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3-4 shift issues, power loss

1189 Views 6 Replies 3 Participants Last post by  Crak88lx
Still working on the Turbo Swap, 88 T,bird into a 90 Mustang. Using an A4LD in the Mustang. I drive it, it shifts fine 1-2 and 2-3, but at about 45mph it acts like it wants to shift again, but will suddenly lose power, not shift and slow down. I can take my foot off the gas, and then speed up slowly and it will shift and I have power again. Also, when the power goes away, the engine light comes on, when the engine light goes off the power is back. At the loss of power the vaccum will go from around 0 to 20 all at once. about 1 out of 10 tries it will shift all the way through and work fine. This is a 2 wire A4LD.

Codes 81, 82 83, 85 and 88.

I am just not sure what is the instigator of this problem. It seems like it is the transmission, but I am wondering if I have some electrical something that is happening that would cause the same problem even if I had a manual tranny in it.

Is there a difference in a modulator valve for a 2 wire vs a 3 wire A4LD?

Any ideas on where to attack this would be great!
1 - 3 of 7 Posts
I'm not a transmission genius by any means but check the vacuum lines, I had a car that miss shifted like this found a leak fixed the hose and bam she shifts. Also check fluid (don't mean to sound insulting).

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No problem. Maybe also try some electric component cleaner on the electrical hookups

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I'd think if that were the issue it wouldn't work at all, but as stated earlier I'm not a transmission guy.

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