wasp

started it every once in a while during winter,runs fine just like last year, but now when its idling it makes a wierd whining noise .... almost like a blower whine but more abrasive...it seems to be coming from back of motor underneath where tourque converter is...only does it when idling give it gas it goes away and like i said it runs fine........any one seen this b4?

Vader

Wasp,

Would you characterize the sound as more of a buzz than a whine? The pressure regulator in the transmission can create a "buzz" at low engine speeds, and that usually disappears just above idle.

If you feel that may be your situation, I'd suggest getting the engine and transmission fully warmed (by driving) and see if the noise persists. It was a VERY common problem in the older TH700-R4s before the valve body and pump upgrade around 1987 or so. It used to happen either in PARK/NEUTRAL or in gear at lower RPMs.

Just a possibility.

wasp

yep more of a buzz.........level 10 completely rebuilt my tranny too......got maybe 6000 miles on it after rebuild tops........is this something to be comcerned about? or does it just make noise when its cold? didnt do it till this year been driving it for 3 years ,summer only

wasp

btw its a 91 700r4

MrNova

I have a similiar sound in my car, kinda like a cellphone vibrating on a table noise, or a muffled vacume cleaner. When its in park I dont hear it, but when I'm driving with foot off gas I hear it. If I push gas EXTREMELY lightly, the pitch of the buzz raises, and once I press the gas lightly, so lightly the tach doesnt move, the buzz goes away. I have an automatic (700r4) 1988 GTA. I just got it so I can't say it makes it during the summer as well.

MrNova

hey, found this at http://www.f-body.org/oldfaq/html/faq/ch3.html
------------------------------------------------------------------------------------
Q: What's that buzzing/grinding noise at low RPMs?

A: It could be related to this technical service bulletin:

Bulletin #: 277142
Publish Date: 10/92

Models: 1984-1993 Firebirds w/ Hydra-matric 4L60/700R4 Trannys

Condition: buzzing noise from tranny at idle (more so when in reverse)

Cause: pressure regulator valve oscillating due to oil pressure
instability at lower idle RPM

Correction: a new pressure reg. valve has been made to improve oil
pressure stability at lower RPM (part #8684048)
------------------------------------------------------------------------------------
So does this mean there is a problem with the valve, or can I just ignore the buzzing?

wasp

more input please?

Vader

Wasp,

If you want to verify the transmision oil presure syndrome, use a mechanics' stethoscope on the transmission oil cooler line at the radiator to isolate the sound. If that's the source of the noise, you can probably safely ignore it. I had the same issue on an '88 Astro with 700-R4 and it went fine for 170,000 miles (until it got traded for a new one).

To be on the safe side, you should probably service the transmission filter and change oil if you haven't done so in teh last 30,000 miles. It may not solve the noise problem, but you'll get a good look at the oil, pan, and filter. If you are ambitious it might be a good time to install the replacement regulator.

wasp

oh man i have an external cooler with fan,,an aluminum trans pan, and i change fluid and filter about every 5,000 since i beat on it.............from what your saying i guess it will be ok

wasp

so you can get to the regulator