8-3/4 Sure-Grip Questions

[V8Pacer]

Okay I have some questions. I'll be buying a 8-3/4 sure grip rear axle from a 1973 Chrysler Town & Country in a junkyard on Monday. It was a 440 car. Engine is gone.

First question. From what I understand you can convert an open axle to a sure grip just by swapping in a sure grip 3rd member assembly. Am I correct in assuming this?

Second question. I'm buying the axle but I'm just going to take the third member and leave the axle housing behind. Don't want to deal with storing a complete axle if I don't need to. So should I take anything else off the axle besides the 3rd member assembly?

Third question. I currently have a 1973 Fury with the slant six. I'm not buying this axle for this car, I'm buying it because I plan on buying another 72 or 73 Fury some day. So did all 72-73 V8 Fury's come with a 8-3/4 rear axle? Am I going to have any issues with this 3rd member fitting a 72 fury or a 72-73 fury with a different size V8?

3rd member is the correct terminology? Not carrier case because the carrier is only part of the 3rd member?

I'm paying $200. I'm assuming I shouldn't think twice about paying this much for a 8-3/4 sure grip?

 

[Davea Lux]

1.) All 8.75 third members use the same bolt pattern, so that part of the conversion is simple. Check the spline count on the rear axles, there are several different counts, so you will need axles that match your rear end.
2.) The town and country housing is wider than the standard C Body housing so unless you are planning to buy a wagon at some future date, you do not need the housing for this conversion. (This housing also fits the 1/2 ton P/U) Might want to keep the axles and brake backing plates. The 440 cars have a wider rear brake drum so you will need the backing plates if you plan to make the big brake conversion. The T & C axles are an item you can sell for about $50 each. (axles will fit some 1/2 ton P/U)
3.) '72-73 fury will most likely have a 7.50" or 8.25 rear end with the slant six as will most 318 and some 360 2BBL engines. 360 4BBL, 400 and 440 engines will have the 8.75 rear axle. You should check the build sheet to confirm what rear end came in the car as there was a variety of other options.
4.) Third member is the correct terminology for an 8.75 rear end.
5.) $200 is a fair price for the rear end if it is in usable condition, inspect what you buy as rebuilt units go for as much as $1000. Note that the 400 and 440 engines have the large differential yoke as opposed to the smaller one used on some other applications with the 8.75 rear end.
6.) You will want to leave the 3rd member and axles someplace dry and protected from dirt etc. These parts will go to hell quickly if not properly protected. I usually leave the housing together until I am ready to use the parts.

Dave

Okay I have some questions. I'll be buying a 8-3/4 sure grip rear axle from a 1973 Chrysler Town & Country in a junkyard on Monday. It was a 440 car. Engine is gone.

First question. From what I understand you can convert an open axle to a sure grip just by swapping in a sure grip 3rd member assembly. Am I correct in assuming this?

Second question. I'm buying the axle but I'm just going to take the third member and leave the axle housing behind. Don't want to deal with storing a complete axle if I don't need to. So should I take anything else off the axle besides the 3rd member assembly?

Third question. I currently have a 1973 Fury with the slant six. I'm not buying this axle for this car, I'm buying it because I plan on buying another 72 or 73 Fury some day. So did all 72-73 V8 Fury's come with a 8-3/4 rear axle? Am I going to have any issues with this 3rd member fitting a 72 fury or a 72-73 fury with the different size V8?

3rd member is the correct terminology? Not carrier case because the carrier is only part of the 3rd member?

I'm paying $200. I'm assuming I shouldn't think twice about paying this much for a 8-3/4 sure grip?

 

[CBODY67]

Pre-buying used parts can be a good orientation to have . . . so long as they actually fit your later-intended purchase vehicle. Some things that might be suspected to be "common", can change with the next model year, by observation, or as noted, with particular vehicle equipment.

On a limited-slip rear axle, where the "wear items" would be the clutch discs which make it all work AND be of undetermined wear, your $200 could be a good investment or otherwise. You never know about salvage yard parts. If your future-purchase would be more of a daily-use car, it might be fine. If you're dreaming of a big-inch stroker with 500 horsepower, that $1000.00 reman unit might be best. And . . . that wagon's condition might have been pretty good, but if age has taken it's toll on the fibre-based frictions in that limited-slip unit, you'll end up with a rebuilt unit one way or another.

So, worst case scenario . . . in a few years, you need to liquidate your "chunk", you might probably sell it at a swap meet for more than you paid for it. IF you end up getting a reman unit, be sure to get one from a reputable vendor. You might also check some of the regional rear axle (think "truck") that do Dana or Spicer parts/repairs and see if they might be able to rebuild what you get, hopefully for less than what the musclecar vendors might charge?

As far as the rear yoke goes, I think there might be "conversion u-joints" with two different sizes of caps or possibly using a more appropriate yoke itself? The number of axle splines might be a "deal-killer" though, unless some other internal parts (side gears?) might be changed to accommodate this deal.

Your determination.

CBODY67

 

[70bigblockdodge]

Later sure grips are cone type. Once they wear out they are not rebuildiable easily. You can buy a carrier for your open rear, brand new for 350-450 and a bearing installation set for 85 more and you will have new.
I have gotten burned on used cone type sure grips. Did not work very well in car, seemed just perfect in hand.
$200 is good price regardless. Since your pulling the axles I would save the backing plates and drums if possible, the resto/clone guys need 11x2.5 rear brake pieces.

 

[CBODY67]

On the "non-cone" style of limited slip, I believe you can see the flat clutch friction packs inside of the rear axle differential housing, once the "chunk" is pulled out. Should be a flat plate (on each side) with coil springs holding them apart? These are very rebuildable, usually. There's a special tool to compress the coil springs (usually 4 of them) for disassembly and reassembly of the clutch packs. At least that's how the GM axles tend to be.

CBODY67

 

[70bigblockdodge]

If you see springs on a 8 3/4 it is a cone type. The "good" sure grips with rebuildiable clutches have 4 pinion shaft ends showing, and they are sitting in V shaped saddles. If they are very tight they can be agressive in low traction conditions but great for drag racing.

 

[V8Pacer]

Thanks for all the detailed information. Much appreciated.

Been doing some research in my parts books. Unless I'm mistaken all axle shafts from a 8-3/4 are interchangeable from 1972-1973 C-body wagon & sedan Plymouth Dodge Chrysler as well as Satellite Coronet wagon. (Part # 3432786) Can't be 100% sure on my findings these parts books are hard to interpret.

 

[V8Pacer]

So am I to understand there is no way to determine whether or not a 1973 8-3/4 Sure-Grip rear end is worn by looking at it? I would think that if these Sure-Grip rear ends aren't re-buildable they would be more durable but I'm sure this is wishful thinking.

Based on what you guys are telling me I'll be bringing home the axle shafts, brake backing plates, brake drums and of course the 3rd member.

I'll post pictures when I get this stuff home. Also will post pictures of the car in question in case anybody local needs something off of it.

 

[Davea Lux]

So am I to understand there is no way to determine whether or not a 1973 8-3/4 Sure-Grip rear end is worn by looking at it? I would think that if these Sure-Grip rear ends aren't re-buildable they would be more durable but I'm sure this is wishful thinking.

Based on what you guys are telling me I'll be bringing home the axle shafts, brake backing plates, brake drums and of course the 3rd member.

I'll post pictures when I get this stuff home. Also will post pictures of the car in question in case anybody local needs something off of it.

You can look for the obvious stuff like chipped or rusty gears. The condition of the bearings and clutch packs is tougher without disassembly. Small pieces of clutch material in the bottom of the housing or pieces of clutch material hanging out of the clutch packs is usually an indication of excessive wear. The cone type sure grip is usually serviced as a unit by replacing it.

Dave

 

[Davea Lux]

Thanks for all the detailed information. Much appreciated.

Been doing some research in my parts books. Unless I'm mistaken all axle shafts from a 8-3/4 are interchangeable from 1972-1973 C-body wagon & sedan Plymouth Dodge Chrysler as well as Satellite Coronet wagon. (Part # 3432786) Can't be 100% sure on my findings these parts books are hard to interpret.

View attachment 192126 View attachment 192127

Look at the length of the shaft for all ex wagon=30 5/8", station wagon =31 21/64, lines 2 and 3 first page. They are also a different part number.

Dave

 

[V8Pacer]

Look at the length of the shaft for all ex wagon=30 5/8", station wagon =31 21/64, lines 2 and 3 first page. They are also a different part number.

Dave

"Look at the length of the shaft for all ex wagon=30 5/8"........Look at the top of that page. Your reading column R & W (R=Satellite) (W=Coronet/Charger) So part # 3432830 is for all Satellite-Coronet-Charger except Wagon.

"station wagon =31 21/64, lines 2 and 3 first page. They are also a different part number."........Your reading column R W P D C C C (R=Satellite) (W=Coronet/Charger) (P=C-bodyPlymouth) (D=C-bodyDogde) C=C-bodyChrysler) I interpret this line as Satellite-Coronet Wagon only & All C-bodys 4-door/2-door/wagon. Part # 3432786

These parts books can be very difficult to interpret.

 

[V8Pacer]

You can look for the obvious stuff like chipped or rusty gears. The condition of the bearings and clutch packs is tougher without disassembly. Small pieces of clutch material in the bottom of the housing or pieces of clutch material hanging out of the clutch packs is usually an indication of excessive wear. The cone type sure grip is usually serviced as a unit by replacing it.

Dave

Okay great, I'll Disassemble the axle in its natural position So any clutch material will remain at the bottom and be easy to find.

 

[70bigblockdodge]

It's a steel cone, no clutch material. They are pretty durable the ones I got burned with still worked just not all the time or if you were the least bit turned it would single. Your axle shafts will work with sure grip. The different ones were way back with taped axle shafts (keyed hub held on by a nut). All one piece axles are same, sure grip or open. They do vary from model to model.

 

[V8Pacer]

So as far as removing the axle shafts I just remove the 4 nuts on the brake backing plate and then remove the axle shafts? If need be mount the brake drum on backwards and use that as leverage? (Homemade slide hammer)

 

[70bigblockdodge]

removed the 4 nuts on the brake

5 nuts, if it only has 4 it is not a 8 3/4

 

[Davea Lux]

"Look at the length of the shaft for all ex wagon=30 5/8" Look at the top of that page. Your reading column R & W (R=Satellite) (W=Coronet/Charger) So part # 3432830 is for all Satellite-Coronet-Charger except Wagon.

"station wagon =31 21/64, lines 2 and 3 first page. They are also a different part number." Your reading column R W P D C C C (R=Satellite) (W=Coronet/Charger) (P=C-bodyPlymouth) (D=C-bodyDogde) C=C-bodyChrysler) I interpret this line as Satellite-Coronet Wagon only & All C-bodys 4-door/2-door/wagon. Part # 3432786

These parts books can be very difficult to interpret.

 

[Davea Lux]

www.bigblockmopar.com has an axle chart that is easier to read in the tech section.
You appear to be correct, the Fury used one axle length in '72.

Dave

 

[livininharrow]

any reason you don't take the whole thing home?

 

[Davea Lux]

So as far as removing the axle shafts I just remove the 4 nuts on the brake backing plate and then remove the axle shafts? If need be mount the brake drum on backwards and use that as leverage? (Homemade slide hammer)

It should not be necessary to get too rough with the removal, a crow bar behind the lug flange will usually pop the axle out. If the brake drums are any good, save them, the big ones are hard to find.

Dave

 

[V8Pacer]

www.bigblockmopar.com has an axle chart that is easier to read in the tech section.
You appear to be correct, the Fury used one axle length in '72.

Dave

Thanks Dave, That's a lot easier to read than the parts book. Looks like 1969 C-body wagons had a different length axle than non-wagons.