8.75 swap help

[Jeff Erwin]

The people I am ordering the unit from are asking about a clutch-type limited slip. What are my options, which do I want?

 

[oldkimmer]

Clutch type is a real good unit. That is what u want. Kim

 

[george glover]

71 Dodge Charger 400x6. The previous owner was going to put it on the drag strip back in the late 90's so he put a 4.10 Sure Grip in it, then put it in a warehouse where it sat for many years. I obtained it about 4 years ago. Everything is perfect now except for the 4.10, it has to go. I am going to put a 3.23 set in it by just pulling the existing case and plugging in a different one.

I haven't done this before, so I have some questions. The housing has a large '6' on the side, so does this make it a 489 or a 742, or is it something else? Are the different cases interchangeable? There are a few places where I can order a complete differential, but I have to get it right so the thing fits.

Large yoke? What are the options and how do I tell what I have now?

Spline count? I'm pretty sure these are the splines at the end of the axle that insert into the diff, how do I tell what my axles are other than pulling one and counting?

Dumb questions probably, but I want to make sure what I end up ordering actually fits and works.

number on side of case742-742-489 look up Dr Diffs site for info

 

[Woodsy]

Doesn't hurt. You can download a service manual from link below. You may need to use a 1970 manual the 71 says body service manual. Shows how to set axle end play, you need to do that!
Service Manuals – MyMopar

I have been looking for a service manual for a 68 Charger and note that this link doesn’t have one. Would somebody be able to point me in the direction of one or do I need to use the 69 manual?
Thanks I’m advance.

 

[Fran Blacker]

I have been looking for a service manual for a 68 Charger and note that this link doesn’t have one. Would somebody be able to point me in the direction of one or do I need to use the 69 manual?
Thanks I’m advance.

Try Ebay, Year One or Classic Ind for service Manual. There is very few differences between a 68/69 Chargers they have a 69 Charger SM at that link. Doing an 8.75 3rd change you could use a 1965 to well into the 70's for that.

 

[Woodsy]

Try Ebay, Year One or Classic Ind for service Manual. There is very few differences between a 68/69 Chargers they have a 69 Charger SM at that link. Doing an 8.75 3rd change you could use a 1965 to well into the 70's for that.

Thanks, appreciated

 

[4speed68rt]

If you are just going to do a swap out, and you have a choice of the 3 different carriers, go with what it already has. If it is a 489 go with a 489, 741, 742 etc...Direct swap, no surprises.

 

[Jeff Erwin]

Went with the 489, that’s what’s in there now. Having one built with 3.23 gears.

Pulled the axles, went to disconnect the drive shaft from the pinion on the diff. Removed the two brackets but can’t figure out how to get the drive shaft off the pinion. Any clues?

 

[Don Frelier]

The axle needs to be hanging.
A small prybar to pull the u-joint away from the pinion. A good sized screwdriver usually works well.

You can also just wack it with a soft hammer.

It Will move

 

[Fran Blacker]

Have driveshaft so the cups are horizontal if possible so cups are less likely to fall off.