Engine/Transmission (1994 - 1998) leak at Dana 80 rear end

[purdytj]

Hi,

I put on a Mag Hytec rear diff cover about a year ago. I filled it per the specs and checked the level using the May Hytec dipstick. There has been a leak where the drive shaft goes into the rear end gear housing. See photo.



It was not there before the rear diff cover install, so I'm thinking the truck never had the gear oil changed / filled properly - or at least not for many years. The oil was probably low when I purchased it (October 2010) and now that I have the correct amount in there it leaks.



Thoughts? It is making a mess on anything I tow, the spare tire, and my tailgate.



Would a transmission shop need to repair the seals or the like?

 

[JKosten]

That looks like a pinion oil seal leak.

If you have the tools and a service manual you can do it your self or take it to a transmission and axle place.

If it has been run low on oil for an extended time you should check the gears and bearings.

 

[hsmith]

Not an uncommon problem, also unrelated to the new cover install.

 

[WDixon27]

how i universally do pinion seals is to make a punch mark on the pinion shaft and nut so as to not tighten it more then that point and disturb any crush sleeve setting if it exists on whatever diff i am working on.

mine is starting to seep too but haven't had time to change it and i noticed one thing that may of put excessive stress on it, the u-joint doesn't totally fill the saddle on the pinion flange by around 15 thousandths, it has the original spicer joint and a new joint had the same size difference so i shimmed the caps on the joint out to center the joint in the saddle, i used ac compressor clutch spacers and it actually eliminated a highway speed buzz i wasn't looking for which should help the pinion bearing live longer

 

[Extreme1]

The Dana 80 doesn't have a crush sleeve but the torque on the nut is 450 ft-lbs so the punch mark is the way to go. I did mine at my friend's repair shop and it took his largest imact wrench hammering on it a while to get it loose but the seal replacement was normal.

 

[Bob4x4]

PINION SEAL

REMOVAL

1. Raise and support the vehicle.

2. Scribe a mark on the universal joint, pinion yoke, and pinion shaft for reference.

3. Disconnect the propeller shaft from the pinion yoke. Secure the propeller shaft in an upright position to prevent damage to the rear universal joint.

4. Remove the wheel and tire assemblies.

5. Remove the brake drums to prevent any drag. The drag may cause a false bearing preload torque measurement.

6. Rotate the pinion yoke three or four times.

7. Measure the amount of torque necessary to rotate the pinion gear with a (in. lbs. ) dial-type torque wrench. Record the torque reading for installation reference.

8. Hold the yoke with Wrench 6719. Remove the pinion shaft nut and washer.

9. Remove the yoke with Remover C-452 Yoke Removal

10. Remove the pinion shaft seal with suitable pry tool or slide-hammer mounted screw.

INSTALLATION

1. Clean the seal contact surface in the housing bore.

2. Examine the splines on the pinion shaft for burrs or wear. Remove any burrs and clean the shaft.

3. Inspect pinion yoke for cracks, worn splines and worn seal contact surface. Replace yoke if necessary

NOTE: The outer perimeter of the seal is pre-coated with a special sealant. An additional application of sealant is not required.



4. Apply a light coating of gear lubricant on the lip of pinion seal.

5. Install the new pinion shaft seal with Installer D-187-B and Handle C-4171

NOTE: The seal is correctly installed when the seal flange contacts the face of the differential housing flange.



6. Position the pinion yoke on the end of the shaft with the reference marks aligned.

7. Seat yoke on pinion shaft with Installer D-191 and Wrench 6719 Yoke Installation

8. Remove the tools and install the pinion yoke washer and nut

CAUTION: Do not exceed the minimum tightening torque when installing the pinion yoke retaining nut at this point. Damage to bearings may result.



9. Hold pinion yoke with Yoke Holder 6719 and tighten shaft nut to 597 N·m (440 ft. lbs. ) Tightening Pinion Shaft Nut Rotate pinion shaft several revolutions to ensure the bearing rollers are seated.

10. Rotate the pinion shaft using a (in. lbs. ) torque wrench. Rotating resistance torque should be equal to the reading recorded during removal, plus an additional 0. 56 N·m (5 in. lbs. ) Check Pinion Rotation Torque

11. If the rotating torque is low, use Yoke Holder 6719 to hold the pinion yoke Tightening Pinion Shaft Nut and tighten the pinion shaft nut in 6. 8 N·m (5 ft. lbs. ) increments until proper rotating torque is achieved

NOTE: The bearing rotating torque should be constant during a complete revolution of the pinion. If the rotating torque varies, this indicates a binding condition.



12. Install the propeller shaft with the installation reference marks aligned.

13. Tighten the universal joint yoke clamp screws to 19 N·m (14 ft. lbs. )

14. Install the brake drums.

15. Add gear lubricant to the differential housing, if necessary. Refer to the Lubricant Specifications for gear lubricant requirements.

16. Install wheel and tire assemblies and lower the vehicle.

 

[purdytj]

Thank you everyone!!!