'96 D1 transmission whine

[bsa_m21]

For the past two months I've had a distinct whine coming from the transmission of my 96 D1. It's not overly loud, quite high pitched, and happens only while moving and not coasting, stopped or in park. e.g. If I let off the gas the whine goes away. A slight pressure on the gas pedal and it's back - even a quick blip that doesn't increase my speed - brings it on for a few seconds. It gets louder under load, goes away when coasting.

Tranny fluid was just changed 5k ago and is still full. It was suggested to me that the transfer case oil might be low, so I checked it yesterday. It was full but a bit dirty, so I replaced it. No change to the whining.

I don't think it's the water pump or it would do it when I rev the engine while parked.
I do have a slight oil leak from the main seal on the front cover and the oil pressure light stays on for a few seconds on cold startup. Neither of these could cause the whine IMHO.

Any guru's out there that might have an idea what might be causing the noise?

Thanks,

 

[sir]

It's the transfer case, don't worry about it. Thicker oil will quieten it a little.

 

[German Gruner]

Whine that goes away depending on gas pedal pressure means axial play by hipoidal gears.
Transfer case and diffs can whine. You should check all connections to driveshafts in order to find unusual or excessive axial play.

Regards

 

[jastutte]

My '96 did the same. I changed the transfer case oil to a good synthetic and the whine mostly disappeared.

of course, the noise from the cheap muffler may also have helped.

 

[Johnaddalia]

Try greasing the u joint on the front driveshaft. The transfer cases do have a wine that changes pitch depending on conditions.