Torque conveerter lockup question.

Midnight87

"87 EC with 305 and metric 200 trans. The torque converter keep locking and unlocking while out on the highway. This is constant on/off situation. Any ideas what can be causing this? The only changes from stock is that the air pump was frozen so I took off the associated smog equipment. Distributor and carb are still computer controlled.

dougs85 · Posted: Sun Mar 16, 2008 9:11 pm Post subject:

I can't believe GM was using that POS transmission in '87. I had that in my '85 and after the second time it crapped out I had a TH350 put in. Don't spend any money on a metric 200. That is a light duty trans and it has no business behind a V8 even a 305. You can have a rebuilt TH350 trans installed for about the same price as overhauling a metric 200.

A TH350 trans works real good with a 2.41 real axle ratio and will replace a metric 200 without any mods.

Doug
_________________
85 El Camino 305, TH350, K&N, dual exhausts
87 El Camino 305, 2004R, K&N, dual exhausts
1964-1/2 Mustang conv, 260 V8, dual exhausts
2002 Jaguar XJ8, 2000 Harley Road King
Lakewood, CO

Midnight87 · Posted: Sun Mar 16, 2008 9:31 pm Post subject:

You are so right. I am very aware of the 200's reputation. This particular trans was rebuilt last year by the previous owner but that means nothing. I have a 700R4 ready to go in already. What I need to know is why is the converter locking/unlocking all the time, if it's a problem with the ECM then it's hitting the trash barrel too. If it's just the trans then I will be rid of it soon.

dougs85 · Posted: Sun Mar 16, 2008 10:35 pm Post subject:

Since the converter locks up part of the time, I doubt the computer is the problem. Even if it is you can wire around it with a kit from Bowtie Overdrives. Link
http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=OA1

Doug
_________________
85 El Camino 305, TH350, K&N, dual exhausts
87 El Camino 305, 2004R, K&N, dual exhausts
1964-1/2 Mustang conv, 260 V8, dual exhausts
2002 Jaguar XJ8, 2000 Harley Road King
Lakewood, CO

87ElCamino · Posted: Mon Mar 17, 2008 4:22 am Post subject:

If it's an 87 it's probably has a 200-4r transmission, which is a good transmission. The ECM controls the torque convertor lockup. First, you need a scanner to see what the ECM is doing. It may be something as simple as the TCC unlock switch on the brake pedal or the 4th gear pressure switch.
_________________
Ernie
87 El Camino
Rolling Eyes

"To be Old and Wise, you must first be Young and Stupid"

dougs85 · Posted: Mon Mar 17, 2008 8:43 am Post subject:

Hey Ernie, does a 200-4R trans have "metric" embossed on the pan like a 200 metric?

Doug
_________________
85 El Camino 305, TH350, K&N, dual exhausts
87 El Camino 305, 2004R, K&N, dual exhausts
1964-1/2 Mustang conv, 260 V8, dual exhausts
2002 Jaguar XJ8, 2000 Harley Road King
Lakewood, CO

Midnight87 · Posted: Mon Mar 17, 2008 9:10 am Post subject:

It is definitely a metric 200, there is no overdrive. Also the gear indicator is only for a 3 speed. I am changing all this so what is in there is a moot point. All I need to know is if the constant lock/unlock problem is trans related or computer related. I will be removing all trans related possibilities but I need to know if the computer could possibly be acting up causing this problem. If it is, then I will have to replace or do away with the computer. I have a scanner, albeit not a real good one, all it showed was a faulty EGR code.

87ElCamino · Posted: Mon Mar 17, 2008 6:37 pm Post subject:

bigdave396 · Posted: Wed Mar 26, 2008 11:57 am Post subject:

Could also be the convertor too. But the computer needs to be checked to see if the ecm is telling the lock up solenoid to turn off and on. Or the solenoid its self.

Midnight87 · Posted: Wed Mar 26, 2008 12:24 pm Post subject:

Thanks bigdave, I had a trans expert tell me almost the same thing except he didn't feel the computer was the problem. It doesn't matter the trans and the computer are both coming out of the car soon.

elcamman006 · Posted: Thu Mar 27, 2008 1:11 am Post subject:

what does it do when the conver stops?

Midnight87 · Posted: Thu Mar 27, 2008 8:12 am Post subject:

Engine speed drops or climbs 300-400 rpm when it locks or unlocks.

bigdave396 · Posted: Thu Mar 27, 2008 12:38 pm Post subject:

your welcome man i used to work for a tranny shop. so i hope it helped you out.

bigdave396 · Posted: Thu Mar 27, 2008 12:41 pm Post subject:

spoonplugger · Posted: Fri Apr 04, 2008 11:03 pm Post subject:

This response is a little late, but better than never. Right? I had the same problem and found the problem was a faulty Throttle position Sensor (TPS). Apparently, the rheostat had a bad spot in the coil. The TPS is located in the electronic carburretor. About $26.00 from Auto Zone, if memory serves me correctly. Before you replace it, be sure you know how to adjst the voltage and make sure you have the adjsuting tool in hand, otherwise, it's a pain in the butt.
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86 caballero, 350 cid, TH350C