What to look for with used 8.75s?

[bakerhillpins]

So the 69 has a 489 case with 3.91 SG unit in it and it whines. I want to fix the 3.91s some year and will get to that but in the short term I want to move to a 3.23 SG unit as was OE on the car and makes for easier cruising. I have found a few local to me on craigslist.

I see quite a few of them and wonder if there is anything to look for when buying one used? Is even worth it to buy a used unit?

[John_Kunkel]

I am of the opinion that there's no way to tell by looking if a rear end will whine. I've seen some gears with really nice looking wear patterns that sang like a banshee.

[bakerhillpins]

So if I want to have 2 pumpkins laying around I should buy what I want but keep the cost down and just roll the dice if it squeaks. If it doesn't then fine otherwise shell out for new gears.

[Chryco Psycho]

really it is a crapshoot , I do not believe anyone is making new 3.23gearsets though , as for the suregrip , if it is cone with 2 spider gears it is probably beat , I looked at 4 suregrips one day , I told him I would buy all for if I could take them apart & they were OK , the cones were worn & bottomed out in all 4 , I did not buy 1
the 4 spider gear clutch type are better , the clutches can be replaced

[green69rt]

So the 69 has a 489 case with 3.91 SG unit in it and it whines. I want to fix the 3.91s some year and will get to that but in the short term I want to move to a 3.23 SG unit as was OE on the car and makes for easier cruising. I have found a few local to me on craigslist.

I see quite a few of them and wonder if there is anything to look for when buying one used? Is even worth it to buy a used unit?

And not all 489s are equal, different dimensions for a,b,e bodies so make sure you get the right one.

[Chryco Psycho]

Are you sure , I have swapped from A,B,C & E , there are 2 different Yolk sizes for he driveshaft but a conversion U joint handles that  

[Dino]

Bryan, my 3.55 open gears looked a bit worn when I pulled them, not done for but normal wear for an old car.  Yet they were dead silent.  My open 2.96 gear looks brand new and came out of a grocery getter.  It howls under load...

Yep, you'll have to gamble.  Good news is those suckers are easily resold and it is by no means a fact that they would make noise in someone else's car.  These things are haunted I tells ya!

[bakerhillpins]

Are you sure , I have swapped from A,B,C & E , there are 2 differ Yolk sizes for he driveshaft but a conversion U joint handles that 

Yea, that's what I though as well.

Crap shoot it is. I found a 3.23 SG unit near my brother in laws for $250. I will have to call and see if it's clutch or cone. I recall you could rebuild the cone type but you had to send it to a machine shop where they cut out the seat and put in a shim with new cones?

Ill have to search on here so I make sure I can recognize cone/clutch.  Would you expect a clutch unit in a 489 case? I thought when they moved to the 489 that they also moved to cone type units and that occurred during the 68 model year. Any confirm or deny on those thoughts?

[green69rt]

Are you sure , I have swapped from A,B,C & E , there are 2 differ Yolk sizes for he driveshaft but a conversion U joint handles that 

This link takes you to a list of all the sizes and dimensions.
http://www.moparts.org/Tech/Archive/rearsusp/1.html

[green69rt]

Found a post with better info.

http://www.dodgecharger.com/forum/index.php/topic,58935.msg657606.html#msg657606

[BSB67]

Found a post with better info.

http://www.dodgecharger.com/forum/index.php/topic,58935.msg657606.html#msg657606

??

I don't think they are talking about rear axle housings

[green69rt]

Found a post with better info.

http://www.dodgecharger.com/forum/index.php/topic,58935.msg657606.html#msg657606

??

I don't think they are talking about rear axle housings

Just reread the thread.  Looks like it's about the rear end guts, not the whole case.  Sorry.

[Cooter]

Is even worth it to buy a used unit?

Did you win the lotto last night? If not, then leave the used units to someone else's pocketbook because it's a gamble at best.

[bakerhillpins]

Is even worth it to buy a used unit?

Did you win the lotto last night? If not, then leave the used units to someone else's pocketbook because it's a gamble at best.

Yep, that seems to be the consensus. However, if I want 2 units then I guess I have to get the 2nd somewhere and as long as I go in thinking it will not work out then I guess I will not be surprised.

I do not believe anyone is making new 3.23gearsets though

A quick google found a few recent discussions in other Mopar forums saying that they are made. 
http://www.forabodiesonly.com/mopar/showthread.php?t=129610

[RIDGERACER383]

My 2.76 gears in my 68 were shot and I put the 3rd member out of a 1979 dodge pickup in it with 3.55 gears..worked great and I was able to use my drive shaft.a direct bolt in.I also used my 68 axles.

[Chryco Psycho]

Are you sure , I have swapped from A,B,C & E , there are 2 differ Yolk sizes for he driveshaft but a conversion U joint handles that  

Yea, that's what I though as well.

Crap shoot it is. I found a 3.23 SG unit near my brother in laws for $250. I will have to call and see if it's clutch or cone. I recall you could rebuild the cone type but you had to send it to a machine shop where they cut out the seat and put in a shim with new cones?

Ill have to search on here so I make sure I can recognize cone/clutch.  Would you expect a clutch unit in a 489 case? I thought when they moved to the 489 that they also moved to cone type units and that occurred during the 68 model year. Any confirm or deny on those thoughts?

True 742 had the clutch & 489 switched to cone but it has been 40 years so a lot of clutch types are in the 489 carriers now .
It is also true that the gears designed for 741 , 742 & 489 gear sets will not fit in different carriers , the only exception is the 742 gears  will bolt into the 489 carrier  with a special conversion rear brg on the pinion

[bakerhillpins]

True 742 had the clutch & 489 switched to cone but it has been 40 years so a lot of clutch types are in the 489 carriers now .
It is also true that the gears designed for 741 , 742 & 489 gear sets will not fit in different carriers , the only exception is the 742 gears  will bolt into the 489 carrier  with a special conversion rear brg on the pinion

Because the 742 pinion shaft is slightly bigger IIRC.

[John_Kunkel]

I do not believe anyone is making new 3.23gearsets though

New 3.23's are available for the 489 housing.

http://www.nitro-gear.com/ring-pinions/

[resq302]

You can also have the sure grip changed out from the cone type to the clutch type set up.  When I had my third member rebuilt, I had also picked up a 742 casing and the place that rebuilt it said the sure grips could be swapped out. 

[Chryco Psycho]

I do not believe anyone is making new 3.23gearsets though

New 3.23's are available for the 489 housing.

http://www.nitro-gear.com/ring-pinions/

good to know 

[Just 6T9 CHGR]

If you are looking for rear end parts Dr. Diff (Cass Eslick) is the go to guy.  Great prices & an all around nice guy that knows his stuff.  Heck he FULLY warrantied an aftermarket Nitro brand clutch type sure-grip unit 3 years after I bought it!  I had numerous problems with it (sent it back to Cass to be rebuilt 2x)  third time I had enough.  he offered to give me ALL my money back & I stepped up to an Auburn unit.  Made in the USA pays off all the time

http://www.doctordiff.com/