i am getting my front springs replaced early next week. i will post my results.thanks Quote Link to comment Share on other sites More sharing options...
220cummins Posted May 5, 2012 Share Posted May 5, 2012 "peanuts" are little balls in the power divider. When your rear drive slips it automatically locks to have power to both axles. Instead of having an air toggle to lock in the power divider it automatically does so.. It has nothing to do with wobble. It's inside your power divider on the intermediate axle. Quote Link to comment Share on other sites More sharing options...
macattack Posted May 5, 2012 Author Share Posted May 5, 2012 thanks for the info. can a guy remove a plate to inspect or clean these things? Quote Link to comment Share on other sites More sharing options...
vision386 Posted May 5, 2012 Share Posted May 5, 2012 Damn, did i mis-interpret this post! i was scared Jimmy Carter had managed to get back in the picture!........................Mark Quote Mack Truck literate. Computer illiterate. Link to comment Share on other sites More sharing options...
Rob Posted May 5, 2012 Share Posted May 5, 2012 thanks for the info. can a guy remove a plate to inspect or clean these things?They run in gear oil and do not get dirty or sticky require cleaning. If you drop the driveshaft and pull the front drive yoke on the front rear, then pull the cover they are in there. These are called "plungers", and the cam operates against them forcing them into the "cage". These parts wear and are not servicable. They are also not really inexpensive to replace either.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
Rob Posted May 5, 2012 Share Posted May 5, 2012 Damn, did i mis-interpret this post! i was scared Jimmy Carter had managed to get back in the picture!........................MarkI still have my unopened can of "Billy Beer" to!!Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
theakerstwo Posted May 5, 2012 Share Posted May 5, 2012 I just spent 5 min typing a mess about the wobble and lost it. maybe later. Quote glenn akers Link to comment Share on other sites More sharing options...
Rob Posted May 5, 2012 Share Posted May 5, 2012 I just spent 5 min typing a mess about the wobble and lost it. maybe later.Don't that just piss you off? Man it has happened to me several times.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
theakerstwo Posted May 5, 2012 Share Posted May 5, 2012 I will try it again now that i got some time but talking about the wobble. I have had it in my 89 mack ever time the rear tires get worn down below trhe front tires. I hav seen this same problem off and on with a few trucks for 40 or 50 years. It is a wobble feel but what i have proved to my self is its the cam and dogs or peanuts worn down enough that when the tires are not trhe same size the dogs try to hang the cam to the outer hub causing a interment surce or power flow.Hope that makes sense but new tires or getting the tires with in a 1" from large to smallest size in tireswill stop it.I have always said 3/4" all the way around because years ago that was what the ser manual said.If the size is too far off on the tires from largest to smallest the power divider will pop.On the truck here being talked about look and see if it has a air lock in and if it does lock it in and run down the road and see if it stops the wobble. Even tho it is air lock up it still has the peanut and cam hub like the one with out air cyl lock up. glenn Quote glenn akers Link to comment Share on other sites More sharing options...
Mike Posted May 6, 2012 Share Posted May 6, 2012 Damn, did i mis-interpret this post! i was scared Jimmy Carter had managed to get back in the picture!........................MarkExactly what I was also thinkin, Mark. Scary knowing we are in a race to see how quickly the country can destroy itself. We are still supporting his salary.mike Quote Link to comment Share on other sites More sharing options...
hatcity Posted May 6, 2012 Share Posted May 6, 2012 And here I just sent the Mrs. to get 7 jars of Skippy (large).Peanutgeddon? Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment Share on other sites More sharing options...
b61mack Posted May 6, 2012 Share Posted May 6, 2012 thanks for the info. can a guy remove a plate to inspect or clean these things? it doesent hurt to clean the magnet in the bottom of the power divider and refill with gear oil. Ron 1 Quote Link to comment Share on other sites More sharing options...
Timothy B Demarco Posted May 6, 2012 Share Posted May 6, 2012 Depending on your front steer tires, jack up front end and check to see if any of your steer tires are out of round. Just put a small sledge hammer beside and in the front of the wheel and check the runout. Quote Link to comment Share on other sites More sharing options...
macattack Posted May 6, 2012 Author Share Posted May 6, 2012 Depending on your front steer tires, jack up front end and check to see if any of your steer tires are out of round. Just put a small sledge hammer beside and in the front of the wheel and check the runout.my fronts are 425 65r 22 and about a year old, but i will check that. thanks Quote Link to comment Share on other sites More sharing options...
Timothy B Demarco Posted May 13, 2012 Share Posted May 13, 2012 I deal with alot of 425 tires. They can be tricky. Try putting 14 oz of counter balancing beads in the tire if you can. I had a truck I just 425's on and two weeks later the driver he has a bad wobble in the front. The first thing I did was check the runout and sure enough, the tire had bulge on the inside and after i replaced it no more wobble. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.