High Pitch Sound in R,2,3

[Ludigdrums]

I get this weird high pitched sound when I put the trans in Reverse, 2nd or 3rd. Not in Drive however! It's very strange, and I do not know where to begin to check this out. The tranny fluid looks good and is full. It doesn't sound like a belt squeal, and it's not crazy loud...but loud enough for me to hear and be concerned about.

Any thoughts?!

Thanks!

- Jeremy

 

[Ludigdrums]

Anyone got any thoughts on this one?!
Thanks!

- Jeremy

 

[brusso]

Is the car moving, in these gears, or is it staionary? If squealing at a stop, may be in tranny. If when car is moving, may be in drive train or speedo cable. Although, the tranny wouldn't be completely ruled out.

 

[22229stingray81]

Ludigdrums,

This question has been posted before, every year or so it pops back up. I posted it about 2 or 3 years ago. The general consensus between '81 owners is that this noise is normal with the TH-350. I've had it since the day I bought my vette, (back in '99) and no one can really explain it. Regardless of which, do not worry, it is normal. Though if it is still bothering you, please investigate and share anything you find. Hope I brought some ease to your mind.

-Tatortot

 

[Ludigdrums]

The car is for the most part stationary...it's hard to really hear whether or not it happens while moving...but I suspect that it does at slow speeds. And, yes, it only happens in those gears, just sitting there stopped. In drive, there is no sound.

22229stingray81, thanks for the peace of mind...my only concern is that I just recently noticed it. So, whenever I hear a new sound, my ears perk up and I start questioning things. I will continue to search for and answer, and will let you know if anything ever comes from it.

Thanks again!

- Jeremy

 

[22229stingray81]

Tell me about being scared, the first time I heard it I thought I needed a new transmission!! But 40,000 miles later and shes still going strong. I do not think it makes the sound when you are in motion, only when you are idleing. Hope this helps, good luck!

-Tatortot

 

[black_81_vette]

The buzzing you guys are hearing is the pump in the transmission actually its the dicharge port that was added in 81 because the use of the lock up clutch in the convertor (new for 81) anyway its nothing to get excited about, but in 82 the problem was dealt with by use of updated parts.And if im not mistaken the corvette went with a 700 r4 trans as the only auto option and trans for that matter, but the th 350 was still avaliable in trucks after 81.

 

[Ludigdrums]

Wow, that's real interesting. You really know your stuff! Thanks!

I don't have the computer anymore in my 81...how does that affect the convertor lock up function? My tranny seems to do two semi-strange things:

One being at part throttle, sometimes it doesn't know whether or not it wants to downshift...like it can't make up it's mind.

The second being that the shifts are real soft, and I think because of that, when it does shift, it kinda revs high and seems like I'm giving it more gas than I am, and then settles back down. This happens pretty quickly, like within a couple of seconds, but it's still noticable enough to raise question.

Other than that though, the tranny feels tight, no slips or anything...I'm think these symptoms are due to the lack of computer w/a lock-up convertor?

Any more thoughts?

Thanks as always!

- Jeremy

 

[black_81_vette]

actually what is happening there is the lock up clutch in the convertor has gone or is going south ,the ecm effects part of the lock up but not all .as the valve body and input shaft and pump are different in a lock up vs non lock up tansmission. the previous year had a switch in the valve body and had a vacume switch tied into the brake switch to controll convertor lock up.Those cars and or trucks hunted between lock up and non lock between 30 35 mph or any kind of incline lots of customers complaned about it too.The best bet is to take the trans out and replace the pump,input shart,and convertor with non lockup items and dont forget to fluch the cooler lines or any trash in there will thwart any work youve done.

 

[black_81_vette]

BTW the flare up in rpms is caused by for the most part by the direct clutch seal getting hard. does it act up shifting cold or after its been driven?