Rumbling noise

[doonboggle]

When I retrieved my 81 diesel pickup from the local guru shop about 2 weeks ago, it was running like a new toy top. Good acceleration, decent mpg, driving nice ... everything. I had the engine tuned and other little items in the engine bay addressed that I could not access due to back problems.
Also had front struts rebuilt, which included the shocks that are guaranteed for life; forget the name at this moment but seem to recall it being KB or something like that. Before the front end was extremely squishy-skousy ... but now is firm.
Tires are new, and had the front end aligned from a wishbone condition to 'almost' straight ahead.

Now, in the last few days, initial startup the engine is louder than it was when I first retrieved it. In addition, on the road, at 55-60 mph, there is a steady constant deep rumbling noise. Nothing seems to be affected ... but the noise is some concern to me.  Steering is good; gauges not advising of problem; temperature normal; etc..... and mpg today after a 110 mile trip was exactly 50 mpg.

What would the suggestions be for me to check or perform to try and track this down; or am I imagining something that is irrevelant?

My analysis comes from a memory of a new 1981 rabbit sedan we had in 1982 that was quite as a bump on a log ... considering it was a diesel of course ... normal noise of which I relate to A-OK.

[rabbitman]

See if you can repeat the rumble in neutral sitting still by revving to about cruise rpm and a little higher and lower. My wild guess would be that the timing belt is flapping between the tensioner and crankshaft.

[maxfax]

Make sure the timing cover is tight as well.. 

Another check would be to make sure the exhaust is secure and not rattling against anything..  Seems to be a common ailment for me as of late.. The old rubber hangers left go, and the new cheapo Chinese ones are, well, cheapo Chinese crap..

[doonboggle]

Was going to address some of the suggestions today when, after raising hood, noticed a puddle of oil underneath engine.  Do decided to address that first by hooking up to hot water heater and blasting off as much of the recent dropings as I could ... in order to try and determine the source.  Did have the shop last month check and otherwise change to tranny oil ... so suspected that ... along with loose oil pan bolts.

Turns out nothing from oil pan nor tranny area.

I'm not a mechanic, so please don't giggle with the following.  Where the front axles join under the engine area ... on both interior ends ... is the seepage.  Having no experience in this area, I tried to find what I could see while flat on my back in the pages for front end steerage, etc ... but could not determine what I am talking about.

Again, from each front wheel into the middle, where their shafts-axles-? join, is where the seepage is.

What would this be ... in laymans terms ... rather than dummie like me.
Thanks

OH .... and could this be related perhaps to my rumbling?
I have had small oil droplets just after the shop visit ... but not as bad.  Theorized it was loose bolts ... but now with the long trips (110 miles yesterday-round trip for groceries), it has increased notability.

[redneck_vdub]

Wheel bearing maybe?

[doonboggle]

What would determine that once I have the wheels of; loose rollers-balls-etc. maybe??? 
Any other???
Would you suggest all wheels be checked. 
I did, about 6 months ago, rebuild the braking system and took all 4 off ... and noticed nothing at that time.
Thanks

Wheel bearing maybe?

[maxfax]

Again, from each front wheel into the middle, where their shafts-axles-? join, is where the seepage is.

What would this be ... in laymans terms ... rather than dummie like me.
Thanks

OH .... and could this be related perhaps to my rumbling?

The axles are bolted to flanges that are coming out of the transaxle..


Do you notice the oil coming from where the red arrow points, or the orange arrow? The axle bolts on to where the orange arrow points..  IT is possible that the axle bolts could be loose and allowing the grease to leak out.. This would also cause a rumble when driving..  If the oil is coming from where the red arrow points that would be the seal where the axle flange goes into the transmission allowing trans oil to leak out....    

Sometimes when a wheel bearing is bad you can jack the car up and see if the wheel will wiggle about.. Pends how bad it is if the wheel will wiggle.. Usually the bearing has to be pretty bad to be able to spin the wheel by hand and be able to hear it, especially on the front wheels..

 For me the tell tale has always been to see if the noise changes if you swerve (such as changing lanes quickly)..  When the weight shifts off the offending wheel (and bearing) it will usually get quieter..  This test would at least alert you to whether it is a wheel bearing, and which side of the car it is on...

[doonboggle]

Thanks Max; that helped a lot.
Looks like I need to alter my initial comment when I said the tranny was not leaking.  From above looking down at the tranny, I had overlooked the section that sticks out toward the rear ... and did not associate that section as where the front axles would join.  I know... I know .... DUH !!!

Based on the image you provided, the large silver part is a bit different than what is on my pickup, but from the flutes I can see that ... on both sides of it where the axles join, is seepage as where your red arrow points.  Back where the orange arrow is, and the rubber boots ... all dry and clean.

Immediately beneath the flutted section is a drain plug ... presumably for the tranny oil....but it too is not leaking .... just above where apprently seals would be installed.
I did not see anything that I could tighten ... so am presuming this is another shop call.

It's strange that during the year that I drove the truck now and then ... albeit not that much highway miles ... that there was no 'noticable' leakage.  A smidgen ... but not over 2-3 drops now and then.
Yet now enough to become concerned.  The highway trips we've recently implemented must have stired up things inside ... or broke down the inter seals....both sides.

TIA



[/quote]The axles are bolted to flanges that are coming out of the transaxle..


Do you notice the oil coming from where the red arrow points, or the orange arrow? The axle bolts on to where the orange arrow points..  IT is possible that the axle bolts could be loose and allowing the grease to leak out.. This would also cause a rumble when driving..  If the oil is coming from where the red arrow points that would be the seal where the axle flange goes into the transmission allowing trans oil to leak out....    

Sometimes when a wheel bearing is bad you can jack the car up and see if the wheel will wiggle about.. Pends how bad it is if the wheel will wiggle.. Usually the bearing has to be pretty bad to be able to spin the wheel by hand and be able to hear it, especially on the front wheels..

 For me the tell tale has always been to see if the noise changes if you swerve (such as changing lanes quickly)..  When the weight shifts off the offending wheel (and bearing) it will usually get quieter..  This test would at least alert you to whether it is a wheel bearing, and which side of the car it is on...[/quote]

[Henchman]

Just to add more possibilities, my waterpump bearing is failing and is creating a deep rumble (hard to hear at fist until you tune into it).  As for the oil seepage from the diff area, probably a leaky seal behind the flanges.

Ian

[maxfax]

I think you had mentioned having the tranny oil changed..  Sometimes just a different brand of oil will make old seals decide to leak..  Fortunately replacing those seals isn;t a real involved job, but they are not located in the nicest of places to work, especially for one with back problems.  There is the possability that the oil in the trans could be low causing some rumble..  You may want to check the level..

[doonboggle]

Was finally able to get the plug loose.  Had to make a tool from a connector from local hardware; 1.89 versus something near 15.00+- as per google search.

After lowering the truck off of the ramp, and unscrewed the plug again, it immediately began to leak oil that 'looked' clean; so immediately put plug back in and tightened. 

So low oil is out.

But with the ever so slow leak coming out of both sides of the axles, want to replace those seals that seem to be deteriorating.  Went to google again, and it seems that there are a couple of different sizes of the seals.

Without having to wait for the axles to be off and the old seal removed, is there a way to determine the size that is needed ... so that I can pre-order and have them ready for the guru to R&R?

The truck is a 1981 with the 5-speed ... but that definitive search words did not indicate.
TIA

I think you had mentioned having the tranny oil changed..  Sometimes just a different brand of oil will make old seals decide to leak..  Fortunately replacing those seals isn;t a real involved job, but they are not located in the nicest of places to work, especially for one with back problems.  There is the possability that the oil in the trans could be low causing some rumble..  You may want to check the level..

[rabbitman]

If that's actually the original tranny it would be the smaller seals, IIRC they switched to the large ones sometime in the late '80s.

[maxfax]

If that's actually the original tranny it would be the smaller seals, IIRC they switched to the large ones sometime in the late '80s.

I think it may have been '85 or '86 when they changed... Take note of the pic I posted earlier in this thread..  Notice the green collar where the red arrow is pointing? That collar would be right inside the flange for the passenger side axle..  IIRC if you have the green collar it's the larger seals, if not it's the smaller.

[doonboggle]

I think it may have been '85 or '86 when they changed... Take note of the pic I posted earlier in this thread..  Notice the green collar where the red arrow is pointing? That collar would be right inside the flange for the passenger side axle..  IIRC if you have the green collar it's the larger seals, if not it's the smaller.

With help of spouse, was able to crawl under again. 
You mention 'right inside the flange' for pass. side. 
This is a 1981 version, which is slightly different than the image you posted.
Could not determine if there was a color to note. 
Is there something I need to be taking off first?
Thanks

[maxfax]

The picture is of the later model transmission.. Sounds like you still have the original trans, which *should* be the smaller seals..

Part Number:

Carquest 474288
Napa NOS14040
National (Federal Mogul) 474288

And most part suppliers should be able to cross one of these numbers to their product line..

And alternate number from National would be 8660S..  That's actually a very common Ford/Chrysler axle seal but is dimensionally the same, except the catalog has the measurements in standard instead of metric..