Drivetrain Weird Aod Transmission Sound

[5.0specialist]

Hello everyone. I have a 1991 automatic mustang gt. I've noticed when the transmission has completely warmed-up, it makes a weird sound just as it is about to shift from 2nd into 3rd gear. It is like a brief squeal sound. Sounds like beeeeez. Doesn't sound like a metallic grinding noise and the transmission does not slip. The fluid also looks and smells good. The fluid level is also okay. I also floored it once and instead of shifting at the factory 4700 rpm shift point (first to second) it shifted at 3500 rpms. The car has 3.73 gears, but I don't think it is suppose to affect full throttle shift points. Other than that, the shifts feel good and not sluggish. I've checked the TV cable and it is set at a point which there is no slack and no tension. I'm going to take the car to a transmission specialist tomorrow, but I would like to hear other opinions also.

Thank you,

Alexi

 

[FoxtrotTangoWhiskey]

Hello everyone. I have a 1991 automatic mustang gt. I've noticed when the transmission has completely warmed-up, it makes a weird sound just as it is about to shift from 2nd into 3rd gear. It is like a brief squeal sound. Sounds like beeeeez. Doesn't sound like a metallic grinding noise and the transmission does not slip. The fluid also looks and smells good. The fluid level is also okay. I also floored it once and instead of shifting at the factory 4700 rpm shift point (first to second) it shifted at 3500 rpms. The car has 3.73 gears, but I don't think it is suppose to affect full throttle shift points. Other than that, the shifts feel good and not sluggish. I've checked the TV cable and it is set at a point which there is no slack and no tension. I'm going to take the car to a transmission specialist tomorrow, but I would like to hear other opinions also.

Thank you,

Alexi

I was looking at SilverFox transmission for a valve body. You are supposed to be able to adjust your shift points in increments of 800RPM but he has it set @5800 for every gear. Also, he has some that have a constant pressure on the TV valve, you can remove the TV cable with this valve body. I heard of the TV valve leaking pressure and it acts like the TV cable is out of adjustment, I am no expert though...

Here is his list of valve bodies but most of them require a 12v wire to the OD hold out function, then he has the ones without wires and they are cheaper. I am looking at the SPT-1CP for about $320.
http://www.silverfoxtrans.com/silverfoxtrans.com/VB_AOD.html

I really dont know what the "squeal" sound is???

 

[FoxtrotTangoWhiskey]

Oh, I hope that it is not your transmission pump going out... Dont let me scare you, I am an entry level mech... I have been known to be right about 80% of the time though... If you have it inspected by a shop they should do a pressure test, which is testing your pump.

I did go to school for automotive service tech and graduated with honors... It does not mean that I am an expert though.

 

[General karthief]

Maybe tires losing grip on the cheap asphalt road your on. Seriously, hard to diagnose on 'paper' take it to a trans shop, they would know. It maybe something as simple as a belt slip but I doubt it, hardly ever simple.

 

[General karthief]

Oh, I hope that it is not your transmission pump going out... Dont let me scare you, I am an entry level mech... I have been known to be right about 80% of the time though... If you have it inspected by a shop they should do a pressure test, which is testing your pump.

I did go to school for automotive service tech and graduated with honors... It does not mean that I am an expert though.

I stayed at a holiday inn once.

 

[FoxtrotTangoWhiskey]

I stayed at a holiday inn once.

Shortly after you lost grip on cheap asphalt?

 

[General karthief]

Shortly after you lost grip on cheap asphalt?

Yes, how did you know?

 

[5.0specialist]

If it was the pump would it be constant and just when it is about to shift into 3rd gear? By the way, it is not tire or belt squeal. It is a unique sound coming from underneath the floor.

 

[5.0specialist]

I was looking at SilverFox transmission for a valve body. You are supposed to be able to adjust your shift points in increments of 800RPM but he has it set @5800 for every gear. Also, he has some that have a constant pressure on the TV valve, you can remove the TV cable with this valve body. I heard of the TV valve leaking pressure and it acts like the TV cable is out of adjustment, I am no expert though...

Here is his list of valve bodies but most of them require a 12v wire to the OD hold out function, then he has the ones without wires and they are cheaper. I am looking at the SPT-1CP for about $320.
http://www.silverfoxtrans.com/silverfoxtrans.com/VB_AOD.html

I really dont know what the "squeal" sound is???

I actually used silverfox's SPT-1 valvebody in my old 93'. That was several years ago (2009) when he charged 190 bucks instead of 275 bucks. lol

 

[5.0specialist]

Oh, I hope that it is not your transmission pump going out... Dont let me scare you, I am an entry level mech... I have been known to be right about 80% of the time though... If you have it inspected by a shop they should do a pressure test, which is testing your pump.

I did go to school for automotive service tech and graduated with honors... It does not mean that I am an expert though.

I ran into this cool link. It mentions that a dirty transmission filter can mimic the symptoms of a failing pump. http://www.freeasestudyguides.com/a2_2.html Lets see what the tranny shop finds tomorrow.

 

[5.0specialist]

The transmission specialist test drove my mustang and it did nothing that was abnormal. He drove it around himself for a while and even took it onto the expressway. He also looked at the TV cable and that looked good according to him. It made that sound again when my dad left the transmission shop as it was about to shift into 3rd gear as always. It seems to be triggered when the car has been sitting in traffic a lot during hot weather. As a matter of fact it only made that sound once and it never did it again. I even drove to school today (20 minute city driving) and it performed flawlessly. No weird sounds. I'm wondering if lack of usage can cause a seal or a valve to kinda leak as it builds fluid pressure. The car was just a show car when the previous owner had it and hardly ever drove it. Anyways, I'm looking into getting a baumann shift kit with a new boost valve (stock ones tend to become leaky) or a broader performance valve body. One way or the other, I'm gonna get this transmission serviced sooner than later before it possibly gets worse.