dana 20 rear output change?

[oldiron]

Driving home today I started to notice a little vibration at speeds over 50.
Got it home and started checking all the usual suspects and discovered that there is a lot of "play" in the rear output of the dana 20. By play I mean side to side and up and down, the seal has obviously given up too, fresh oil coming out. I've looked at a few rebuild tutorials and my question is.....
Are the rear output assemblies interchangeable? I have a spare dana 20 with a tight output assembly. Can I simply remove the loose one and install the tight one without removing the t case? Are special tools required?
Greg

 

[garberz]

Yes, you can change it out. Just be aware of the 13 roller bearings tucked inside the opposite end of the output shaft. They can easily fall to the bottom of the case. We just did a trail fix recently, luckily the roller bearings came out with the output shaft assembly
Mark

 

[garberz]

No special tools. 45 min. job.

Mark

 

[oldiron]

And this can be done with the t case still in the truck? Best news ive had all day.

 

[garberz]

And this can be done with the t case still in the truck? Best news ive had all day.

Yup, pull the rear drive shaft and speedo cable, a few bolts, and the entire assembly comes right out. Just keep an eye on those roller bearings.

Mark

 

[72Sport]

If you plan on using grease to hold the 13 bearings in place use petroleum jelly instead. The 13 bearings seem to serve as part of an oil pump to get oil to the bearings in the rear housing. The 3 1/8" dia holes in the rear of the cavity for the bearings are actually a part of the "oil pump" for the rear bearings. The holes are angled at about 45 degrees so oil is sprayed on the face of the rear housing when rear shaft is rotated at driving speed. The rear housing has two holes in the face to serve as oil passages. The triangular hole at the top collects the pumped oil and fills the cavity between the two rear bearings. When the rear housing has the correct amount of oil in it the excess runs out the round hole near the bottom by the speedometer gear. If you use a high temperature grease to hold the 13 bearings in place the 3 oil passages stay plugged with grease until the grease melts and the oil starts to flow. High temp grease or real stringy grease keeps the rear bearings dry until it melts.

I have two friends that bought new Broncos in 1972 and 1973. They have never removed the driveshaft on either when towing. Both are on their second 302's. I bought a spare Dana 20 to find out how they got away with it. Conclusion both never worked on or had someone rebuild their Dana 20 so they never had someone pack the 13 bearings with high temperature grease. I am not saying do not take off your driveshaft when towing. Do what the book says and you will be happier. If the rear driveshaft is not turning the D20 is not getting any oil or at least enough to lube the D20 lubed properly.

 

[Viperwolf1]

Are the rear output assemblies interchangeable?

Yes but there may be a difference in the speedo drive gear tooth count. If both gears are the same color and plastic they will have the same tooth count. If one or both are steel gears it's difficult to tell the tooth count. I guess if after the swap your speedo suddenly reads 20% fast or slow you'll know.

 

[mrdrnac]

If you plan on using grease to hold the 13 bearings in place use petroleum jelly instead. The 13 bearings seem to serve as part of an oil pump to get oil to the bearings in the rear housing. The 3 1/8" dia holes in the rear of the cavity for the bearings are actually a part of the "oil pump" for the rear bearings. The holes are angled at about 45 degrees so oil is sprayed on the face of the rear housing when rear shaft is rotated at driving speed. The rear housing has two holes in the face to serve as oil passages. The triangular hole at the top collects the pumped oil and fills the cavity between the two rear bearings. When the rear housing has the correct amount of oil in it the excess runs out the round hole near the bottom by the speedometer gear. If you use a high temperature grease to hold the 13 bearings in place the 3 oil passages stay plugged with grease until the grease melts and the oil starts to flow. High temp grease or real stringy grease keeps the rear bearings dry until it melts.

I have two friends that bought new Broncos in 1972 and 1973. They have never removed the driveshaft on either when towing. Both are on their second 302's. I bought a spare Dana 20 to find out how they got away with it. Conclusion both never worked on or had someone rebuild their Dana 20 so they never had someone pack the 13 bearings with high temperature grease. I am not saying do not take off your driveshaft when towing. Do what the book says and you will be happier. If the rear driveshaft is not turning the D20 is not getting any oil or at least enough to lube the D20 lubed properly.

Has anyone used Assemblee Goo for the needle bearings? Wonder if it melts quick enough?