Rear End Snap/bang, What Is My Problem?

[allfritz123]

I hope someone can help me. I have a 1999 E7-460 with a T2180, 18 speed double over and Mack 44,000 model S440 rear ends ratio 4.73. I have 400,000 miles on it. I bought the truck several years ago and I changed the rear end oil to 80W90 synthetic when I took it home. (Should I have added an additive?) I may have put on 15,000 miles all gravel roads for the most part.

I used to get an occasional snap/bang when I cornered with a load, not that often. If I cornered slowly I generally could avoid this. I had assumed that maybe it was the load shifting on the 5th wheel platter so never really gave it much thought.

Yesterday I loaded the truck up (tridem grain trailer) and it is now banging more and not on corners but when I shift and step on accelerator a little too hard. I drove it about 15 miles back to my home base and I noticed if I stepped on it, at times I could get a snap out of it. I checked temperatures manually and my rear ends are warm but not hot (seem normal). I have no oil leaks and an air ride suspension. I tried backing with it in the yard with the load and I can see the driveshaft between the two rear ends through my rear window (no sleeper). It looks like it gets to a spot and almost has a deadspot as if there is a tooth missing? I haven't marked it yet but I was going to see if it is consistent with one rotation of the driveshaft and that seems to coincide with the snap I hear.

Which rear end goes first the rear rear?

I have never had a mack rear end apart so I don't even know what they look like or what can go wrong. I assume there is a pinion gear at the end of the driveshaft. Could a cog go out? Will it hurt to run it like this for a day? I have several loads to make before I can get to fixing it. It only makes the banging noise when I shift or step on the accelerator a little hard. I don't notice any problems when I am rolling down the road, no unusual noises.

Any help would be much appreciated.

Kind Regards,

Allan in Saskatchewan, Canada

[Deuce118]

check your torque arms.

[HK Trucking]

I hope someone can help me. I have a 1999 E7-460 with a T2180, 18 speed double over and Mack 44,000 model S440 rear ends ratio 4.73. I have 400,000 miles on it. I bought the truck several years ago and I changed the rear end oil to 80W90 synthetic when I took it home. (Should I have added an additive?) I may have put on 15,000 miles all gravel roads for the most part.

I used to get an occasional snap/bang when I cornered with a load, not that often. If I cornered slowly I generally could avoid this. I had assumed that maybe it was the load shifting on the 5th wheel platter so never really gave it much thought.

Yesterday I loaded the truck up (tridem grain trailer) and it is now banging more and not on corners but when I shift and step on accelerator a little too hard. I drove it about 15 miles back to my home base and I noticed if I stepped on it, at times I could get a snap out of it. I checked temperatures manually and my rear ends are warm but not hot (seem normal). I have no oil leaks and an air ride suspension. I tried backing with it in the yard with the load and I can see the driveshaft between the two rear ends through my rear window (no sleeper). It looks like it gets to a spot and almost has a deadspot as if there is a tooth missing? I haven't marked it yet but I was going to see if it is consistent with one rotation of the driveshaft and that seems to coincide with the snap I hear.

Which rear end goes first the rear rear?

I have never had a mack rear end apart so I don't even know what they look like or what can go wrong. I assume there is a pinion gear at the end of the driveshaft. Could a cog go out? Will it hurt to run it like this for a day? I have several loads to make before I can get to fixing it. It only makes the banging noise when I shift or step on the accelerator a little hard. I don't notice any problems when I am rolling down the road, no unusual noises.

Any help would be much appreciated.

Kind Regards,

Allan in Saskatchewan, Canada

Sounds to me like the power divider cams & wedges are worn to the point that they are jumping over on a hard pull, or, you've got a mismatch in tire diameters from the front drive axle to the rear drive axle.

This has been discussed quite a few times previously on here, I'll see if I can find some of the threads & I'll post links to them

[HK Trucking]

http://www.bigmacktrucks.com/index.php?showtopic=12154

http://www.bigmacktrucks.com/index.php?showtopic=12992

[theakerstwo]

Make sure all drive tires are same height.

[b61mack]

I hope someone can help me. I have a 1999 E7-460 with a T2180, 18 speed double over and Mack 44,000 model S440 rear ends ratio 4.73. I have 400,000 miles on it. I bought the truck several years ago and I changed the rear end oil to 80W90 synthetic when I took it home. (Should I have added an additive?) I may have put on 15,000 miles all gravel roads for the most part.

I used to get an occasional snap/bang when I cornered with a load, not that often. If I cornered slowly I generally could avoid this. I had assumed that maybe it was the load shifting on the 5th wheel platter so never really gave it much thought.

Yesterday I loaded the truck up (tridem grain trailer) and it is now banging more and not on corners but when I shift and step on accelerator a little too hard. I drove it about 15 miles back to my home base and I noticed if I stepped on it, at times I could get a snap out of it. I checked temperatures manually and my rear ends are warm but not hot (seem normal). I have no oil leaks and an air ride suspension. I tried backing with it in the yard with the load and I can see the driveshaft between the two rear ends through my rear window (no sleeper). It looks like it gets to a spot and almost has a deadspot as if there is a tooth missing? I haven't marked it yet but I was going to see if it is consistent with one rotation of the driveshaft and that seems to coincide with the snap I hear.

Which rear end goes first the rear rear?

I have never had a mack rear end apart so I don't even know what they look like or what can go wrong. I assume there is a pinion gear at the end of the driveshaft. Could a cog go out? Will it hurt to run it like this for a day? I have several loads to make before I can get to fixing it. It only makes the banging noise when I shift or step on the accelerator a little hard. I don't notice any problems when I am rolling down the road, no unusual noises.

Any help would be much appreciated.

Kind Regards,

Allan in Saskatchewan, Canada

If you have a power divider lock you might try engageing it going straight and see if it still dose it,might tell you if the cam and peanuts are woreout. Ron

[Road Hog]

It sounds as if the interaxle differential may be making the noise-it can be caused by numerous things-make sure all tire are the same size and properly inflated-if everything at the wheels is good, the interaxle buttons or cams oould be worn which csn cause the driveshaft to slip almost a gear slipping-if that is the problem the noise will almost be a ringing sound (resonating through the driveshaft-it also could be a broken spider gear in one of the rears but that usually only will make a noise when cornering or if one of the wheels are spining-the easier check is the interaxle differential which if it is a Mack rear, is right in the front section of the front rear-

[fifth wheel]

Had the same symptoms a few years back, broken pinion tooth front carrier (crd 92) Haven't tried one but I bet you use a fiber optics scope through the fill plug to look in the pinion housing.

FW

[Bollweevil]

As you are searching for this malfunction, if the truck has a front drive shaft with a mid shaft bearing. check the yoke at the bearing. It is splined to the shaft and retained by a center bolt. I once had a pop and crack like you describe, that I just could not find. I replaced a worn front diff, and went through the rear with no joy. Just a few days later I had to walk home. The front drive shaft turned fine, the rear wouldn't. Needless to say, it also sounded like a hog eating hickory nuts

[allfritz123]

As you are searching for this malfunction, if the truck has a front drive shaft with a mid shaft bearing. check the yoke at the bearing. It is splined to the shaft and retained by a center bolt. I once had a pop and crack like you describe, that I just could not find. I replaced a worn front diff, and went through the rear with no joy. Just a few days later I had to walk home. The front drive shaft turned fine, the rear wouldn't. Needless to say, it also sounded like a hog eating hickory nuts

Thanks for everyone's help in diagnosing this problem. I do have a mid shaft bearing. Looks like the first thing I should check but don't quite follow. Are the splines worn off the yoke and that caused this problem? Do you mean large nut on the yoke (don't quite follow center bolt description). Most yokes are held on by a large nut. Sorry I am a little bit noobish on this and away from the truck til tomorrow morning.

Also Is my carrier the crd92 fifth wheel? I do have a rigid camera I could look inside the pinion housing. I assume I would find a broken tooth there if that is the problem. for all the rest, I haven't changed any tires since I got the truck. Definite possibility it could be worn peanuts and cam but very unfamiliar with these Mack carriers. I sure wished I could get my hands on a parts diagram for a rear end so I would be able to better understand the system. If anyone has a pdf I sure would appreciate it. My e-mail is aafritzke@sasktel.net.

I did check the torque arms I believe. If those are the arms that tie from the center of the carrier to the frame. They look normal, rubbers in place. All crosses looked good. no oil leaks anywhere.

Regards to all and thanks for the many responses!!

Allan

[allfritz123]

If you have a power divider lock you might try engageing it going straight and see if it still dose it,might tell you if the cam and peanuts are woreout. Ron

I am going to check this out too - looks like this link is a great help after getting the results of the above test!

http://www.bigmacktrucks.com/index.php?showtopic=12973

Edited November 1, 2010 by allfritz123

[QCDriver]

I had same sound last year, checked and greased driveline, 2k started all over,and kept on greasing.

Well on day the u-joint exposed itself. Needles gone in 1 cap.

[allfritz123]

I had same sound last year, checked and greased driveline, 2k started all over,and kept on greasing.

Well on day the u-joint exposed itself. Needles gone in 1 cap.

I did try the truck with power divider locked and I have no snapping. So I assume that my peanuts and cam is gone. Are these items located in the power divider housing? I slowly moved truck in the shop and moved it until I could find the snapping spot. Seems to be one spot and appears to come from power divider?

I drained the oil out of power divider and both the filler and drain plug are covered with fine pieces of iron filings. No big pieces - just lots of litle metal junk. Nothing to look at inside the drain or filler plug. I pulled the cross off at the front rear end. Drive train looks good from there to front.

I have a CRD 203. If peanuts and cam are in the power divider, can I remove this section in order to replace or do I have to remove the whole CRD 203 from the carrier? Are they located in the first section with the air actuator?

Thanks for everyones help and input!

Allan

[b61mack]

I did try the truck with power divider locked and I have no snapping. So I assume that my peanuts and cam is gone. Are these items located in the power divider housing? I slowly moved truck in the shop and moved it until I could find the snapping spot. Seems to be one spot and appears to come from power divider?

I drained the oil out of power divider and both the filler and drain plug are covered with fine pieces of iron filings. No big pieces - just lots of litle metal junk. Nothing to look at inside the drain or filler plug. I pulled the cross off at the front rear end. Drive train looks good from there to front.

I have a CRD 203. If peanuts and cam are in the power divider, can I remove this section in order to replace or do I have to remove the whole CRD 203 from the carrier? Are they located in the first section with the air actuator?

Thanks for everyones help and input!

Allan

Take the bolts out right behind the powerdivider it will come out. Ron

[MACKS]

Sounds like you found the problem but since the power divider shares the same oil as the rest of the rear the metal filings could be coming from anywhere,I would pull the side cover off and have look inside,Good luck

[allfritz123]

Well, I took the power divider apart and yes the peanuts are in pieces and the inner cam looked like it had gone through a war!! I decided to change out the outer cam too because it has some damage that I can feel with my finger. Some grooving (maybe be okay) but I want to fix it right.

I am trying to get the big nut off that holds the outer cam on. It is a 3" skinny nut and requires a deep socket to get onto (about 3" depth to get over the shaft. I talked to my local Mack service rep and he tells me it is torqued to 1400 ft-lbs. I had to make a 3" socket because I can't find one here in Canada. My 950 ft-lb 3/4 impact won't break it. So I tried a torque multiplier (x4)(1/2 to 3/4) and I lose to much that I can't swing it all the way around. Frame in the way etc. etc. I guess I may have to bite the bullet and take it to the Mack dealer and let him change it!

Does anyone know where I can get my hands on a 3" deep impact socket. Maybe I will just have to look for a regular deep or search OTC for specialty gear. I don't know who makes specialty tools for Mack?

Allan

[MACKS]

That nut may have thread lock on it and might have to be heated with a torch,a 3/4 inch gun should take it off if you have the right air pressure at the gun,also sometimes you just have to let the air gun do it's job and keep pounding until it breaks free.

[rhasler]

I would say it is good practice to replace both cams as you intend to do, but doing so will require removing the pinion assembly from the differential. It must be removed in order to press the outer cam off of the pinion shaft.

Regarding removal of the nut, Macks is probably right about the thread locking compound. There is a special fixture that has a hollow wheel nut socket that fits inside the outer cam and allows another socket to pass through and engage the nut. The fixture bolts down to the cover holes on the front of the power divider. I will attach pictures of the fixture ASAP so you get an idea of how it works.

[rhasler]

Here's a picture of the fixture

Fixture.pdf

[b61mack]

Well, I took the power divider apart and yes the peanuts are in pieces and the inner cam looked like it had gone through a war!! I decided to change out the outer cam too because it has some damage that I can feel with my finger. Some grooving (maybe be okay) but I want to fix it right.

I am trying to get the big nut off that holds the outer cam on. It is a 3" skinny nut and requires a deep socket to get onto (about 3" depth to get over the shaft. I talked to my local Mack service rep and he tells me it is torqued to 1400 ft-lbs. I had to make a 3" socket because I can't find one here in Canada. My 950 ft-lb 3/4 impact won't break it. So I tried a torque multiplier (x4)(1/2 to 3/4) and I lose to much that I can't swing it all the way around. Frame in the way etc. etc. I guess I may have to bite the bullet and take it to the Mack dealer and let him change it!

Does anyone know where I can get my hands on a 3" deep impact socket. Maybe I will just have to look for a regular deep or search OTC for specialty gear. I don't know who makes specialty tools for Mack?

Allan

If you want to take the pinion housing off take those 12 pointed bolts out, you could take it to your Mack and have them press off and on and torque the nut for you. make sure you keep the shims lined up there are oil holes in them.while you have the side cover off make sure the 2 bolts inside are tight. Ron

[allfritz123]

sorry had same message twice.

Mack_CRD_203_PDivider_Diagrams.pdf

Edited November 6, 2010 by allfritz123

[allfritz123]

If you want to take the pinion housing off take those 12 pointed bolts out, you could take it to your Mack and have them press off and on and torque the nut for you. make sure you keep the shims lined up there are oil holes in them.while you have the side cover off make sure the 2 bolts inside are tight. Ron

Good Advice. That is exactly what I am going to do. Take it off and take it to the Mack dealers so I get it torqued properly. I ended up buying a 1" impact (1600 ft-lb) and having my brother sniping down with a pipe wrench on the socket and I still couldn't get it to budge. Yes, I am using a 1/2" air line and running it at 120 PSI while the tool recommends 1/2" air and 90 PSI!

I am scared to use heat because I may wreck the $55 nut and if I reuse it could I trust it? And I don't have the fixture to lock down the cam in order to retorque it properly. I think lock compound breaks down at about 300 degF. Just curious how my costs compare to that of the US. We don't really have true capitalism in Canada as the corporations rule the country and the government basically allows them to keep out or buy out the competition so that the consumer has to pay whatever they desire to charge. Sad but true when the political parties receive their funding from the large corporations they get what they want out of the government in return.

Dollar is pretty much at par 1 Cdn dollar = 1 US dollar

Peanuts/Wedge Kit $187

Outer Cam $1056

Inner Cam $177

External Power Divider Seal $22

Peanut Cage $789

Power Divider Bearing $99

Just curious to know how badly we get hosed for our parts here in Canada! Allan

P.S. My dealer was gracious enough to give me pictures of some of my rear end details so I thought I would share and could maybe help someone else out.

[Rob]

Good Advice. That is exactly what I am going to do. Take it off and take it to the Mack dealers so I get it torqued properly. I ended up buying a 1" impact (1600 ft-lb) and having my brother sniping down with a pipe wrench on the socket and I still couldn't get it to budge. Yes, I am using a 1/2" air line and running it at 120 PSI while the tool recommends 1/2" air and 90 PSI!

I am scared to use heat because I may wreck the $55 nut and if I reuse it could I trust it? And I don't have the fixture to lock down the cam in order to retorque it properly. I think lock compound breaks down at about 300 degF. Just curious how my costs compare to that of the US. We don't really have true capitalism in Canada as the corporations rule the country and the government basically allows them to keep out or buy out the competition so that the consumer has to pay whatever they desire to charge. Sad but true when the political parties receive their funding from the large corporations they get what they want out of the government in return.

Dollar is pretty much at par 1 Cdn dollar = 1 US dollar

Peanuts/Wedge Kit $187

Outer Cam $1056

Inner Cam $177

External Power Divider Seal $22

Peanut Cage $789

Power Divider Bearing $99

Just curious to know how badly we get hosed for our parts here in Canada! Allan

P.S. My dealer was gracious enough to give me pictures of some of my rear end details so I thought I would share and could maybe help someone else out.

Damn, my backside shares in your pain also.

Rob

[b61mack]

Good Advice. That is exactly what I am going to do. Take it off and take it to the Mack dealers so I get it torqued properly. I ended up buying a 1" impact (1600 ft-lb) and having my brother sniping down with a pipe wrench on the socket and I still couldn't get it to budge. Yes, I am using a 1/2" air line and running it at 120 PSI while the tool recommends 1/2" air and 90 PSI!

I am scared to use heat because I may wreck the $55 nut and if I reuse it could I trust it? And I don't have the fixture to lock down the cam in order to retorque it properly. I think lock compound breaks down at about 300 degF. Just curious how my costs compare to that of the US. We don't really have true capitalism in Canada as the corporations rule the country and the government basically allows them to keep out or buy out the competition so that the consumer has to pay whatever they desire to charge. Sad but true when the political parties receive their funding from the large corporations they get what they want out of the government in return.

Dollar is pretty much at par 1 Cdn dollar = 1 US dollar

Peanuts/Wedge Kit $187

Outer Cam $1056

Inner Cam $177

External Power Divider Seal $22

Peanut Cage $789

Power Divider Bearing $99

Just curious to know how badly we get hosed for our parts here in Canada! Allan

P.S. My dealer was gracious enough to give me pictures of some of my rear end details so I thought I would share and could maybe help someone else out.

About 5 years ago i put airide under my B model,i had a set of 3.87 rears i wanted to install instead of the 4.42 that came with the airride. i wanted to use the power divider lock so i took the pinion housing off and took it to my Mack dealer and had it done. the 3.87 had course spline,4.42 had fine spline so i had to buy a new outer cam $350 5 years ago. the locker outer cam was about 1/2 inch longer because the notches on the front to lock in. i also had to drill and tap the back of the carrier to accept the bracket for the torque rod. Ron

[allfritz123]

I have the truck working again. Very nice and quiet and shifts better than ever. I ended up taking the outer cam assembly to the Mack dealer and he installed it. He also installed a cup/cone bearing on the back side because he felt they couldn't get the cone off without damaging it! They used 3" socket and special adapter to break the nut off to remove the outer cam. They charged 2.25 hours labor or $250 to do that! I added in CaseIH limited slip diff oil additive as MACK apparently doesn't sell it anymore. I wasn't able to torque the specialized 12 point bolts to 150 ft-lbs as I am still waiting for the spline torque adapter from Snap-0n to do this with. I tightened them as best as I could with a regular wrench and snipe. No way to get a regular 12 point socket in to break or tighten those bolts. I ended up heating them up and machining down an old 5/8 socket to get them out. They were severally rusted so I replaced all 8 bolts @$14 each. I tried taking them off one without heat and I ended up damaging one bolt so had to struggle a little to get that one off (ended up pounding on a 15 mm wrench!

Anyways, thanks for everyone's help - I really appreciate this forum.

Allan