differential removal

**Bob R.** · January 5, 2018, 02:27 PM

Re: differential removal

I think you need to remove the cross member and drop the entire unit you are almost there anyways. There are only two bolts holding the cross member in but if the sombreros have been there for 50 years they might not want to come off. Only loosen the bolts don't remove them or replace them with longer bolts so the assembly won't come flying off and you will have to get the longest pry bar you have to break them free. Look out when decide to come off. You should inspect the bushings and determine if they need to be replaced while you have it all apart.

**Walter R.** · January 5, 2018, 07:08 PM

Re: differential removal

I am dropping cross member with differential cover as I don't see any other way to do it. I left the two bolts in to catch cross member,after backing out about half way. I didn't know if there is something else holding it in place that I am missing. So I should put pry bar between cross member and frame and apply more force? Didn't want to go to this step before making sure there wasn't something else holding it in place.

**Gary R.** · January 5, 2018, 07:12 PM

Re: differential removal

Walter
I don't know if you are the same person who asked a similar question on another forum or not but I am concerned with your situation, I hope you have the diff supported as the only thing holding it in the car is the front bracket. The cover and cross member are only being held in by pressure on the tapered cones, if those loosen up it will come down. It is much easier and safer to remove the diff as a complete unit. Not knowing what type of repairs you are planning on it would still be better to remove it. I would be happy to offer any advice & support to help you with the repair. Just be careful.

Gary

**Walter R.** · January 5, 2018, 08:10 PM

Re: differential removal

That was not me. I am trying to make repair without removing complete differential if possible. If it can not be done than I will remove complete unit. Differential is supported properly. When I jack up car at rear the drivers side yoke comes out of the differential about 1/4" exposing the race of the yoke. The passenger side does not do this. This has been like this for years. Never had a problem with rear end so probably should leave well enough alone. I've been wanting to repair for some time and am finally getting around to this effort. I'm sure there is some type of clip that holds the yoke in place that was either never installed at the factory or in laying in differential case. After exposing inside of unit if I cannot install clip with unit in place I will remove a probably deliver to professional for repair. One other note when turning car sometimes you fell like something slides at rear of car and has been this way for 50 years and I suspect this could be the source of the issue. Not a significant issue and something only I would be aware of from driving over the years and it was there when the previous owner drove the car.

**Gary R.** · January 5, 2018, 08:54 PM

Re: differential removal

Walter
Clearly the axle is missing the snap ring or it is worn out and .250 would be very worn. So most likely the snap ring is off. I still recommend remove the diff and for good reason.

1- once out you can mount it on an engine stand if you have one or can borrow one. This will allow you to access the axles though the center of the posi case.
2- look at the ends of the axles, they should have a chamfer on them and the snap ring groove is .187-.200" from the axle face. If there is .250 wear on them the groove would be gone and the axle would have crashed into the housing and seal.
3- If the snap ring is not seen it might be thrown forward and could have ended up in oil channel or chewed up in the spiders. GM snap rings were 065 -066" thick and should freely slide around the groove once installed with a little pressure.
4- you will need 90* snap ring pliers to install/remove the clips. I have a set of fixed tip pliers I got out of trade school 40 years ago that work great.
5- I recommend you replace the axle seals and recommend the CR/SKF brand. Pack the spring with grease and grease the ID. I use RTV on the OD regardless of the green coating.
6- I use ultra gray on both sides of the cover gasket as well.
7- A stock posi setup with the springs and good axles will probably have 020" endplay in the axles but it will vary from posi setup to setup. I tune the posi and set the endplay to 005-010.

Now some guys remove the snap ring to allow the axles to float when using upper strut rods but I always use snap rings or c-clips with the 12 bolt and super10 diff's.

Here is a link to one of my old threads with pictures that should help you.

http://www.digitalcorvettes.com/forums/showthread.php?t=77713

**Timothy B.** · January 6, 2018, 10:57 AM

Re: differential removal

Originally posted by Walter Rowe (49838)

That was not me. I am trying to make repair without removing complete differential if possible. If it can not be done than I will remove complete unit. Differential is supported properly. When I jack up car at rear the drivers side yoke comes out of the differential about 1/4" exposing the race of the yoke. The passenger side does not do this. This has been like this for years. Never had a problem with rear end so probably should leave well enough alone. I've been wanting to repair for some time and am finally getting around to this effort. I'm sure there is some type of clip that holds the yoke in place that was either never installed at the factory or in laying in differential case. After exposing inside of unit if I cannot install clip with unit in place I will remove a probably deliver to professional for repair. One other note when turning car sometimes you fell like something slides at rear of car and has been this way for 50 years and I suspect this could be the source of the issue. Not a significant issue and something only I would be aware of from driving over the years and it was there when the previous owner drove the car.

I may be having a brain fart but if you remove the crossmember and rear cover what's holding the rear pumpkin, that front mount is not strong enough to hang the heavy pumpkin. Take the driveshaft off and remove the front snubber mount and remove the complete assembly, it's way easier in the long run.

I once helped remove the pumpkin and left the cover and crossmember in place but you have to be very careful installing so no leak at the cover gasket.

**Walter R.** · January 6, 2018, 04:27 PM

Re: differential removal

I had a jack under for support but I decided to pull the whole unit to replace seals as Gary suggested. I have removed differential but still have not gotten the cross member out. I got the passenger side free and have soaked the driver side with lubricant an will hopefully get that side free tomorrow. Amazing how stuck they were. I put quite a bit of pressure with a 5' pinch bar. Big relief when I got the one side to break free.

**Gary R.** · January 6, 2018, 05:06 PM

Re: differential removal

You can probably get a larger puller on it to pop it off. Good idea to have the longer bolts in place so it doesn't drop out on you.

Your diff should have the 1" sq window in it, if not it has been replaced at some point.

**Richard G.** · January 7, 2018, 02:27 AM

Re: differential removal

I have had good luck removing the cross-member using hydraulics and a duck-billed ram. Always with longer bolts in the sombrero bushings. I vividly remember removing my first one. I couldn't believe the grip the rubber sombreros had. A wrecking bar, the type used in home remodeling is another option. Most automotive bars are just too short to overcome the polident grip of the bushings.

**Chris B.** · January 7, 2018, 10:35 AM

Re: differential removal

I had better luck popping mine off with a two jaw puller. I drilled a little starter hole in the head of the sombrero bolt so the point of the puller bolt would stay in place.

**Ed S.** · January 7, 2018, 10:56 AM

Re: differential removal

Walter - if you use a pry bar of any length to separate the sombrero bushing from it mount be sure to apply DOWNWARD pressure only. DO not insert the tip of the bar and pull up on it. If it releases or the bar slips the bar will go into the fiberglass of your wheel well opening and damage it. Always press down on the bar. Tip - I would press down as best I could and moved it some - then had a second person squirt in some lubricant - WD40 worked for me. Let it sit a day, did it again and again. Each day it went down a bit farther. On the 4th day a slight nudge with the bar and it almost slid off smoothly.

**Walter R.** · January 8, 2018, 10:49 AM

Re: differential removal

I am applying a little lubricant each day. I have gotten the differential out and have time to get cross member down. With one side loose I know it can be done so I will be patient with other side.

differential removal

differential removal

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