OD issues with 90 sc

neverfastenough

Registered User
I will try to explain the problem the best that I can. If I am running a little over 45 in Overdrive and approach a steep grade the car will naturally start to lug. But it I let it lug enough to downshift on its own it will come out of overdrive and rev up before it decides to go back into drive. If I dont lift it will continue to rev instead of shifting. Ive Found ways to avoid it and it rarely happens but Im courius what it could be. If I get on it in OD it downshifts perfect, or if I let off completely when it lugs it shifts fine. Its somewhat done it since new but the neutral it hits between 3rd and 4th seems longer anymore. I hope you have an idea of my problem any help is greatly appreciated
 
It sounds like the OD band is starting to go. This is not uncommon in an AOD after this number of years of service. You might also want to check to see that the TV (throttle valve) cable is set properly. That and a fluid change could buy you some time, but once the band starts to go, it will continue to get worse until you have no OD at all....:(
 
I will second that and add that if you continue to drive the car it will destoy other things in the trans. Sorry to say but it sounds like a rebuild is in order.
I have had 2 of these tranies go just like you described. Tell you what thou, If your good with cars and have the right tools, rebuild it yourself. I had never done one myself untill my sons trans went. Went to a trans parts place, bought the AOD rebuild book, read it about 5X, bought all the parts including the TQ converter, master rebuild kit and OD band for under $300 she worked like a charm. Your going to find thats its all on one shaft well sort of but the valve body you must pay special attention to namely how it goes back to gether. Its a good time for a shift kit as well.
 
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