Metallic sound while coasting

[99EB5.0]

Ive got a 1999 5.0 Awd. When i let of the gas and coast I hear a metallic rubbing sound from underneath. Cant tell if its from the front or rear, just that its there. Goes away when i accelerate but is right back when I let off. Just replaced the fluid in the front diff and transfer case and am waiting for the fluid for the rear diff to get here. Any ideas?

 

[99EB5.0]

Anybody?

 

[gavin]

possibly the CV joint at the t-case end of the front driveshaft starting to go.

 

[99EB5.0]

How difficult is this to replace? Is is something i can just buy or is it more than just the joint? Is this actually a cv joint and not a ujoint? I don't mean to sound retarded but i don't have much experience with AWD applications. Thanks for your help

 

[99EB5.0]

I got up under the truck and saw what i believe you are referring to. Its pretty rusty and wet with what id imagine is grease. Any write up on checking this and or replacing? Thanks again

 

[gavin]

well, for checking it... you can try chocking the tires and putting the truck in neutral. Then feel how much rotational play there is in the shaft.

Only other way to really check it is to remove the shaft and test drive.

Now, nobody really know how much if any damage can be caused by driving around without a front driveshaft, due to the design of the 4404 AWD t-case.

You could probably get the joint replaced by a driveline shop, but most find it easier to just buy a new shaft. Unfortunately they cost around $300 or so, if I remember correctly.

The cv joint itself I've seen for around $60 I believe.

The issue with just replacing the CV joint, though, is that there could be wear marks on the driveshaft itself, where the joint fits on to. If there is enough wear, you will get premature wear on the joint.

 

[99EB5.0]

well, for checking it... you can try chocking the tires and putting the truck in neutral. Then feel how much rotational play there is in the shaft.

Only other way to really check it is to remove the shaft and test drive.

Now, nobody really know how much if any damage can be caused by driving around without a front driveshaft, due to the design of the 4404 AWD t-case.

You could probably get the joint replaced by a driveline shop, but most find it easier to just buy a new shaft. Unfortunately they cost around $300 or so, if I remember correctly.

The cv joint itself I've seen for around $60 I believe.

The issue with just replacing the CV joint, though, is that there could be wear marks on the driveshaft itself, where the joint fits on to. If there is enough wear, you will get premature wear on the joint.

Okay. Ill start with checking the "rotational play"

Anyone else want to chime in with their experience in removing the front driveshaft? If taken out itll be for a total of about 10 minutes to see what it does, any chance any damage will be done in that time?

I love this truck yet this little issue is driving me nuts.

 

[SmoothJimmy]

From my experience, removing the front drive shaft will make the sound go away. HOWEVER, it will not necessarily identify the front drive shaft as the problem.

CAUTION: Removing the front driveshaft will allow the car to roll while in park...and the e-brake on these rigs are prone to slippage/failure. Plenty of guys have found their Ex's down the road after making these assumptions.

If you do remove the shaft, check the shaft joints for play. If sloppy, then you may have your problem. ALSO, check the play on the flange at the 4404 transfer case. If there's a good bit of rotational play, you may have your culprit....a stretched transfer case chain -and/or- worn transfer case sprockets. In this case the sound you are hearing while coasting is possibly the loose chain running/rubbing on the backside of the sprockets.

Do you also get a 'whine' while climbing/turning? This may be symptomatic of worn t-case innards. Climbing/turning places a load on the transfer case as the fronts are trying to turn at a different rate that the rears and the viscous coupling is warming up and placing load on the sprockets/chain. The worn chain/sprocket interface can cause wear/noise in unanticipated spots.

I suggest AGAINST leaving the front driveshaft out for an extended period of time even though you will be amazed how smooth the Ex drives without it. One reason is safety (above) and the other is potential damage to the viscous coupling. From my analysis, the viscous coupler is forced to heat up and stay locked ALL THE TIME while the front shaft is out. Though there isn't much to spin (innards of the case), there also isn't the complimentary force of the front wheels 'driving' the front of the case (as in normal non-wheelspin driving).

For xfer case longevity on the AWD, it is recommended that you never replace front or rear tires only, DO rotate your tires at regular intervals and DO frequently check/adjust air pressure. Any diff in tire diameter front/rear will load the case.

 

[99EB5.0]

I do not get a whining when turning/ climbing. Its the coasting sound and the sound of worn wheel bearings which are fine. I've got a good selection of salvage yards around me which plenty of explorers to choose from and a driveshaft is only 30 bucks at these places. Im thinking ill grab a couple and swap mine out and see what i get. Thanks for the help so far guys. Any other suggestions are more than appreciated.

 

[99EB5.0]

Well, I pulled of the front shaft and took it around the block. Silent. No noise whatsoever.
While I had it off I noticed that there was no grease inside the cv joint, it clunked around so Im leaning towards that being the culprit.

On another note, i marked the position of the driveshaft when i removed it, and when putting it back on i may not have had the front in the same position. I have no new noises or anything else new for that matter. Think I have anything to worry about? Im going to go junkyard hopping on Monday and grab a couple shafts, yet how am I supposed to know which position to install the "new'' one?

 

[gavin]

honestly, for me it's never mattered whether or not I kept the orientation the same when reinstalling.

chances are, you don't need to worry about it.

and if the joint is dry of grease, then yeah I would say 99% chance that is the culprit.

junkyard shaft may get you a hundred to even thousands of miles, but plan on getting a new one. Just something to think about.

 

[99EB5.0]

Well id like to just buy a new one and call it done but 300+ doesn't work for me right now. I know of a couple lower mileage explorers in the junk yard so ill go with that and see how it goes. Thanks for all of your help. Id be lost without this forum

 

[gavin]

you might get lucky
the first junkyard shaft I got lasted quite a while

 

[99EB5.0]

Now just for kicks, my cv boot looked pretty intact it wasn't torn up...what kind of grease would i use to inject into the boot?

 

[gavin]

I've just used some high temp grease.
But you really should use actual CV grease.

at least something compatible with the existing grease, or what's left of it. I do not know what kind of grease is OEM.

I know Red Line makes synthetic CV grease.
http://www.amazon.com/Red-Line-8040...AEJA/ref=sr_1_1?ie=UTF8&qid=1304542714&sr=8-1