I am new to this board and just discovered the "pre 1997" area. I had posted this under transmissions but only received a couple of replies. Here goes:
My new 92 F150 with the 351 CID and the E4OD that I recently purchased has a very hard shift from D to R after the engine has warmed up. The shift has about a 3 second pause then bam, it goes into R. Same thing shifting back into D. I have discovered that if I shift into N and increase the idle about 100 RPM, the shift is smooth as silk. This seems to make sense since the idle is a little faster when the engine is cold and shifts are okay then. Checking the manual I find that it states that the idle speed is not adjustable and do not attempt to adjust. Well, reading between the lines, I assume that I would screw up some other area of the transmission or something. My questions to you folks is this: Am I on the right track? Should I attempt to adjust the idle? Since I do not know when the last tune up was preformed, should I get a complete tune up and hope that the engine would run a little faster at idle? The engine runs great and I am satisfied with the truck. It does have 127K miles on it but has been well maintained by the original owner. I am kind of between a rock and a hard place here, any help you can give would be appreciated. Thanks

 

I wish I could help you but I have only had the exact opposite experience. Mine will jump when put into reverse if it is cold and still idiling high, but once it has warmed up and dropped to its normal idle it is smooth. I would think that since it is behaving in a way that seems counter-intuitive (it is smoother at higher rpm's) that you may want to have the transmission checked. Do you know what the previous owner used it for? Might give you some clues if it is wear and tear and where to look.

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1993 F-150 SWB Supercab 4.9l 4 speed auto w/ OD, 3.55 gears, K&N fipk, Custom Exhaust w/ Flowmaster.

But to chip or not to chip? Hmmmmm...