trans problem
 

My brother-in-law has a early 90's S10 blazer with an auto trans . I do not know if it is a 200 or 700 but it is an overdrive . It is making a growling noise in reverse and 1st . It shifts fine , doesnt seem to be slipping , etc . Just the growl in low and reverse . Any ideas what he is looking at ?
Frank

Re: trans problem
 

Its a 700 (2004r's never went into trucks).

Is it in 1st gear in drive or D1?

In LOW (D1) and reverse the line pressure is boosted and the L/R clutch applied. In drive or overdrive, 1st gear uses only the forward clutch. If the noise is not there in 1st gear in drive, there are a couple of possibities. Occasionally these trans will develop an oscillation in the pressure valve circuit, whwich will 'buzz' under higher pressures. The pump could be tired and complaining about having to make extra pressure for the L/R boost. A L/R seal could be leaking (although usually that would have other issues).