I have a 1978 F-100 with a C-6 tranny, rebuilt less than 100 miles ago by someone who normally does damn good work on GM trannies. I noticed a wicked slip on the 2-3 shift yesterday while driving home, checked fluid, its fine, so I crawled under the truck to check the modulator valve to make sure it was tight, hose was ok, etc., and when I pulled the vacuum line, transmission fluid ran out...is this normal? If it turns out to be just a bad modulator valve, that sure would beat having to pull the tranny for a 3rd time. If it isnt, I think I might have to find another transmission mechanic....where is your shop at again???
question for transurgeon
Apr 16, 2004
2 Replies
nope
modulator diaphragm has ruptured
make sure you don't lose the PIN between the modulator and the valve when you replace it
order the modulator BY APPLICATION, from the dealer..........there's quite a few different ones
Thanks! Hopefully I can get it took care of sometime this weekend, and I'll let you know how it turns out.
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