Any Transmission Experts?

[2000RX300]

My RX300 has a 4-speed automatic transmission. About once a day, for about a week now, I hear a buzzing sound around the time it's about to shift into 4th gear. The sound only last about a second. There is no jerking or feeling like the transmission is slipping. It always shifts smoothly but I obviously have concerns. I’ve always done a “Drain & Fill” on the transmission every summer. That’s more often than the manual says but it’s cheap and easy to remember that way plus if seems to keep the fluid clean. Hoping it would help, I did another drain & fill two nights ago. The fluid looked clean and it didn't stop the noise… I do not know of any trusted transmission shops around here. Any ideas on what might be going on? I really need to keep her running for a few more years. Thanks, Bob

 

[GearheadTool]

It sounds like some sort of servo if its a buzz that happens at a regular interval. Now.. What kind of servo, etc, i dont know.. And it may not be. But......... Perhaps... A servo.. Seems consistent.....

 

[hypervish]

I've never heard a sound like that before. Try posting over on CL to see if anyone else has any clues. But, as far as I can recall we haven't had anyone experience this.

EDIT: Are you sure it's from the transmission and it only comes when it shifts into 4th? It could be a coincidence and the buzzing is really from a mode servo for the HVAC.

 

[Texan4Life]

probably normal....

on a side note, crysler trans are also well known for the buzzzzz-click noise. its more of a if you don't hear it you should be worried. It is mostly noticed at drive thrus since your window is down and you can have an echo effect off of the building.

 

[morris]

by NO stretch am a transmission expert. here is some info i got from this site. i have the auto-zone 2210 filter in my dakota. Here is good external fluid filter. NOTE the sizes
1. go to auto-zone. get 2210, its called a power steering filter, but it is for transs to. it is for 3/8 tubing. by (magna-fine) be sure to use high pressure hose. Reff:http://www.magnafilter.com.au/magna-fine.html
2. for other sizes wix 58964 5/16 tube size reff:http://www.wixfilters.com/filterlookup/transmissionfilter.asp

 

[GearheadTool]

FWIW, my Stepdad had a 1995 Ford Freestar (?) with a whine that was audible and annoying, but worked perfectly.

If it were me, Id have brought it to a trans place to get DIAGNOSED.