Sorry, but I installed one freakin Ford part on my car and it has a problem. graemlins/angry.gif It goes in and out of posi mode...sometimes I'll be burnen both of em while takin off and shift to second and all of the sudden I have single track. What gives? Its a 3.50 4 spyder, 31 spline, posi all stock. Thanks Scott

This one might be better off in the drivetrain forum (more responses!).

Are you sure you don't have a locker?

Joe

a locker type rear would typically stay locked until you burp the throttle to unlock it, or it unloads (when you ermove the throttle pedal from the floor).

Im sure its not a locker. Do you think im supposed to use some sort of additive with the oil? I just have 90w 115 Valvoline gear lube in there now, I only used Valvoline cause it was "available". :rolleyes: BTW what does an additive actually do?

I know GM REQUIRES an additive as does Chrysler I believe...unsure on the FORDs, just be sure your gear lube is not synthetic. Typically the additive is a friction additive, considering oil is used as a lubricant it almost makes sense to me...I still bet the clutches are worn or the spring pressure is weak in the posi

Ford requires an additive in for their posi units also. The additive is a friction modifier - allows the clutches to slip a little when going around turns. Most [probably all] rear gear lubes have a friction modifier in them already. If your Ford 9" is slipping on straitline runs, it needs a rebuild. New clutches and springs are relatively cheap and fairly easy to do. I have done several before. Just pull the center section, remove the posi carrier {with ring gear attached}, disassemble the carrier and install the new parts. It is a very simple rebuild. Make sure to measure and mark the preload for the carrier bearings before disassembly. Fords use a threaded adjustment preload. Put the unit back together with the exact same number of turns of the adjusters and you should have no problems. A lot of the 9" posi rears have come out of trucks and often see a fair amount of abuse, even though they physically hold up, they still wear out.

Ok thanks looks like I'll be pulling it out soon! When it goes back together I will make sure the lube has an aditive also.