8.8" Axle

[Shawneebear93]

So I wanna get a 8.8" Traction-Lock rear axle to go along with my studded snow tires for the winter driving. I'd like it with 3.73's, but would use a stock (3.08 or 3.27) for now.
Question: Is that gonna mess up my speedo/tach, I know ship points may change but will both meters be off? How can I fix this?
I have the 85 MPH speedo.

 

[techdbw]

Changing rear gears will change your speedo. your speedo will read low, not sure how much.
If it were me I would wait until I got the gears in that 8.8. With 3.08 gears, that car won't be able to get out of it's own way.
There is a handy chart to tell you what speedo gear to use with each rearend. http://ddperformance.com/speedo_gear_chart.htm. you can find it here.

 

[Ray III]

I've been meaning to ask but does anyone know if 4 banger rear brakes will bolt right up to the 8.8 rearend? Its just the differential unit thats different isnt it?

 

[85 Coupe 5.0]

Correct. If it's an 8.8 out of a Mustang with 4-lug drum brakes, everything is identical, from drums to shoes, to all the hardware.

The only difference is the differential carrier, carrier bearings, ring and pinion, spider gears, pinion bearings and pinion flange. And the cover.

The axles, axle bearings and seals are the same.

 

[Shawneebear93]

So basically, a direct swap.
I was reading Stinger's page and figured it couldn't be that much work! Although Stinger had a rear disc conversion, too.
Man, I wanna buy his car when he's done with it! LoL

 

[Bearded Forever]

Is the pinion flange where the driveshaft connects? If so they are the same.

 

[Ray III]

ahhhh the driveshaft I forgot I'm going to have to get that son of a bitch off. I had to take the motor out of my car and i wanted the trans with it so I had a wrench on there and was slugging away at it and those bolts aren't going anywhere. So I just yanked the transmission off the driveshaft. Maybe I should get my junkyard rearend with shaft attached

 

[85 Coupe 5.0]

Is the pinion flange where the driveshaft connects? If so they are the same.

I'm pretty sure they are not, the 8.8" pinion splines are larger. They appear very much the same, but the 8.8" splines are larger. I recently was repairing an 8.8" pinion, (someone hammered on the part that the nut threads on to remove it from the housing) and mushroomed the threaded end of the pinion. I was going to use a 7.5" flange to check how far down it actually went on the splines, but it's too small in the splined area to fit on the pinion.

Besides, if the diameter of the splines on the 7.5" yoke are the same as the diameter of the splines on the 8.8" it would be only as strong as the 7.5" axle because the splined area would be just as weak as the 7.5".

EDIT: Crovax- if you meant that the bolt pattern for the driveshaft is the same you are correct, but the splines are different and the flanges are not interchangeable.

 

[Ray III]

Ok what about the differential housing. I was taking a nap under the car and dreaming of donuts in the snow and started fiddling with teh speedo gear and then I realize if this car has different final reduction its gonna screw my speedo up, and I don't really need extra work yanking out a perfectly good rearend and swapping brakes and everything over.

SO if all is the same except internal parts and the cover, then I will just buy trac-lok parts to rebuild mine. Cool?

 

[ka0tyk]

7.5" and 8.8" pinion spline is the same, the driveshafts are interchangable. The only difference is the size of the pinion and ring gear. The 8.8" brakes do NOT line up on a 2.3L equipped car. Reason being that the brake line is on the wrong side of the car. Just remove the brake lines from your 7.5" rear end and replace them onto the 8.8" and zip tie them all on there so they dont go anywhere. Thats all I had to do in my 8.8" swap...

If you REALLY want a good upgrade see if you can get your hands on a Lincoln Mark VIII rear end... then you'll have an 8.8" rear end with disc brakes. you'll have to find some 5 lug rims, but you'll be biiiig pimpin then!

 

[ka0tyk]

SO if all is the same except internal parts and the cover, then I will just buy trac-lok parts to rebuild mine. Cool?

you CAN buy a 7.5" track-lock for your car but you can pickup a full 8.8" rear end and gears for probably cheaper. And you'll have a rear end that your 2.3 could never break...

 

[Ray III]

the gears are worn out and like I said I'd rather not buy more worn out gears that are likely the wrong ratio, and add mine to the scrap heap.

8.8" and 7.5" differential housings... are they the same or no?

 

[Asha'man]

Housings? No.

Could always just swap a Turbocoupe rear in, that way you'd get 8.8, either 3.45's or 3.73's depending on the tranny, trak-lok, and discs, and still be able to run your four-lug wheels.

Ash

 

[Ray III]

I'll just get 7.5" gears and a trac-lok kit for them, does FORD sell them? how much is it for ring, pinion, bearings, clutch pack, whatever else I need?