Rear Diff Leak

[87mj]

Hi The diff in my '71 has developed a nice little leak I believe around the diff cover.  I thought this would be an easy repair job.  But with the mustache bar and cross member covering the cover, it looks like minor surgery to replace the gasket.  I have three questions:
1 - Do I need to remove the mustache bar in order to remove the rear diff cover? 

2 - Do I need to drop the entire diff

3 - Is this as big of a PITA as it looks????

Thanks in advance. 
Gary

Edited September 4, 2017 by 87mj

[ramsesosirus]

I've never done this job, because I read about how hard it is...

I believe it can be done without dropping the diff, but you need a system to get new oil in the cover (hoses and whatnot).

I've also read that both the drain and fill plugs can sometimes be "non-removable" due to their location, almost impossible to get enough torque on them.  

Might be easier to drop it all and do a bunch of work all at once (if needed)

[sweatybetty]

On 8/6/2017 at 4:18 PM, 87mj said:

Hi The diff in my '71 has developed a nice little leak I believe around the diff cover.  I thought this would be an easy repair job.  But with the mustache bar and cross member covering the cover, it looks like minor surgery to replace the gasket.  I have three questions:
1 - Do I need to replace the mustache bar in order to remove the rear diff cover? 

2 - Do I need to drop the entire diff

3 - Is this as big of a PITA as it looks????

Thanks in advance. 
Gary

it isnt that hard, but it is a PITA   loosen the bolts for the driveshaft (leave the shaft in the trans to keep the oil in) and axles, remove the strap, front mount and the 2 nuts on the back cover. slide the diff toward the front of the car until the 2 studs clear, and then lower the diff down

1-no

2- it will make life easier.

3-see above

 

after doing this 3-4 times, it isnt that bad

Edited August 14, 2017 by sweatybetty

[gnosez]

I have swapped diffs in under 2 hrs but it helps that I do it regularly.

I have a custom attachment for my large jack that allows me to hold the diff and half shafts without it falling off.

Driveshaft bolts, mustache bar end bolts (take it down with the diff), half shaft bolts (at the wheels), diff cross member and carrier bracket bolts. drop diff, remove mustache bar, drain diff if you haven't already, remove cover, clean up everything, replace gasket and cover, fill diff, attach mustache bar, lift into position, add bolts.

[Zed Head]

You might also be able to lower the diff just far enough to get the mustache bar off without removing the axles and propeller shaft.  Just a guess.

Before you get carried away make sure that it's not just oil vapor blowing out of the vent, or leaking half shaft seals.  Might make the decision easier.  

If you do decide to take it all the way out, I'd remove the mustache bar and everything as a sub-assembly, like they show in the FSM.  It's heavier and bulkier, but simpler overall.

Edit - as gnosez says, dropping the mustache bar with it is the way to go.

Edited August 15, 2017 by Zed Head

[87mj]

Thanks everyone for the help.