FAB9 rear end with Strange 3rd member : car seems heavier when backing up in reverse.

[kamaro]

I got a '71 Firebird with a full suspension kit from Chassisworks, the rear end is a FAB9 housing with Strange 3rd member using OEM FoMoCo 3.60 gears. The rear is setup fine and quiet, except that I feel its heavier when going into reverse!, even when the car is on jack stands and I try to rotate the wheels by hand its much easier to rotate in forward!, I replaced the gears, bearings, tried different pinion shims with no success. Is it normal for a 9 in rear to act like that?. Its harder to the point that sometimes the engine would stall if I don't slip the clutch enough. Let me know what do you think before I throw away the 9 in and return back to the old trusty GM 10 bolts!

[oleyeller]

Do you have a park brake system on it? Could be a problem there.

[kamaro]

Do you have a park brake system on it? Could be a problem there.

Yeah I do have it hooked and its working fine, I'll try slacking it a bit and see if that makes any differece.

[lobudget]

I'm guessing you have disc brakes but I've seen drum brake cars behave as described. One I worked on was caused by a loose shoe guide anchor pin.

[btmatt]

i have the same setup in my camaro and to be honest i have not noticed a difference. If you are comparing it to a GM rear, the ford pinion is mounted lower on the ring gear possibly contributing to more drag. I just don't know how noticeable it would be.