This might be a stupid question, but what the heck I'll ask it anyway. I have a 8 3/4 rear end. I also have a 489 case, nothing in it just the case. I also have gears that are for the 489 case. Here is my question is the actual differential part(sure grip, or open type) is that also case specific, like 489's have to stay with 489's, 741's with 741's etc. Any help would be appreciated!
Differential Question
- Thread starter IL duster
- Start date
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OldVart
Well-Known Member
Any complete center section will fit into any of the 741, 742 or 489 cases. If you try to mix parts for the center section itself, i.e. gears, bearings, pinion, then you will run into problems since each center section is different. Oh, and there's no such thing as a stupid question. 
Thanks for the help. This is what I was trying to do. I have a set of 4.10's in the car right now. That's cool for going to the dragstrip and around town. But I would also at some point like to take the car on a trip, like a caravan to the Mopar Nats or something. So I looked into one of those Gear Vendors overdrive things. And althought they are super nice, they come with a super high price tag! Then I thought I would just do another center section. That way I can just leave the 4.10's in for around town, but then when I want to take it on the road, then I can switch in some highway gears. I had the original center section that came out of the car, but I cannot find the stupid pinion anywhere!!! That differential is a open type out of a 741 case. I have another 489 case and some highway gears 2.76's that are from a 489 case but no center differential section. So I was going to use the 741's differential part with the 489 case and the 489 highway gears, that way i would have a cheap center section that didn't cost loads of money. So what do you think? From what you said it should work, just wanting to give more details as to what i am doing. Thanks again, this board is great!
Dan
Dan
dusterdon
Well-Known Member
In the olden days (80"s) we could go and find highway pigs 2.94 2.76 etc for $40-$50 any day of the week. But I guess that the standard going rate for a 3.91 3.55 or 4.10 was around $100. Look around you could probably find a decent highway pig for under $100. Good to keep around. Its hard for me to pay the going rate for a good 4.10 today. But if you want to play, ya gotta pay!
don
don
Yeah I looked at getting a whole 3rd member assembly to. They used to be just laying around my local salvage yard. People took them out trying to find a sure grip and once they saw it was an open differential and highway gears they just left it sitting. I went back to that salvage yard a week ago and could not find one 8 3/4 in the whole place. They used to have at least 40-50 mopars in the back, no they are all gone. I found 3 cars i would consider old mopars. None of them had anything I could use on them. I can't find anything local as this was my main source of parts in the past. Now I'm left with ebay and paying higher prices. Any help would be appreciated. I just want to make sure that my idea will work before buying all the stuff to do it. Thanks!
Dan
Dan
Il Duster,
As far as I know, (which isn't much sometimes), you can't do what you are trying. All of the parts from the center section have to be the same. ie: case, gears, bearings and carrier.
Any case and guts will fit any axel though, except for the very early stuff, pre 62 I think.
dusterdon has the right plan. Pick up a center section out of any 8 3/4 and swap it out when you want. If your just going to use it for highway cruise's, then a one legger will do fine and you should be able to get one for $50 to $100.
Jack
As far as I know, (which isn't much sometimes), you can't do what you are trying. All of the parts from the center section have to be the same. ie: case, gears, bearings and carrier.
Any case and guts will fit any axel though, except for the very early stuff, pre 62 I think.
dusterdon has the right plan. Pick up a center section out of any 8 3/4 and swap it out when you want. If your just going to use it for highway cruise's, then a one legger will do fine and you should be able to get one for $50 to $100.
Jack
If anybody knows of where I can get one for 50-100 let me know. I don't know where i can get one that cheap anymore, since my local salvage yards don't have the older mopar stuff anymore. Ebay was my only other option and the ones I saw went for a lot more than that. I'm close to St. Louis, MO, so if anyone knows something please let me know. Thanks!
Dan
Dan
Keep your eyes on the for sale sections of the different boards. They come up every so often.
I got mine off of one of the members here.
Jack
p.s. cdwmotorsports has some 489's for $75 right now.
I got mine off of one of the members here.
Jack
p.s. cdwmotorsports has some 489's for $75 right now.
ta3834bbl
68 cuda 383 project
Yes, you can do what you want to do. You can use any case with any diff unit ( ie, suregrip or open ) but you must use the correct bearings for the diff and you have to use 489 case gears with a 489 case / or 741 gears in a 741 case / or 742 gears in a 742 case. I would still just pick up a used pig complete when you can.
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