| Author | Message | ||
| Steve (Steve)
Rating: N/A |
I have a 1993 6v92 with a HT 740 transmission and a Rockwell 3:73-1 drive axel. with about 171000 miles on it. the bus always made it back home with no problems. Before we left on a 1000 mile trip I pulled into a Speedco truck oil change to get a greese job and the mechanic said the drive axel was low, the oil was red and very clean. I asked what they recommended to top off the drive axel and they pumped in Lucus oil, I asked if the Lukus was ok to mix with the red Mistic oil and they said it would be ok. After 700 miles almost home I started hearing a humming whinning noise comming from the drive line. When rolling down the road I put the trans mission in N and the noise would stop. At idle in N parked there is no noise, when I put the trans in D and give it thg gass with the brakes on there is no noise, when I'm going down the road gassing on it it makes the noise, When I let upon the gas the noise is quiet, when the trans down shifts the noise comes back in between down shifts. Looking at the transmission oil on the stick is red and smells clean with no particals of anything. Does anyone think that the Lukus Oil has damaged my drive gears? I haven't pulled the fill plug on the drive yet because they put a blue mark on the fill plug after they torqued the plug. I don't know if it is the transmissiom or the drive axle problem? Any help on this subject would help Thanks Steve | ||
| TWODOGS (Twodogs)
Rating: N/A |
sounds like trans. | ||
| Macgyver (91flyer)
Rating: N/A |
Kindof sounds like a U-Joint.... But I'm not a bus mechanic. ;) -Mac | ||
| A.K.A. Captain Cry Baby (Captain_ron)
Rating: N/A |
Sounds like zzzzurrrrr hummmmmm mabee muffler bearings ! | ||
| gusc Rating: N/A |
This is very difficult to diagnose long distance! Does the noise change pitch with speed under power? If the noise is only when the rear axle is getting power it is probably the differential gears. Ring/pinion noise is usually only under load, back off on the fuel control and it stops. Of course the trans could do the same thing. It may be overfilled which could cause noise because of foaming of the lube oil. Remove the fill plug and see if any oil comes out. Torque on the fill plug is not critical as long as it stays in. If the trans is shifting ok it is probably not the problem. | ||
| BrianMCI Rating: N/A |
I personally have never heard of a "drive axle" that uses red fluid... If the differential is filled with ATF, I believe there could have been a serious lubrication problem. And from your desription it sounds exactly like differential trouble. When you are starting off under acceleration you are putting a load on the differential... When you coast with the trans in neutral, the diff is unloaded, same for idling in neutral. With the tranny in D with brakes locked and the pedal to the floor... you ARE loading the diff. but you aren't spinning it. I've never heard of Lucas Oil, but without knowing what the oil was, I couldn't say if it is harmful or not. My first route to diagnosis would be to drain the oil out of the diff and check it for particles of metal My second step would be to look in the manual and determine the lubrication reccomendations for your drive axle. Brian | ||
| Geoff (Geoff)
Rating: N/A |
If you mean Marvel Mystery Oil when you say "red Mistic" oil I would say someone unloaded a bad differential on you! --Geoff '82 RTS CA | ||
| Dan West (Utahclaimjumper)
Rating: N/A |
>>>If you are talking about the trans, it would be red and Lucas is a VERY good additive. If you are talking about the diff. or rear end, it would not normaly be red and Lucas would also be a VERY good additive...Lucas makes several additives for various uses, if the right additive was used it would not be at fault. I would also shake each end of the drive line to check the U joints.>>>Dan | ||
| John that newguy Rating: N/A |
Oooo-kay: -I started hearing a humming whinning noise -When rolling down the road I put the trans mission in N and the noise would stop (free-wheeling and engine near idling) -when I'm going down the road gassing on it it makes the noise (In gear and under power) -When I let upon the gas the noise is quiet, (Engine "idling"; trans is freewheeling) -when the trans down shifts the noise comes back in between down shifts. (between shifts- freewheeling/idle) Transmission normal sounds, or alternator whine, or power steering pump whine. | ||
| TWODOGS (Twodogs)
Rating: N/A |
wheel bearing | ||
| A.K.A. Captain Cry Baby (Captain_ron)
Rating: N/A |
Tail light push rods | ||
| Jtng Rating: N/A |
Cat stuck under left rear tag axle. | ||
| Jtng Rating: N/A |
Ron hiding in bathroom (whining). | ||
| A.K.A. Captain Cry Baby (Captain_ron)
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HA-HA-HA | ||
| A.K.A. Captain Cry Baby (Captain_ron)
Rating: N/A |
HA-HA-HA | ||
| Jtng Rating: N/A |
 | ||
| BrianMCI Rating: N/A |
Well, I don't believe it's the alternator or power steering based on the info so far, that also goes for the tranny... but doing a check of the u-joints is a wise idea as well as examining the diff. Brian | ||
| gusc Rating: N/A |
I'm going to disagree with a few of these ideas, at least the serious ones. I doubt you can hear the alternator over the engine. PS would be only make noise when turning and then I doubt you could hear it all the way back in the engine comp. Wheel bearings?? Power or no power won't affect a wheel bearing noise. Sometimes wheel bearings change sounds on curves but that is usually the front wheels only. Universals would more than likely make a clicking sound, not the whining/singing sound that diff gears make. Pontiacs back in the late '40s were infamous for this. Bad universals will also cause vibration which changes drastically with higher speed. A small amount ofMarvel Mystery Oil added to the diff couldn't do much damage. A big dose could. It is essentially a solvent with some lubricating properties. I have no idea what "red Mistic or Lucas oil" are? Are these the latest "Snake Oils" on the market? When you find out for sure what is causing this sound be sure to let us know! | ||
| gusc Rating: N/A |
I didn't read BrianMCI's post closely enough; "If the differential is filled with ATF, I believe there could have been a serious lubrication problem. " I think he may have the answer. I, too, have never heard of red gear lube. Is it possible that some person thought this was a transaxle like on front wheel cars? They use red tran fluid!! Or.....maybe it really is a transaxle? I'm not up to date with '93 buses at all. | ||
| Roger Rating: N/A |
Might as well put my two bits in! As I have various heavy trucks, it sounds like the differential to me. Drive it around alittle to warm up the differential, drain the oil out of the differential catching a half pint of oil for a sample. Fill with a good 80-90w gear oil. I bet you wont have any more noise. If you are nervious about the condition of the differential, about any damage that may have occured, send in the oil for a test. They will tell you with much accuracy the condition of your diff. I would flush it again after a thousand miles or so. Lucas oil has been around for a long time. Go in almost any truck stop and what do you see-Lucas oil. I use it in all my front wheels and tag axles. For buses use it in your mitre boxes. It will lowered your box temperature.Seen many many gear oils, never red!! | ||
| John that newguy Rating: N/A |
You have an MCI Steve? It takes sae140 for the rear end/diff. The alternator can be heard over the engine. The power steering pump can be heard over the engine.... The transmission on mine has a whine and most do... But you oughta' check the fluid level. I had a bus garage do an oil change and lube and the shortchanged the tranny by about four quarts. They also almost put the wrong fluid in the tranny.... Second guess anyone; don't expect correct actions. It does sound like a rear end problem, but that's a worse-case scenario. Look for the simple things first. Cheers! | ||
| Macgyver (91flyer)
Rating: N/A |
Well, since there are people pointing fingers at Lucas...  It's an excellent product, and they make additives of all kinds. I use their engine products quite a lot on my road skippers (cars/vans/pickups, etc)... I've seen improvements ranging from less smoke on a smokey engine to cooler temps in the summer time heat... I trust their products without question... I've also used Marvel products, and although they are good... they aren't as good as Lucas in my opinion... but then, Lucas is twice the price! -Mac | ||
| A.K.A. Captain Cry Baby (Captain_ron)
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Gusc Beleive me an alternator can be louder than your engine. | ||
| Ed Roelle
Rating: N/A |
I had a similar noise and it turned out to be the ring and pinion. Since they were damaged, I replaced them and installed Shell gear lube. After 5000 miles, a slight moan type noise reoccurred. I changed the fluid again but this time to Chevron. Noise is gone for now. Rear axle ring and pinions require a 'sticky' type lubricant (gear lube) because of the sliding friction. Ed Roelle Flint, MI | ||
| Brian (Bigbusguy)
Rating: N/A |
Lucas oil is Crap . Yes its at every truck stop every parts store. Well Il tell you when I had my oil changed in my Peterbuilt trans they pushed how good it was. So I let them add it. Well about 2000 miles later the trans blowed up. I would pull a oil sample and find out what type of oil is in there . It may have been a Synthetic type of oil in there and adding a oil additive may have goooed it all up you cant mix some types of oils. You may have a claim with the shop that added the oil. If its a rear end noise the dammage is done It sounds like a pinion bearing going out. Not to costly to fix .But keep driving it .YOU WILL DAMMAGE IT BAD. And some newer 1 ton trucks run ATF in the Diff now. I dont know about bigger ones but Thay may also now. Oils and rear ends have have changed now and you just dont put 90/110wt oil in every thing any more. You bus may have a newer rear end in it. Brian 4905 Klamath Falls Oregon | ||
| doctor al Rating: N/A |
most likely the rear end. I believe it was amsoil that made a red colored synthetic rear-end oil. Brian is right, pull a sample and have it checked. | ||
| gusc Rating: N/A |
I stand corrected on PS and alternator noise. On the old diesel trucks and fire truck I own you can't hear a thunderclap! The trucks engines are in front and the fire truck's is right behind the cab so it is hard for me to imagine how one could be heard anything 35'-40' to the rear. Of course I have a high frequency hearing loss from too many hours in airplanes so that may be part of my problem! | ||
| gusc Rating: N/A |
Some of my old truck diffs use 140xp oil, some use 90xp and some use 90 mineral oil (Non-xp) so it is a must to find out exactly what type is needed. My '53 GMC five ton 5sp trans uses 50wt mineral oil and has a trans oil pump so, as Brian said, you shouldn't just dump 90wt into every trans. Newer machines probably all use xp but I don't know that for sure, it pays to check. | ||
| John that newguy Rating: N/A |
Steve- This is probably going to sound stupid, but..... after removing all the seats in my bus, had heard a horrific amount of noise and whine on my trip back. As soon as I'd slow down, the noise would quiet. At speeds over 60 (I had been running 75-80), the noise would commence. Under the rear bench seat and on the floor directly in front of it, are access points. Each are about a foot or so square and held down by one screw. When my seats were removed, the one under the bench seat no longer was held down by the seat (the screw was missing). With enough speed and the fan blower pushing high volume of air, the access cover would pop up. It was an open door to the engine compartment and all the noise it holds. Sooooooo.... I'm wondering..... as foolish as it may sound... if they may have opened the hatch to access the tranny, air cleaner, air dryer, alternator.... and not secured it? Any whine any device makes back there normally, would sound like all hell with that hatch open... | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
Steve, our 4106 differential was noisy with 90 wt. in it. It was bad enough that it had me really concerned. When I saw that GM wanted 140 in it, I got it changed. The noise dropped way down and seems to have continued to fall with use. I can hear it now at some speeds, but it doesn't seem loud enough to justify doing anything about it, other than keeping the differential full. I hope that yours is no worse to deal with. Tom Caffrey PD4106-2576 Suncatcher |