I have been having a problem with a noise that is getting worse. It started after I rose the passenger side to replace the fuel pump. When I barley touch the gas pedal while going down the road I get a grinding/whiny noise coming from the back of the car. When I put the car into neutral and coast to a stop, I get a ticking/thump sound. (Almost sounds like the half shaft is loose and hitting something every time it spins) I know it’s not loose I did look at that. My instincts tell me it’s the differential making this noise. Most of the sound I hear sounds like its coming from the middle rear to the right rear. Now this morning I was stopped at a light and tried to go forward and was stuck. The tranny would shift but the car would not move. I had to put the car in reverse and back up about an inch then she went forward. Right now I am moving into a new house so time is very important. I plan on replacing the diff fluid and see how this works. What kind of fluid should I use 80W90 or could I use Red Line Oil 75W90?

O yeah is the filler hole for the rear Diff on the top of the Diff?

Any advice would be great.

Thanks,

John

You are better off taking it to a shop, they have a drip machine to drip lube into the differential, if you dont you will be trying to fill it for about an hour and a half, beleive me I have done it and its a pain in the arse! Just my 2cents.

I think I will raise the car up in the next day or two and take a good look to see what is causing this. When I do this I may just have to switch out diffs. I have an extra on hand. When I do this I will clean it and fill it with some good oil.

To answer your question about the location of the fill port, it is located on the diff cover above and to the right of the drain port.

All you need to fill the diff easily is a little pump that attaches to the top of a typical oil bottle. It has a pickup at one end that fits into the bottle, and a hose on the other end. Using this it only takes a few minutes to fill. I did both the diff and tranny in 10 min. You can get one at any auto parts store for $4-5. Even better would be one that had a crank/pump rather that a vertical piston/pump.

Where is the fill plugs on the transmition and the rear diff located at. I know they are up on top, but where abouts on top?

I have a 4 speed and a R200 Diff. Going to due a big oil and lub change this weekend.

John,

Is it possible the noise you're hearing is the fuel pump. Electric diaphram type fuel pumps make that sort of sound normally. Plus if you are at a complete stop and you here these sounds, it's certainly not coming from the drive systyem as it is at rest when you are stopped.

My old 280zx with a disc brake rear end had a similar problem, it turned out the caliper was seizing. Used to just catch a high spot on the disc when driving and thump a bit, occasionally seizing on and slowing the car right down. Check it's not actually a brake problem while you're at it.

Lift the rear end and chock the front wheels, start the car and put it in gear, see that helps you pinpoint where the noise is coming from, then go from there.

240SX,

I have a new fuel pump. Its alot louder than the hum of that.

May have to raise the rear end up and take a look. Going to change the fluids any way this weekend. Hope I can find it. Got it narrowed down to half-shaft, Rear diff, or tranny.