11" drum scraping backing plate after conversion; axle sits deeper after diff swap. What's up?

[cudak888]

Long-term update: Went to a car show on Saturday. Haven't put many miles on the car since March due to never-ending instrument cluster issues, since resolved.

That said, I started getting an intermittent driveline vibration that worked itself way right up the steering column during the last 3/4 of my trip in. Was worse on the way back. I was guessing flexplate or driveshaft, but I stopped in a parking lot on the way, and was able to butt-shove the rear of the car sideways 1/4" inch in each direction.

Jacked her up this afternoon and found 1/4" of play at each axle shaft. Aiming to swap the rear end back to the original 2.76:1 next weekend to get the car back up and running and give the 3.23 an inspection.

No idea if I galled up the bearings in the process either. Also wondering - given the gutlessness of the 360, especially at anything over 50mph - whether it'd make more long-term sense to leave the 2.76:1 in the rear and swap the 904 for an A999 with the lower first and second gear ratios.

-Kurt

 

[mopar 3 B]

If not running green bearings just adjust axle side play and see what happens. If any damage has been done its done.

 

[cudak888]

If not running green bearings just adjust axle side play and see what happens. If any damage has been done its done.

Go back to my post #28 - perhaps read the whole thread too so you'll be familiar with the problem. You'll see the adjuster is already backed in quite a bit. I don't have another quarter inch to spare.

In short - I already adjusted sideplay long ago...the "what" already happened.

-Kurt

 

[mopar 3 B]

Go back to my post #28 - perhaps read the whole thread too so you'll be familiar with the problem. You'll see the adjuster is already backed in quite a bit. I don't have another quarter inch to spare.

In short - I already adjusted sideplay long ago...the "what" already happened.

-Kurt

The what really happened is I do not see where the original problem was solved and now there is a bigger problem.

 

[cudak888]

The what really happened is I do not see where the original problem was solved and now there is a bigger problem.

The original problem was thought to have been alleviated (not solved) by spinning the adjuster in a bit deeper. I can't spin it in any further as you suggested.

It's past band-aid levels; it's time to pull it to find out what's really going on.

-Kurt

 

[cudak888]

Well, my questions are answered. The 3.23 chunk's thrust block is just that - a block of steel with a hole in it. Have no idea if it's factory Mopar for another application or someone's experiment. Surprised the axles butted up at all.

Bears no resemblance to the block in the 2.76 unit.

3.23:

2.76:

Wish I had known what the correct one looked like in the first place before I went through all this effort.

Was lucky though - caught a bad u-joint in the driveshaft while swapping the 2.76 unit back in, and had both ends taken care of. And honestly, if I could get my hands on an A999, the wider gear spacing over the 904 would probably sooth my dislike of the 2.76 without ruining highway capability.

-Kurt

 

[mopar 3 B]

Surprise surprise!
It will be a long time before you forget that one.

 

[cudak888]

Surprise surprise!
It will be a long time before you forget that one.

True, but I'm even more curious where the "wrong" thrust block came from.

Probably going to use this as an opportunity to learn a bit more about fixing a diff...

-Kurt

 

[Cranky]

Not factory for sure.....would like to see what it looks like out of the unit....

 

[mopar 3 B]

The square block I have taken out of other Mopar units. The later pictures is the one I do not ever remember seeing. Any idea how how the block is held on the pin?

 

[cudak888]

Not factory for sure.....would like to see what it looks like out of the unit....

It wobbles a bit, but I think it's simply a square tube with a slightly oversized round hole through it - nothing fancier.

The square block I have taken out of other Mopar units. The later pictures is the one I do not ever remember seeing. Any idea how how the block is held on the pin?

Really? What year rear ends and cases? Haven't seen any other pictures other than those that match the latter type on the 2.76 unit.

-Kurt

 

[mopar 3 B]

I have diffs & housings from 57 to 68 could have been out of any of them. Anyway it got removed during a diff or housing swap.

 

[cudak888]

I have diffs & housings from 57 to 68 could have been out of any of them. Anyway it got removed during a diff or housing swap.

I'm 99.9% positive the 741-case 2.76:1 unit I pulled out is original to the '68 Satellite, so it stands to reason the round thrust block is the correct one for that era. From what I could tell, it had never been removed until I pulled it.

Might look into some of the '50s Mopar forums to see if I can dig up any more info on these square blocks.

-Kurt

 

[Cranky]

I've never worked on anything older than 1966 and have never seen a square block like that and I've been doing rear end work since the early 80's. The spiders (small gears) need a cross shaft to ride on while the side gears ride in a fit in the carrier. The block needs to have something for the spiders to ride on and hold them in place. Rotate the ring gear 90* one way or the other and you should see the face of a pin that goes through the unit. Some units (newer ones) have a roll pin go retain the cross shaft. I have a 741 open sitting here that has what looks like a large screw driver slot on one end of the cross shaft and no roll pin. Maybe it's only the 741's that are built that way? Don't know since I haven't messed with the 41 unit much at all.

 

[cudak888]

I've never worked on anything older than 1966 and have never seen a square block like that and I've been doing rear end work since the early 80's. The spiders (small gears) need a cross shaft to ride on while the side gears ride in a fit in the carrier. The block needs to have something for the spiders to ride on and hold them in place. Rotate the ring gear 90* one way or the other and you should see the face of a pin that goes through the unit. Some units (newer ones) have a roll pin go retain the cross shaft. I have a 741 open sitting here that has what looks like a large screw driver slot on one end of the cross shaft and no roll pin. Maybe it's only the 741's that are built that way? Don't know since I haven't messed with the 41 unit much at all.

Cross shaft is there under the block. Can it be removed (via that screw or pin) along with its respective spiders without pulling the carrier itself? If so, can do...

-Kurt

 

[Cranky]

Should be able to do that....

 

[69Bee]

The 2:76 thrust block is the normal piece I am used to seeing. While the other square block could be a factory piece (any PN's# on it), the easiest way to fix this is to use the 3:23 unit with "Green" axle bearing set. If you had the thrust washers, they would have to come out anyway. Since they are in effect already missing, just use the Green set, and off you go, no adjustment necessary...

 

[cudak888]

Should be able to do that....

Will chuck the snout in the vise and find out...

The 2:76 thrust block is the normal piece I am used to seeing. While the other square block could be a factory piece (any PN's# on it), the easiest way to fix this is to use the 3:23 unit with "Green" axle bearing set. If you had the thrust washers, they would have to come out anyway. Since they are in effect already missing, just use the Green set, and off you go, no adjustment necessary...

Well, the car is back together with the 2.76:1 and it's working fine, so that's the extent of what I'm going to do at the rear axle.

Regardless, I'm not a fan of the green bearings. Lots of work to change something that isn't broken yet to begin with (somehow, my tapered bearings survived the 3.23), and, in my opinion, inferior - especially for everyday street use.

Changing the thrust block seems to be relatively easy by comparison, according to Cranky. Should find out this afternoon. Don't have one to replace it with, but I can pull it.

-Kurt

 

[cudak888]

Something tells me that removing the pinion rod isn't as easy as it seemed, eh, Cranky?

Gotta assess whether I really want to fool with this thing or just flip it for a few other parts I'm short on.

 

[Kernel Sanders]

Before removing your carrier, measure the backlash and record it.

remove carrier

remove ring gear (left hand threads)

punch out roll pin holding the cross shaft

push out cross shaft which will allow you to remove that weird thrust block and replace with correct one.

push cross shaft back in and replace roll pin

replace ring gear and torque to spec (I cant remember off the top of my head)

Carrier back in, adjusting backlash to what they were and torque caps (again cant remember spec off the top of my head)

all done