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I have just acquired a 1989 pick-up 5.0L F250 with an automatic trans. On a hill or freeway ramp, If I put my foot in it, there is no passing gear. How can I tell if I have a three speed or aod transmission, and what the shift points are? I need to know if there is a problem with my tvlinkage, or throttle linkage, or if this is the way it is supposed to be. I really could use some input.Thank you.
Look at your shift selector. The 3-speed (C6 in this application I would think) will have D-2-1 and the AOD will be OD-3-2-1. The "OD" will probably be a D with a circle around it.
I don't know the C6 very well, but 35 sounds like it could be a little low for a 3-speed. Check to make sure all your linkages are operating the way they should and are adjusted properly, and if the C6 is vac-operated (I think it is), that all the vac lines are good to go. From 45-50MPH, you should be able to stomp it and get it to go down into 2nd.
the C6 trans shift points are vacuum controlled by the modulator on the back of the case if you pull the vacuum line off most of them will have a screw inside you can adjust, turning clockwise will shift later and counterclockwise earlier, if you do not have a screw inside the vacuum hole, you could get one from a trans shop in your area. the kickdown is operated by the cable or rod from the carb or throttle linkage to the side of the trans where the shift arm is there is a smaller arm that when passing gear is needed it is pushed/pulled by the cable or rod, it might be broken or misadjusted.