ok is this a bad ppf or differential bushings? when i step on the gas i notice that the shifter bobs up and down and i hear a vibrating noise at the same time coming from the rear! is this a cracked ppf? or is it worn differential bushings?

 

anyone?

 

could be a few things and definately a cracked ppf. just get the car up on a hoist and actually look to see if theres a crack or if anything else is loose

 

upon visual inspection from underneath i can see any cracks or loose bolts or anything, but the ppf is hard to look at visably, you have to remove the whole catback system, and the downpipe and stuff, anyhow so you guys diffinintly think that its the ppf that has headed south hey

 

I would bet on a cracked PPF. However, removal is simple, largely dependant on your mods... If you have a dp, mp, catback, all you have to do is remove the midpipe, lower the catback (letting it hang from the rear hangers), put a jack under the differential, remove 8 nuts and 1 bolt, and possibly loosen the driveshaft (4 bolts). The PPF slides right out and it will be obvious if it's cracked enough to move the shifter. The removal should take about 20 minutes, properly setup with tools and knowing what to do. It's very simple, and not easy to mess up. I recently was swapping a good PPF between two FDs while waiting on my new one to arrive depending on which car I was driving, it's not that bad... To do the job right, go ahead and replace the 8 nuts while you're at it, just because the manual says so...

Richard

 

What's a PPF?

 

Power Plant Frame- rigidly connects the transmission to the differential to keep the whole drivetrain from torquing and causing excess wear. It started on he miata, but was carried on to the FD if I remember correctly.

Richard

 

The PPF usually cracks right in front of the diff on the bottom. You should be able to see any cracks there without taking anything off the car.

Jeff

 

I agree with turbojeff, that is where I have seen them crack (nearly in two!) you need to take a closer look and if you don't see it, then check to see what's moving (shifter, tranny, PPF, engine, diff, etc) and you will be able to determine exactly where the "pivoting" point is.

 

kinda happens with my shifter also...when ever I give it gas in 3rd gear, the shifter will move up a little and when I let go of the gas, it will go back down. It doesn't really do that in all gears, but most noticable in 3rd.

 

Yeah mine does that too, it kinds of bobs back and forth a few mm if i press/release the gas. I think this is normal but I guess it depends on how much it moves. Does anyone here with a stock car NOT have this?