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I have a GM 440-T4 automatic transmission. Yesterday I started noticing a problem with the shift timing. The vehicle runs up to around 26mph before shifting from 1 to 2 and runs up around 48mph before shifting from 2 to 3. This problem seems to come and go. I kicked the passing gear in, and the problem seemed to clear up, it shifted normally the next time I stopped and started again. Any idea what is causing this shift timing problem? Is something getting ready to go bad? Why is the problem intermittent? Thanks in advance for any info.
 

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I do not have any direct experience with the 440 transmission, however the problem you're describing sounds like the vacuum modulator is not working correctly or at all. Check the vacuum connection going to the unit to verify the source first. If this is good, I would contact a reputable transmission shop to double check the condition before replacing any parts (even though the modulator itself is relatively inexpensive).

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Umm, i had a 'similar' problem in my '84. I replaced the TV cable. It turned out that it was damaged and it was causing it to delay the pull on the cable.

I would try something cheap like that first. The new cable ran me like $10 and solved the problem.
 

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On older vehicles without TV cables, a damaged rubber vacuum line to the modulator is a very common problem, which costs next to nothing to fix. The vacuum modulator, in the rare case that it needs replacement, is less than $20. And, as you pointed out, Dtaney, later model cars have other contributing factors which can result in similar symptoms.

If the free stuff is done first, and it comes time to buy a new vacuum modulator (or TV cable, for the sake of example) it's a good sanity check to ask a friendly shop a few questions to confirm that there is no other major damage to the transmission that could possibly cause similar symptoms.

Far too often people buy parts to fix their cars without methodically isolating the problem first. This is why these discussions are so valuable!

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Oh my dear God, you guys just took a huge weight off my shoulders. I went googling for this exact same problem thinking my transmission was about to go and now I find that it's just the vacuum hoses which I already know need a working over. :hurray:
 

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A 440-T4 sounds like a modern transmission which shouldn't have any vacuum hoses. What the devil is this tranmsission in anyway?
 

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a 440-t4 or called 4t60 is a front wheel drive from 84-93. in 93 and up went to a 4t60-e. the 440-t4 has a cable to the throttle body that will hang up or end of cable end pieces break sticking the cable. the modulator for this transmission controls how hard it shifts.
 
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