Rear Differential Drips Oil and Noisy

[rvaughn801]

I have an '89 2WD Regular Cab with around 230k. The odometer has been out of service a few times over the years, so I don't know the exact number.



A couple of years ago, I started getting some light squealing during hot weather. I can't hear it driving, but I can hear it when I pull up to a stop sign. It isn't brake squeal, but it does sound like axle noise. The pitch will vary in tempo as I rolled to a stop.



More recently, the front pinion seal started leaking and dripping oil. I pulled the plug out and checked the level, and what came out looked pretty muddy and black.



I know I have a Dana 70 axle, and the tag says 3. 0 axle ratio. If the differential housing is a baseball diamond, with home plate closest to the ground, I have the following numbers on it:

1st to 2nd base: 43262

2nd to 3rd: 2SUA 70

3rd to home plate: 175A



My neighbor is a mechanic and offered to help me fix it if I get the parts. But he has made some unkind comments about Old Red, and in general thinks I should stop all this foolishness and get a Chevy. So I am not sure this is a good idea.



Questions:

1. If I order parts from drivetrain.com, do I have the standard Dana 70, or the Heavy Duty unit?

2. Would it be worthwhile to pull the cover off and inspect everything before ordering parts? I have a feeling if I fill it full of new oil it will leak a lot worse than it does now with the old muddy oil. What should I look for if I pull the cover?

3. My neighbor said the noise means I need a bearing kit. Are there any special instructions I should print out before we tackle this? Is there any other recommended service to do at this time?

4. If it doesn't work out with my neighbor, is there a shop in the Kansas City area (NE Kansas/NW Missouri) that would be recommended for this kind of work?



I appreciate any help you can offer. Thanks!

 

[Philip]

If your truck has a auto in it. That is a 3:07 axle ratio. If it has a stick it will be a 3:54. If it is a 3:07 axle it is a model 71U.



With the type of milage you list it is time for a bearing kit most likely. If you have the 3:07 axle don't want any longer. The ring and pinion is not avaiable from Dodge any more. You can not get them threw aftermarket eather. So don't drive it till destruction. You will be in a world of hurt trying to find a replacement R&P.



Order the factory service manual. This will give a good set of instructions to rebearing the axle. The Dodge website doesn't show them. But if you call they can get one for you. 800-890-4038



As far as your friend. Tell him for the same year model Chevy. Your lug nuts take more more torque than the Chevy diesel put outs. So why would you want to loose power by switching to one of them. Then tell him you will drive whatever he wants to buy for you.

 

[rvaughn801]

My neighbor is just irritated because he bought his Chevy new for $24k a year ago, and the best offer he could get was $14k when he wanted to buy an "employee price" truck.



So let's see:

Value drops like a rock

1/2 the miles per gallon

1/2 the payload and towing capacity

No turbo or cool diesel sound



No, I think I'll stick with the Dodge. But enough of that.



I referred to section 3 of my Dodge service manual. It talks about 8 3/8" and 9 1/4" axles -- is this information close enough to the Dana 70 to use?

 

[ARhine]

not really. Those are small 1/2 ton axles that are totaly different.



There is a shop in topeka that does offroad stuff. I know the guy who runs it and he seems to do good work. . not cheap though always. 4x4 Land is the name. You may want to check with some truck outfits though and ask around. If the bearings have spun you may need to have some machining done to the housing to fix it.



Since I see you have the 3pd auto in your sig, you have the 3. 08 axle ratio. . take care of it! Like stated they are out of production. A standard dana 70 only goes down to 3. 54, at that ratio your top speed will be around 65mph.

 

[1stgen4evr]

No you can't just add oil and keep going. Don't run it another day. If you kill the gear set, you will devalue your truck to nothing. If the tag you mention is original then you have a gear set with a 14 tooth pinion and a 43 tooth ring gear. You may also have those numbers on the tag. My 90 model does. The 3. 07 gear set is near extinct and EXTREMELY hard to find. The numbers on the cover are not meaningless but don't mean much to the user.



The light squeal any time hot or otherwise is bad news. You may already have a serious housing problem. Either of the pinion bearings may have been spinning in the housing to make the squeal. The left side of the ring gear carrier takes the most load and that side is typically the side that will show housing damage if there is any. The carrier may have a bearing hub that is eroding (also the left side most often). Yes, it would be advisable to take the cover off and look closely before even thinking about what to order. You may be buying parts you can never use if the housing is shot.



There are post on the housing being bent. You should check that out as well.



If for whatever reason you loose the axle, you next option is to find a 3. 54 axle complete and install an OD transmission. The OD will require all the connection parts that are original on those pickups, not impossible but involved.



I along with some of the more knowlegable members did a write up on putting a kit in the 70s. Check the frequently ask questions.



James

 

[rvaughn801]

I found a phone number for 4x4 Land. I will call them tomorrow. If possible, I would like to go someplace closer. But I would prefer a recommended shop over an unknown. I will fill it up with diff oil and drive it slow to get it fixed.



The loss in top speed from a 3. 54 ratio would be painful. I often run it on the floor, at an indicated 82 MPH (I think the speedo may be fast by 5 MPH or so).



With my budget, I would have to live with the 65 MPH.



What would be the other options?

- Swap in an overdrive transmission

- Fit a Dana 60 with a higher ratio (lower numerically) and weld on new spring perches, brake drum brackets, etc.

- A Gear Vendors Overdrive



Any of these things sound like big bucks.



I noticed my diff has a RWAL sensor and control. Is there any chance this still works?

 

[1stgen4evr]

If your truck is only used for transportation, the 60 would get you by for a good while. Shouldn't be all that costly as there are thousands in the junk yards. Some earlier first gen style trucks had 60s and the spacing is the same for the springs.



The 9 1/4 Chrysler axle that is on newer 3/4 ton vans would work since it has eight lugs. The gear set is available in numbers from around 2. 7 to 3. 7 maybe wider, you can check the aftermarket lists.



As to the RWAL system, you should hope that it doesn't work and would do well to forget that it ever did. (my two cents)



James

 

[rvaughn801]

Ok, now I am terrified of what I have done to my truck. I am sure I could live with a Dana 60, as I usually just haul people.



If I remove the cover, can I inspect the gears and bearings to look for damage? How about taking photos and posting them?

 

[Philip]

There are post on the housing being bent. You should check that out as well.

I am the one that posted warnings on bent housings. While you have the carrier out. Throw a straight edge across the cover flanges and measure to the axle tubes. Here is a link to a pic of my bent housing.



https://www.turbodieselregister.com/forums/showthread.php?t=56738&highlight=bent+axle+housing





You can pull the cover. But you won't see much. The main thing you would look at with the cover off is for missing teeth and contact pattern.



Everything needs to come out for a good inspection.



You could drop the carrier out. That would give you a look at the pinion. But to inspect the pinion bearings it has to come out.



Get you neighbor over and take her apart and get the bearing numbers and seal numbers and rebearing it if R&P looks good.



Now on trans swaps. A 518 with 3:07's is a good combo. You would be looking at 1500 rpm or so at 60MPH. Check my sig line.

 

[ARhine]

I by no way recommend this... but have seen it in photos and the guy is using the truck like this.



They transplanted a 1st gen drivetrain into a late 70s ford club cab. The truck had 4. 10s and the 3spd auto. So in being major farmer fab they put the divored ford 205 in behind the attached dodge 205... . backwards. They then ran the rear case in low range to gear it up by a factor of 2-1.



I have't heard lately if it was still alive or not. Just amazes me what some people will throw together.

 

[rvaughn801]

I took ARhine's advice and went to 4X4 Land in Topeka. The guy who worked on it and the guy behind the counter both drive CTDs, so Red was in good hands. The yoke was removed and a new sleeve was put on. There was a sleeve already on the yoke from a previous repair. Besides being pretty grungey and the bad pinion seal, they said the Dana 70 is in good shape. I was out the door in a couple of hours: long enough to browse the, but not go broke buying a bunch more toys. They did not even seem too offended that the front wheels don't help pull. I put about 100 miles on it today, and it is quiet and drip free.

 

[Philip]

Glad to hear it was a cheap fix.



You need to keep a close eye on these 3:07 axles. You don't want to blow one apart.



The U (3:07) coded axle is the correct letter it is the same body position a junkyard puts you in when you try to buy one.