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Author Topic: No 3rd gear?  (Read 2447 times)

Offline dburbach85

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No 3rd gear?
« on: February 14, 2017, 09:01:28 am »
Hi guys, checking back in after a very long (about 10 months at this point) 1987 R10 project. The truck was originally a 4.3 V6, but that engine died and I just finished swapping in a nice new 350. Everything seems to be working just fine, except my transmission (Turbo 400) won't shift into 3rd. Or rather, it will when I'm coasting, but as soon as I get back on the gas it downshifts to 2nd and stays there. 1st, 2nd and reverse all work perfectly. Any help?
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Offline bd

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Re: No 3rd gear?
« Reply #1 on: February 14, 2017, 12:06:01 pm »
Check the transmission fluid level and inspect for ATF leaking from the modulator valve vacuum nipple.  Then make sure the vacuum line is securely connected at both ends to the intake manifold and modulator valve.
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline dburbach85

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Re: No 3rd gear?
« Reply #2 on: February 15, 2017, 08:12:09 am »
The transmission fluid level is good, but I'll check out the modulater valve. Thanks!
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Offline Irish_Alley

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Re: No 3rd gear?
« Reply #3 on: February 23, 2017, 12:38:03 pm »
dont forget to check the hose also
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If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes
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