Transmission/transfer case noise? (1 Viewer)

[stlcruiser]

I have a 94 TLC with the A442 transmission. When the truck is warm (after driving at least 10 miles), and I have the transmission in gear and my foot on the brake, I hear a "chirping" sound, like a squeeking bearing. When I put the truck in park or neutral or let my foot off the brake, the noise stops. The noise is also present in reverse, but not present when the transmission is cold.

Any ideas as what this might be?

Thanks in advance

Steve
94' 105,000

 

[cruiserdan]

Steve,

  Does the sound oscilate? How loud is it? Does it change pitch in 1st gear position vs drive position?  I believe you are hearing the transmission oil pump. I have the same thing in mine. I have heard it for a long time. I hear it mostly when I have the transmission in 1st gear. It goes away as the engine rpm goes up. The noise is difficult to hear with the windows rolled up. I can hear it with the driver's window open, vehicle stopped, hot. It has a sort of a "swish" to it(for lack of a better description). Does that sound like what you are hearing?  If so, I have been assured by a factory FTS(field technical specialist) friend of mine that it does not pose a problem. I have 109,000 miles on mine and I,ve been hearing it for at least 5 years or so. Knock on wood, my trans functions perfectly.

  My .02...........Dan

 

[stlcruiser]

Thanks for the reply. I will get a more complete description tonight. You are correct in that you can only hear it with the window open and no other background noise.

 

[bkuerbis]

Could anyone else describe what a noisy transmission oil pump sounds like? My '91 with 194K makes a knocking noise upon starting up which dissipates as the engine warms to operating temp. The noise seems to come from the back of the engine, down low. The noise only happens in drive or reverse and it speeds up as the RPMs go up. I've been trying to pinpoint it with a dowel rod with no luck so far. Diffs, transfer, tranny and oil have all been changed recently and d-shafts have been lubed. If it is a transmission oil pump, should I be worried?

Thanks.

Brenden