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Discussion Starter #1
1994 Cougar, 101000 miles

Last fall my 4R70W was giving me the shudders right around the 3rd/OD area. I found this site and did the following: I replaced the fluid (including the fluid in the torque converter) with Mercon V, installed new filter (and drain plug:)), and changed the 1-2 accumulator piston with the new rubber type. When I replaced the 1-2 piston, I found the purple spring under it broken. I replaced it with a spring of similar size and strength from a local transmission shop. The shudder is now gone!

But now every time I decelerate from a high enough speed, the car will lurch as I get close to 30mph. Say I'll be going 55, and the light turns red- so I start braking... 55, 45, 35, *lurch*, 25... and stop. It always does this when I'm braking but it doesn't feel like the brakes; it sure feels like a downshift. Any ideas?
 

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I say it IS the downshift, maybe a sub assembly in that old VB sticking or worn.
 

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Discussion Starter #4
Sorry for the late reply, I have very limited internet access.

I'm now pretty certain it's the 2-3 piston needing replaced. The 1-2 was pretty easy... I understand this one's behind the valve body. How do I get behind there? Are there any balls or springs that will fall out if I start removing bolts?

If I happen to find a broken spring in there like I did with the 1-2, should I go with the same colour one?
 

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Drop the valve body, replace the piston with a new one and forget about replacing the spring.

Joe
 

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It's supposed to Downshift around 30 of course & I'm not so sure the lack of 2-3 Accumulator Spring does'nt make Downshoft a tad more "pronounced" - Check your U Joints for sure - Could be Bushing within Tranny galling & getting ready to seize up & die.
 
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