Noisy rearend

[MudPuppy]

1981 SX/4 I6 fulltime 4x4 with 2.73 gears


There has been a slight howling coming from what sounds like the rear. I see my pumpkin has some old crud and a little fresh oil oozing from it. So sometime in the near future I plan on tearing into it to at least replace the gasket and change out the oil (if there is any left). ETA: fluid is full. Couldn't get bolts off even with heat, lots of lube & cheater bar.

ETA: last time it was driven a bit of a distance, no rims were hot. IIRC it would howl at any speed.


Have read on other sites that it could possibly be the pinion and ring gears, axle bearings and/or carrier bearing, and so on   
- But am I missing anything else?
- Any tests to narrow it down to know exactly which it is?

I am trying to compile a list of items needed (just-in-case/worse-case scenario) to rebuild the whole rearend (bearings, seals, lubes, parts #'s and/or where to find them, etc.).
I was told it's the Timken set  #6
Rear inner seal is National 7686S and outer is 8429S
seal on the back of the hub is 21961 (NAPA) or Timken 3553

Also a good price estimate for someone to do the work? So I don't get screwed.



What would need to be on this parts list? Please do it in sections (i.e hubs need these parts, axle needs these parts, diff needs these parts, etc.).... remember- simple, simple
Also I think doing lists like this would be very helpful for Eagle new comers, non-mechanically inclined (like myself), etc. so really it should be helpful and easy for all.

OR
Is there a better alternative out there? Not wanting to do something super radical or expensive ( though I wish I could), just looking at the alternatives and maybe something a bit stronger.
*Just looking into this option, not sure which way I will end up going. So input on either/or is still appreciated*

If giving an alternative, please also state what all is needed to swap out and over, parts list, price estimate on said parts, any mods, etc., etc.


ETA: I have a 1990 Dodge Dakota 4x4 at my disposal if anything off it would work as well.

[eaglebeek]

It's possible you have a wheel bearing making the noise. You would know it by changes in intensity of the sound when you make turns. 

[1985amceagle]

If you would get into rebuilding the axle your self, you might want to make sure you have a good understanding on how to set pinion depth, back lash, and gear contact patterns.

[SpreadEagle]

Sorry to hear about the rear. I've got issues along the same lines. But I think the axle related is a hub and the other is off topic and often bean related. I hope to have 2 spare 2.72/.73 axles shortly if it may help.

[drock87]

DO NOT drive it like this! I believe you probably have a bad pinion in your rear end, likely in axle shaft. I ignored this, and my rear end blew up resulting in my wheel flying off with the half shaft attached to it. Don't let this happen to you! It actually destroyed the hub and prevented my rear end from being rebuilt.

[MudPuppy]

I haven't driven it since finding this issue other than around the yard ocassionally. When I first got the car & drove it home (maybe 30 miles) it had a horridly loud noise from the front and a super hot rim- turned out to be a caliper dragging but went ahead and had the front bearings replaced too. When it was tore into, the front bearings looked pretty new and were even stamped "Timken".
Then would drive it down the road to test it out & that's when I noticed the rear noise. And my drive wouldn't involve any turns really (slight ones here and there) so I couldn't say that it gets more or less intense. IIRC, it seemed the same intensity whether on the gas or not. Seemed to die down when speed decreased & of course increase in intensity with speed.
I have tried & tried to pinpoint where this noise is coming from exactly but it's impossible.
I won't be doing this work myself, I think it would be best to find someone who does this sort of thing.

[Monkeyjoe]

My SX-4 had that growly noise, I replaced the bearings, and it solved the problem.

[MudPuppy]

My SX-4 had that growly noise, I replaced the bearings, and it solved the problem.

I guess I could start there, probably the cheapest thing right now. And if that doesn't solve the noise issue then it would have to be the differential.
Is my list above correct?


Timken set  #6 (2 sets)
Rear inner seal is National 7686S and outer is 8429S
seal on the back of the hub is 21961 (NAPA) or Timken 3553

How many of these seals are needed? Just 1 per side?

[MudPuppy]

Looking into parts I now have a few questions.
Wheel bearings wise:
Are the rears tapered? Seems as some (parts distributors/manufacturers) mention their bearings as tapered and others don't mention it at all.
Also is there just the 1 inner bearing on the rears per each wheel?


Also regarding rebuilding the whole rearend:
I see they (parts distributors/manufacturers) say things like -
USA STANDARD GEAR Part # ZBKM35 Bearing Kit
Rear Diff; 4WD; AMC Model 35 Rear $57.79
NATIONAL Part # RA335J Bearing/Oil Seal Kit
Rear; AMC 15; 7.506" R.G.  $60.79
SKF Part # SDK335 {#DK335, DK335J} Differential Rebuild Kit
Rear; Standard Kit; Dana 35 Axle $78.79

(regarding the stuff in blue) A bit irritating (& confusing) when some say "amc model 35 rear", "Dana 35 rear", "rear AMC 15", etc.
I assume either one would work? 1 in the same.

[Monkeyjoe]

Yes, one bearing that is pressed onto the axle shaft and it is a tapered bearing.

[Mernsy]

These may help.

http://amceaglesden.com/guide/index.php?title=Group_8_Brakes_--_Wheels

http://amceaglesden.com/guide/index.php?title=Group_9_Axles_--_Propeller_Shafts

[MudPuppy]

Yes, one bearing that is pressed onto the axle shaft and it is a tapered bearing.

Thanks MonkeyJoe.
Since you've replaced your rear bearings before is my list correct:
- Timken set  #6 (2 sets)
- Rear inner seal is National 7686S and outer is 8429S
- seal on the back of the hub is 21961 (NAPA) or Timken 3553

Missing anything?

These may help.

http://amceaglesden.com/guide/index.php?title=Group_8_Brakes_--_Wheels

http://amceaglesden.com/guide/index.php?title=Group_9_Axles_--_Propeller_Shafts

Thank you Mernsy.
I was looking at those the other day and that is one of the reasons I was asking if the rears are tapered bearings or not lol. Can't really tell from the pictures, if anything they don't look tapered at all. Really wish I could zoom in on those illustrations sometimes.

[Mernsy]

Really wish I could zoom in on those illustrations sometimes.

On a PC you can hold down the Control key and zoom using your scroll wheel.

[MudPuppy]

Really wish I could zoom in on those illustrations sometimes.

On a PC you can hold down the Control key and zoom using your scroll wheel.

Oh wow! I had no idea! Learned something new today lol. Thank you Mernsy! That helps a ton.

[Mernsy]

Welcome.