Question: Differential Clutch Packs

[ashy22]

Hello Guys,

I've got a 1971 454 Coupe. I now need lots of advice please

My differential clutch pack needs changing out. Differential stamp no ABW048E2

I know this because the last mechanic to look at it had to fabricate something to get it to work (This was in South Africa when I took it over there 15 years ago). Yes it's been all over the world with me - lol

He took some plates from another car and made it work. He did say that it wouldn't last long.

I've had it garaged for the last 10 years, only to take it out and around the block every other month or so.

Anyway I have found new interest in getting it back on the road in a good roadworthy condition. I want to do most if not all myself.

Here's what needs doing.

1. New exhaust - done - just fitted a dual chambered system.

2. New diff clutch plates - next job to be done.

3. Repair leaking brake calipers on both front corners

4. Replace all weather seals

5. Remove all interior and replace center console parts and new carpet.

6. replace all vacuum hosing for lights

7. Tidy engine bay and replace things like master cylinder cover (new chrome etc...)

8. Replace lap seat belts (i am sure that they are illegal over here now!)

Picture of car and exhaust below

Thanks in advance

 

[GTR1999]

Hello Guys,

I've got a 1971 454 Coupe. I now need lots of advice please

My differential clutch pack needs changing out. Differential stamp no ABW048E2

I know this because the last mechanic to look at it had to fabricate something to get it to work (This was in South Africa when I took it over there 15 years ago). Yes it's been all over the world with me - lol

He took some plates from another car and made it work. He did say that it wouldn't last long.

I've had it garaged for the last 10 years, only to take it out and around the block every other month or so.

Anyway I have found new interest in getting it back on the road in a good roadworthy condition. I want to do most if not all myself.

Here's what needs doing.

1. New exhaust - done - just fitted a dual chambered system.

2. New diff clutch plates - next job to be done.

3. Repair leaking brake calipers on both front corners

4. Replace all weather seals

5. Remove all interior and replace center console parts and new carpet.

6. replace all vacuum hosing for lights

7. Tidy engine bay and replace things like master cylinder cover (new chrome etc...)

8. Replace lap seat belts (i am sure that they are illegal over here now!)

Picture of car and exhaust below

Thanks in advance

Nice looking vette. Cool that you kept with you all over the world too and that you plan on rebuilding it.

For the posi clutches the 71 came with what I coined as Snow Flake clutches. They were an attempt to eliminate posi chatter but didn't work only made them weaker and under abuse would break.
You need to use solid steels, no fiber coated, and it is best to tune them as Tom shows in his You Tube video. You can do it, I have coached many guys in the process. If you need help with parts or procedure just let me know.

Keep your original MC it has a value. Same with the seat belts.

Good luck

 

[GTR1999]

I saw you asked about the posi on your other thread so I figured I would answer here.

First here is part one on posi tuning. Takes a little getting use to but you can do it. I made a machine but for years did it by hand.

Tom's Eaton Posi Tune-Up Tutorial (Part One) - YouTube

You have to disassemble the diff to get to the posi clutches. Before you do this witness mark the bearing caps and then check the lash and pattern of your present setup. Take pictures to have reference on. If you are going this deep into the diff then you should figure on rebuilding it completely, yes you could just get to the clutches and replace them but that is your call. Me, I would go through it and that why you need to know where the gears are set to so you get them back when you are done.

There is a fair amount of detail on this job and I have written plenty of threads on it over the years. Some may still be here if you do a search or just search on digital corvettes, I have all updated threads there now.

I'm walking a guy in Germany through it now, once he gets the parts I sent him he will be right in the middle of it.

 

[ashy22]

I saw you asked about the posi on your other thread so I figured I would answer here.

First here is part one on posi tuning. Takes a little getting use to but you can do it. I made a machine but for years did it by hand.

Tom's Eaton Posi Tune-Up Tutorial (Part One) - YouTube

You have to disassemble the diff to get to the posi clutches. Before you do this witness mark the bearing caps and then check the lash and pattern of your present setup. Take pictures to have reference on. If you are going this deep into the diff then you should figure on rebuilding it completely, yes you could just get to the clutches and replace them but that is your call. Me, I would go through it and that why you need to know where the gears are set to so you get them back when you are done.

There is a fair amount of detail on this job and I have written plenty of threads on it over the years. Some may still be here if you do a search or just search on digital corvettes, I have all updated threads there now.

I'm walking a guy in Germany through it now, once he gets the parts I sent him he will be right in the middle of it.

Sorry about the crossed threads before - my mistake.

Just watched the youtube videos. Very interesting and Tom makes it look easy!

I just remembered that there was a fluid leak coming from my vettes diff as well (not sure exactly where from - I will check this weekend).

Maybe best to give it a proper overhaul, even maybe put 4.11/1 ratio gears in instead of the 3.70/1 which are in now (according to the stamp info on the housing).

I prefer acceleration to top speed.

So firstly I need to remove the whole diff from the car.

Ashy22

 

[GTR1999]

Yes you need to remove it and check it. Oil leaks typically are from the pinion seal or side seals but can also be from a bad cover gasket, cracked cover, blown out holes from too long bolts, overfilled and blowing out the vent, or a combination of several of these.

The video only shows the tuning part, before you even start that you need to polish the case. I haven't seen one yet that was polished as I do them. You can look on the other forums but they require a lot more then just the windows edges. Then you must have quality parts to start with, then you get into tuning. There are a few things to look for when doing too, look over both of those videos. Keep in mind Tom is tuning a 30 spline posi which uses real "C" clips, the stock 17 spline axles use a snap ring about 060" thick.

If you have 370 GM gears, then you have a 3 series case and the only 411 gear set to fit that is Tom's. The others will require a 4 series posi case. You can also get a 433 or 456 set to fit too.

Good luck
Gary

 

[ashy22]

Thanks GTR1999

Quote : "Oil leaks typically are from the pinion seal or side seals"

It looks to me like its leaking from the front of the diff where the prop shaft drive enters.

Pinion seal (Hey - i'm learning!) looks like it may have gone.

Didn't get much time to really give it a good looking over this weekend just gone. I will check it again.

I have watched a few of the Youtube videos by Tom. Very interesting indeed.

What is meant by "3rd member" ?

Also checked out your very comprehensive post on the Digital site. Very good. I will go through that one again one night this week.

Thanks for now.

Ashy22

 

[GTR1999]

Thanks GTR1999

Quote : "Oil leaks typically are from the pinion seal or side seals"

It looks to me like its leaking from the front of the diff where the prop shaft drive enters.

Pinion seal (Hey - i'm learning!) looks like it may have gone.

Didn't get much time to really give it a good looking over this weekend just gone. I will check it again.

I have watched a few of the Youtube videos by Tom. Very interesting indeed.

What is meant by "3rd member" ?

Also checked out your very comprehensive post on the Digital site. Very good. I will go through that one again one night this week.

Thanks for now.

Ashy22

Be sure to use a quality sealant on the pinion yoke splines. I use Permatex Permashield now