I have 120k mi on my '87 GN and am planning on changing the fluid and filter since I need to change my TCC solenoid switch due to an increase in RPM by 1 bar on the tach and back down while in OD the odd time. It's like I'm lightly touching my brake pedal with the gas pedal still on (TCC test). Is there anything else I need to change? I notice on the Monte site where they show this procedure to change the TCC SS that they also show the 4th gear pressure switch. Is there a test I can do to check to see if it needs to be changed or should I just change it?
Anyhing else to change besides the TCC
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DonnieShort
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- May 27, 2001
If you change the TCC solenoid, get the one for a 700r4 ( AC Delco ) it's better. BTW, don't believe the LED factory tach or boost, they are not accurate.
install a test light betwen the pressure switch and battery positive.if the switch is ok itll light the bulb.then unscrew the switch hold the threads on battery ground and the test light to positive and blow air into it to see if the light shuts.if the light doesnt shut its dead.
Go ahead, and replace both the 3rd and 4th gear switches. You won't see anything on the Monte site about it because they have a different valve body than we have. It should be the BRF coded trani, and should be painted pink when you get into it or at least stamped BRF on the side.
I bought all three components (TCC solenoid and both switches) from my local GM dealer for my year Turbo Buick...no shims needed. I'm pretty sure you need the one for the Buick anyway as it has provisions for connecting both switches. I don't think the 700 has the 3rd gear switch, but I may be wrong.
I installed the solenoid and lockup started back, then ended up changing out both switches one at a time. Each time shifting smoothness was improved. Just change them while you are in there and then you will know they are good...might as well if you are going through the trouble. The switches are the same, and will look different if the original ones are still in there. I think they were revised or improved on.
Oh yes, you don't need gaskets or orings for the switch. The thread are tapered.
Just my opinion, HTH
I bought all three components (TCC solenoid and both switches) from my local GM dealer for my year Turbo Buick...no shims needed. I'm pretty sure you need the one for the Buick anyway as it has provisions for connecting both switches. I don't think the 700 has the 3rd gear switch, but I may be wrong.
I installed the solenoid and lockup started back, then ended up changing out both switches one at a time. Each time shifting smoothness was improved. Just change them while you are in there and then you will know they are good...might as well if you are going through the trouble. The switches are the same, and will look different if the original ones are still in there. I think they were revised or improved on.
Oh yes, you don't need gaskets or orings for the switch. The thread are tapered.
Just my opinion, HTH
To the best of my knowledge, the 3rd and 4th switch are the same. I used the same part for both switches. Haven't had any problems at all using them in mine.
I don't have any pictures, or a digital camera for that matter. I'm sure someone does.
Something else...just my opinion...but use the GM pan gasket. They are far better than the aftermarkets. No leaks whatsoever on mine with it. And I have removed and replace the same gasket 3 times. Once for the solenoid, and each time with each switch.
HTH
I don't have any pictures, or a digital camera for that matter. I'm sure someone does.
Something else...just my opinion...but use the GM pan gasket. They are far better than the aftermarkets. No leaks whatsoever on mine with it. And I have removed and replace the same gasket 3 times. Once for the solenoid, and each time with each switch.
HTH
No, no, I mean there is only 1 switch and it's 4th or called 3rd/4th. The parts guy did not see 2 switches. There's 2 switches but 1 switch is on the inside on the valve body and the other one is on the outside on the drivers side. So I'm confused and can't recall when I changed the filter a couple of years ago. I don't want to take the pan off today and find out I need 1 more switch.
Anyone have a diagram? I'm calling GM Parts again.
Anyone have a diagram? I'm calling GM Parts again.
Are you telling me your valve body has only 1 switch? Are you sure? To my knowledge, the 87's had the BRF trani that has two idencial switches, one for 3rd and one for 4th. When I got mine from my local dealer, I think it was just called a pressure switch. Oh yes, found the part number - GM 8683502. My local dealer didn't have a listing for two different switches either. I just used the same on in both positions.
It's been over a year since I was into it, but I think one of them points out the side of the valve body and the other points down out of the valve body. The wiring harness for the solenoid should have 4 wires: 2 for the solenoid itself, and 2 more for the switches. The 2 for the switches are different lengths and only fit to the correct switch. You shouldn't be able to get them crossed up.
It's been over a year since I was into it, but I think one of them points out the side of the valve body and the other points down out of the valve body. The wiring harness for the solenoid should have 4 wires: 2 for the solenoid itself, and 2 more for the switches. The 2 for the switches are different lengths and only fit to the correct switch. You shouldn't be able to get them crossed up.
DonnieShort
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- Joined
- May 27, 2001
You should have 2 switches. One is in the back of the valve body and it is the 3rd gear switch and the second one is on the bottom side of the valve body ( on the passenger side ) and that on is the 4th gear switch. Both switches use the same part number, so if you want to replace them both then buy two switches. Since you've already bought one of them, buy another one ( same part number )
Theres 2 switches on 84-87 BRF or BQ coded transmissions if they have the original vb's in them. If you plan on locking the converter at WOT, use the 700-R4 solenoid. You will need spacers. The pressure switches are the same for third and fourth. Their a pipe thead (tapered) and i wouldnt use sealant on them. It could wind up in the sensing port and screw up the switch. If your vb has only one switch it could be drilled and tapped for the other one (3rd). Chances are, if you have four pins on your case connector its got both switches.
