Transmission/Differential Whining

[soldier989]

Hey guys! I bought a 1977 Spider 124 yesterday that I believe I got a great deal on. Only things that seem wrong with it is the top and something in the drivetrain. I have searched for others having the same problem I am, and could not find anything on it, so I apologize if this is something that has been previously addressed. The issue at hand:

First off, I have a 5 speed. When in 2nd or 3rd, around 20-25mph a terrible fairly deep whining noise appears to be coming from under the backseat. I could only imagine it to be the differential. When on the freeway going around 70mph and at 4k rpm its less deep but still fairly loud. Ive only has this awesome vehicle for a day now, and have not gotten into it at all, but my father and I think if we adjust the backlash this would go away. Now when accelerating and driving its smooth and doesnt feel bad, just the noise. Any suggestions?

Also, Ive read the stock oil pressure guage is pretty terrible, at idle and when driving around lower speeds (20-30) the guage reads 0. When on the freeway going 70 the guage reads around I would imagine 20-30psi. When the engine/oil is cold the guage reads at about 20-30psi, I can only imagine this because the oil is cold and thicker. This seems a bit alarming, but when reading documentation from the previous owner, they got an oil change at Jiffy Lube, who put 5w-30 in it. This was a complete surprise to me as I think this engine would require a heavier oil. Im going to change it before I drive it anymore, what oil and weight is recommended?

Any input on this would be very greatful from a Fiat newbie.

[So Cal Mark]

A couple of issues here; noise could be pinion bearings or axle bearings. It's common to find loose pinion nuts, so definitely check that out. If the noise changes from load to float and decel, then it's pinion related. If it stays the same under those conditions, think axle bearings.

As for engine oil, your temperature range is quite different than we have in Calif but in the winter I'd use 10/30 and in the summer 20/50 or 30w. We have a pretty long thread about oil use, and there is a serious issue with motor oil and the lack of zinc which lubricates the camshaft. If you use the search function, it shouldn't be hard to find.

[soldier989]

Thanks again for your input! Yes, the noise does change from accel, coast, and engine braking. I will definately look into that. Should I be very cautious about driving it then? My Dads shop is about 30 miles from me, and I would rather not tow it there, but if need be I would work on it in my garage. As for the Oil, I will definately look for the forum!

Thanks

[So Cal Mark]

before I drove it 30 miles I'd make sure the diff has oil in it

[pope]

My bet is that he has chipped teeth on the pinion gear. I've had two gears like that over my life and the sound is about the same as discribed. I wonder if the person who sold it to you knew this and hid the fact.

[soldier989]

The guy I bought it from put 1,000 miles on it in 3 years, he knew something was up with it as did I when I test drove it. He had it checked and serviced numerous times and put 2k into engine. He went to a local import shop (Hughes Automotive) who did all the work, they checked the transmission and said it is sound (Have paperwork). Though, I doubt they checked the rear end. I will check the oil in the diff. though i already drove 30+ miles to get it home . You never know the true story when buying a used vehicle.

I hope its nothing terrible, but Im sure its fixable regardless. Thank you guys for informing me what it seems to
be. My question is, if it were the pinion gears, wouldnt it happen all the time when accelerating? I definately could be wrong. I think I will make a video and post it of what it sounds like while I drive it. That would probably help diagnose the issue.

[pope]

One thing you can do is to drain a little of the differential oil and check if there are metal shavings in the oil. You can do this at home and will go a long way towards determining things.
Good Luck and let us know

[mbouse]

only costs a couple of bucks to completely drain the diff and replace with fresh gear oil to the proper level. as you drain it, inspect for shavings and chunks.

if the noise disappears, you are in luck. if not, you prolly have something more wrong than you are personally able to remedy?

[soldier989]

Im sure that will be the first thing we check. Im going to Michigan this weekend, so It will have to wait another week. Unless I get my butt out of bed early enough. Thanks for the input!

[mbouse]

where in michigan? ummm.....that is where I am. Are you sure you wanna do that?

[soldier989]

I hope you dont think Im referring to taking the FIAT up there, thats way out of the question. I would be riding in the less comfortable Cougar. I actually doubt Im going now. Think Im going to visit my grandma in Cleveland.

My girlfriend is from South Lyon which is right next to Ann Arbor. Shes going to visit for her dads bday.

[mbouse]

about 1 1/2 hours east of me.

have a great time.

[soldier989]

Here's a video of me driving the car, and you can hear the whining noise coming from the rear. Its kinda hard shifting, steering a car with no power steering, and recording a video are the same time. Thank youtube for destroying the quality of the movie. Ive talked to Jon, Im gonna be swingin by his place sometime to help diagnose the problem.

http://www.youtube.com/watch?v=I1x31D0mwlM