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Discussion Starter #1
I picked up a '90 SC for $300 because the complaint was the trans slipped. The car was used for towing previously and something was said about clutches being welded....turned out trans lines leaked and was low on fluid.
Drives fine in D, OD doesn't work. It only has 1st 2nd and third....a long 3rd. Around 80mph or so dash says to up shift. Is it possible they welded 3rd&4th to tow?
i bought a donor car for the tranny. It
37849
had a cam, tuned ecu, "built" trans and was told a 3500 stall converter. My questions are can i use the new converter on my stock motor? Should i use the stock converter? Only mods on my SC are cold air intake and deleted mufflers.
Would i need the tuned ecu installed for the new tranny?
I've never modded a car with ecu tuning, trans work or cammed motor.
Please help in NOT making a bad decision in sawpping out ecu and converter.
 

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No, there is no way they “welded 3rd and 4th together for towing”. What is far more likely is that the follow fluid caused th OD band to slip and burn out.
As for that converter, I wouldn’t run it on a stock motor. The idea behind a higher stall converter is under full load it quickly jumps to that rpm to get you into your torque curve. With that high of a converter on a stock SC motor, you would be jumping right past your peak torque, so it will actually make the car slower. Plus an AOD converter with that high a stall speed is probably a non-locking converter, which will cause the engine to rev higher while driving down the highway, creating lots of extra heat and likely burning out the new trans.
 

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Discussion Starter #3
Thanks buddy, i won't use the converter. I'll use the one i have or buy an 1800-2000 one or sell it.
Any thoughts on the ecu with the tune?
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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No, the PCM on the AOD cars doesn't control shifting. That's all controlled by the TV cable.
 

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Don't use a converter from a failed trans. That's a good way to get another failed trans... Plus it's likely worn by the crap in the fluid from the band and clutch material.
 

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Get a Mercury Marauder converter. They stall around 2,800. It's an excellent step up from stock.
 

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Get a Mercury Marauder converter. They stall around 2,800. It's an excellent step up from stock.
A 4r70 converter doesn’t work in an AOD, which a 90SC would have. Also the SC has more low end torque than the 4.6, and so you don’t really want a high stall converter behind a stock SC motor. Honestly the best bet for him if sticking with the AOD would be a converter for an NA V6. Those stall around 2200-2400rpm, which puts you right at the SC’s torque curve.
 

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Thanks Mike. Yeah, I don't know sh!t about AOD's or SC's. My bad.
 
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