Attention: TDR Forum Junkies I completed the task of putting all new bearings on the '97 Dana 80. I did it thanks to Quad4x4's tools and downloaded instructions. It took me 4 hours of take down on the differential bearings, and about 5 hours buildup once the bearings were pressed back on the carrier and pinion shaft.
Challenges:
Pulling and Pressing Bearings on the Pinion and Carrier - I had a local machine chop pull the bearings and press the new ones on for about $30.
Torquing the Pinion Nut - The Dana 80 calls for 470ft lbs. The chances of you having a hoist are about the same as you having a 3/4 drive torques wrench. I found tractor repair shop that would lone me a 4 to 1 torque multiplier. I set my 1/2" drive torque wrench for 120 ft lbs and used it as input for the multiplier. It required far less maneuvering room. For the Dana 80, you'll require a good 3/4" drive air impact wrench to get this nut off to begin with.
Case Spreader - The job can be done without, but its easier with. The standard tool suppliers will charge between $450 and $550 for one. I kept looking and found Complete Offraod and a case spreader for $249 and free shipping! Here's the link: Drivetrain Tools - DIFFERENTIAL TOOLS
Dial Indicator - I have a dial indicator, but I didn't have the magnetic base. The local parts stores and tools sellers like Snap On want $55 to $300 for one. I looked on Amazon.com and found one made by Grizzly which included the magnetic base, dial indicator, and calipers for $30 and change. It was more than satisfactory.
Bearing Cups - Get the cup installers that Dan sells. They made a difficult task easy even laying on the creeper on my side under the fuel tank.
What I Found Inside
The '97 has 192,000 on the clock. Dan at Quad4x4 recommends Dana 80 re-bearing at 150,000 miles. There were no whines coming from the rear end. The bearings appeared in good shape. There were no spun bearings. No damage to anything. The telling parts were the Yoke shaft and the absence of pre-load on the differential. The Yoke shaft had a groove being worn into its forward end, which is a sign that there was excessive play in the pinion shaft. If you are doing this job on one running close to 150,000 be fprepared to catch the differential after you've pulled the bearing flange cap bolts. Dan's instructions prepared me for this. Obviously there was enough wear in the bearings that all pre-load from the housing onto the differential bearings was gone. I conclude that 150,000 is the right time to replace the differential, pinion and wheel bearings.
I started with 0. 007" backlash and finished with 0. 007" backlash that varied less than 0. 001" around the ring gear.
Challenges:
Pulling and Pressing Bearings on the Pinion and Carrier - I had a local machine chop pull the bearings and press the new ones on for about $30.
Torquing the Pinion Nut - The Dana 80 calls for 470ft lbs. The chances of you having a hoist are about the same as you having a 3/4 drive torques wrench. I found tractor repair shop that would lone me a 4 to 1 torque multiplier. I set my 1/2" drive torque wrench for 120 ft lbs and used it as input for the multiplier. It required far less maneuvering room. For the Dana 80, you'll require a good 3/4" drive air impact wrench to get this nut off to begin with.
Case Spreader - The job can be done without, but its easier with. The standard tool suppliers will charge between $450 and $550 for one. I kept looking and found Complete Offraod and a case spreader for $249 and free shipping! Here's the link: Drivetrain Tools - DIFFERENTIAL TOOLS
Dial Indicator - I have a dial indicator, but I didn't have the magnetic base. The local parts stores and tools sellers like Snap On want $55 to $300 for one. I looked on Amazon.com and found one made by Grizzly which included the magnetic base, dial indicator, and calipers for $30 and change. It was more than satisfactory.
Bearing Cups - Get the cup installers that Dan sells. They made a difficult task easy even laying on the creeper on my side under the fuel tank.
What I Found Inside
The '97 has 192,000 on the clock. Dan at Quad4x4 recommends Dana 80 re-bearing at 150,000 miles. There were no whines coming from the rear end. The bearings appeared in good shape. There were no spun bearings. No damage to anything. The telling parts were the Yoke shaft and the absence of pre-load on the differential. The Yoke shaft had a groove being worn into its forward end, which is a sign that there was excessive play in the pinion shaft. If you are doing this job on one running close to 150,000 be fprepared to catch the differential after you've pulled the bearing flange cap bolts. Dan's instructions prepared me for this. Obviously there was enough wear in the bearings that all pre-load from the housing onto the differential bearings was gone. I conclude that 150,000 is the right time to replace the differential, pinion and wheel bearings.
I started with 0. 007" backlash and finished with 0. 007" backlash that varied less than 0. 001" around the ring gear.
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