FD3S Diff Whining on Decel???
 

Hey Guys,

I went to the track last week and ran my car twice. After the 2nd run I started to hear a whine coming from the back of the car. After i got home I jacked up the car and put it in gear. Everything looks good and dry but a loud whine when the diff is slowing down. So nothing on accel but a whine on decel.

Does this mean my Diff is going bad?
Any way to fix this? if not which diff should i go with? KAAZ?

I have a 94 FD, stock twins, 12psi , Power FC, intake, FMIC, Full exhaust.
First run was 12.7 then second run was a 12.4

Thanks

You should also check the driveshaft.

FD3S Diff Whining on Decel???
 

Thanks for the Tip.... I haven't checked the Driveshaft or U Joint yet. I did some research and they say that most likely it'll be a bad ring and pinion gear.

I was looking for a new one and found 4.3 and 4.7 gears. Its my weekend car and I never go past 140 mph so I was thinking of buying the 4.7 gears. It'll probably put me at 160 ish for my top speed but probably take off .5 sec off my 1/4 mile time.

Anyone tried the 4.3 or 4.7 gears? Any pros or cons with them? Loud Noise from gears, worse gas mileage, or too low of a gear????

Any input will help... Thanks

Before replacing the diff, start with the easy stuff if you haven't yet. When was the last time you changed the diff fluid? What fluid are you using? Are you using any additives?

BTW, what tires are you using on the drag strip?

I changed the diff fluid about 3 months ago. I put in Royal Purple Max Gear Oil 75w140. No Additives. I have BF Goodrich g-Force T/A Drag Radial.

I haven't had the chance to look at the car yet. I doubt that the UJoints are bad. I put a long screwdriver to the diff and the other end to my ear. I checked several points around the diff and I can hear it the loudest on the diff itself.

I will check the tranny and the Driveshaft next time.

Thanks for the help

Ah. Go ahead now and just invest in the Kaaz or a TII diff.

Mine whines on decal also. I have a Kaaz Diff with new fluid. My u joints are good, and so is my ring and pinion. So I dont know what to think.

I was thinking maybe the pinion bearing could be going bad??? Cuz on decel it could be putting upward or downward pressure on the bearing... creating the noise.

When you changed out your LSD, did you change out all of the bearings?
Im just wondering if that could be the problem....

Also.... 1 way, 1.5, or 2 way LSD? did you notice a big difference from stock?

Thanks

Yes I changed the bearing too so I dont know what else it could be. Not to worried, my exhaust is louder then it anyway.

1.5 way Kaaz. Hell yes! I broke my stock diff on my first pass at the drags. The kaaz has been holding up fine to 8k drops. There is clunk on slow turns but I dont care.