I just bought a new 1970 mustang fast back with a 302 and a tremac tranny. Its has a posi rear and has power assist steering. When i turn either way with the mustang it gives me a wierd jerky feeling. The only thing that i can relate this to is using a locked 4 wheel drive on drive pavement. When you turn a locked 4 wheel it makes the same type of thing. I am not sure what a posi rear end does so i was wondering if that could be the problem. I guess it could also be the steering gear box. The steering is really loose so i think i will have to replace that anyway. Please lt me know the difference between a posi and regular and any suggestions you may have.

 

does it make any sound like rubbing? I know that feeling of 4x4 on pavement!

how far do you have to turn the wheel before that happens (lane change or u turns only?)

does it leak power steering fluid?

could it be brake issue? Jack the front up and turn the steering wheel side to side watch for anything weird, lock full left and then attempt to turn both road wheels by hand, do the same for full lock right.

Is the jerking feeling from the front or back? Did he say the posi track was limited slip or did he say Detroit locker?

the idea of posi track is to get equal power to both wheels under any condition. Limited slip allowfor some slip burnouts will usually have one stripe a bit longer than the other butits best for street performance as it allows for smoothturns and U turns as the inside wheel must spin slower than the outside wheel and it allows for it.

A locker basically remove the differential from the equation. It will give full power to both wheelsunder any situation.Burnouts produce equal length stripes but the lockerwill make a popping soundwhen making U turns and is generally rougher on tiers as there is no slip since one tire cant spin at a different rate when making a turn.

The generic setup isno posi itsupplies equal power only if both tires have equal traction. If one tire spins the tire that is spinningtakes all the power and the tire with traction gets no power. It produces only one stripe in a burnout. Rear tires must be rotated frequently as one will wear out far faster than the other.

Gun

 

sounds like you have a locker, or the posi is malfunctioning

i have a detroit locker in mine.... in parking lots i'm on the clutch a lot, b/c the locker wants to stall the engine out , and there's an audible "clicking" noise in turns until the wind noise knocks it down

sure you don't have a locker? I have a 4x4 too, and i would definitely compare the locker to 4x4 on dry surface

 

Does the "jerky feeling" come from your hands or your butt? Have you inspected the front end components? What kind of shape are they in?

How much play is in the steering wheel before the tires move?

What does the front tire wear pattern look like?

Inspect the front end with a fine tooth comb. I lost a good friend in high school because of a 1970 notchback that would outrun the Word of God but he spent no money on the front end.

Long story short, 110+mph, slight rise in the road, airborne, front end dissentigrates on landing, 40 feet of chain link fence pipe through the grill, firewall, Joe, front seat, back seat, tail panel and ending with uprooting a 25ft tall Florida cabbage palm tree.

A quick way to tell if you have a trac-loc or an open rear end is to raise the rear tires off of the ground. Rotate a tire forward. If the other tire rotates in the same direction, it is a traction lock/posi. If not, then it is open.

 

Im not sure which posi system i have as i bought the car from a man that was in jail and needed the cash fast. It was a buy pretty much as is for really cheap (2000). I have a feeling that it isnt locked because when i pulled out of the parking spot (it was snowy) it felt like one tire was spinning more than another. I could very well be wrong with that because the guy was in the proces ofpretty much decking it out to drag race. As for when it does. It does it on regulr turning ad even more on sharp turning but not on lane changes. I cant do anyof the test that you mentioned for a while because I am haveing shoulder surgery tommarrow morning but i will try to remember to do it for in amonth or 2 when i am out of the sling

Thanks For the Help

 

i'm assuming the car in your sig is the car you're talking about? if so , it looks like a coupe not a fastback?

as to how it drives - mine doesn't cause any difficulty on the road just changing lanes, its the sharper turns and tight turns in parking lots that really cause it to happen

good luck on the shoulder

 

nope... My signature is my OTHER mustang. That one is in quite a few pieces right now. I bought this one bc it is drivable and was a really good deal. This one IS a fastback. I dont have any pictures up yet but hopefully i willhave som soon

 

ahh, cool - nice to have one to drive and one to wrench... I don't have the space for that (yet)

 

i dotn have the space too... I am only 18 but i am content with the car sitting in my parents driveway for now. It was sitting in parking lot before i bought it as for my other car... It is sitting inan old horse stall in an old barn that i renovated so i could have electricity in it and have it walled off from the rest of the barn. You gotta use what you have