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Air testing the valve body in a 4r70w automatic transmission

1116 Views 2 Replies 3 Participants Last post by  hscheffler2
I am looking to buy an air compressor for air testing a 4r70w automatic transmission in my 98gt. I am just beginning to research what I need and what to do. What air compressor would you recommend and also what attachments would be needed to do an air test? I have the entire 4r70w disassembled. Valve body is completely dissembled, I am currently doing a JMOD while I wait to buy an air compressor. Are there specific tools needed to air test the valve body?

I found a 22 GAL 125 PSI Campbell Hausfeld vertical compressor. On facebook marketplace for $100 and the Output gauge is broken on it. Would this work for an air test and is it worth the price?

Perhaps someone could share a link of detailed guide or video on air testing the 4r70w. Thanks for helping.
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I have no idea how to conduct that test. But for buying air compressors, the most important metrics IMHO are continuous compressor volume (CFM) and tank size. For example, if your tool uses 7 CFM continuous at 90 PSI, a compressor rated at 5 CFM at 90 PSI cannot keep up with tool air consumption. This means the compressioor will be continuously running after it exhausts the tank volume. If you buy an oil-less compressor, the components will heat up pretty quickly which is not good. Keep this in mind when considering compressors and tools.
Buy it! It only takes about 30# of air to test any valve body or clutch pack in an automatic transmission
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