Have an '86 244 DL with a 4spd/OD transmission (m46). 234,600+ miles. Within the last month the transmission has developed a "whine" in 3rd gear that increases in pitch with engine speed. The "whine" is most pronounced at 3,000 rpm or about 45mph and can be heard at distances of up to several feet from the vehicle. If I disengage the clutch at speed, silence. The gearbox is also completely silent in 1st, 2nd, 4th and OD.

The factory clutch was replaced at ~150,000 miles. ATF has been drained and replaced at regular 4-5 year intervals, but otherwise the gearbox has never been serviced. OD was "rebuilt" about three years ago.

Should I start shopping for a new-used M46? Can I rebuild the existing gearbox?

Your help is much appreciated.

Thnx,

Rich.

>>>ATF has been drained and replaced at regular 4-5 year intervals,

Does that mean that the fluid hasn't be changed in the past 5 years?

I'd do a fluid flush first. Might cost you $15 (or less) and 45 minutes.
If it doesn't solve the problem, you aren't out much.

">>>ATF has been drained and replaced at regular 4-5 year intervals,

Does that mean that the fluid hasn't be changed in the past 5 years?

I'd do a fluid flush first. Might cost you $15 (or less) and 45 minutes.
If it doesn't solve the problem, you aren't out much."

Thanks for your response, Dick. I've drained and replaced the fluid (not sure if this constitutes a 'flush') twice since this problem raised its ugly lil' head, and it hasn't really made a difference. The transmission is noticeably quieter for a few days after the fluid change, but within a week or so the whine is back stronger (louder) than ever.

I read a post in the archives about a failing input shaft bearing, and the noise that the author described sounds an awful lot like what I'm hearing. But wouldn't a bad/marginal input shaft bearing make noise in all of the gears?

Thanks again,

Rich.

are you sure in not the center support bearing on the drive shaft?...Mr. Tool
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Mr. Tool