Oldsmobile/Buick Repair: transmission troubles??, shift into overdrive, vacuum source

Question
hello, I have a 1987 olds98 4 door 3.8lt v6 front wheel drive , 4 speed trans, my problem is when driving it it shifts into second gear and stays until youhave to speed up to 130-140km then shiftsinto drive ,as you drive along slowly it just shifts down as if you where stepping on the gas to pass someone ,i have replaced the trans filter and oil,part number fram FT1072 TRANS FILTER im not sure which trnas it is other then it has 19 bolts that hold the pan on  i was told it is the "large one ".when you take off from a stop sign not speeding but normal driving ittakes alot of rpm to shift from first to second and even more to come out of second  then eventually does shift into overdrive for a short time then kicks down by it self.there is a number on the vacuum modulator its a "HOLLEY 726" if that means anything to you any suggestions would be helpfully thanks again         jody

Answer
OK, You most likely have the TH440 transmission.

It is possible that the modulator is faulty but FIRST check to make SURE you have a vacuum source to the modulator with the engine running.

If you had had ANY work done on the engine it is highly possible that the vacuum line may be damaged. Mkae SURE there are NO leaks in this vacuum line PHYSICALLY inspect it.

However, IF the trans fluid is discolored and or has a BURNT smell to it, The trans will have to be tested for proper fluid pressures and most likely be removed and dis-assembled for internal inspection.


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