Air Check Reverse using Test Port

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Nov 1, 2023 | 07:28 PM

4r100 Help

Thread Starter

3rd Gear

Joined: Nov 2023

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Air Check Reverse using Test Port

Is anyone familiar with process of air checking a 4r100 using the test port and if so could you describe the process? I have a 4r100 that I recently rebuilt. It has all forward gears, but a weak reverse. I would like to check the entire reverse circuit rather than just the L/R clutch pack. The process I'm asking about is mentioned in a Transmissiondigest.com article titled "The 4r100 mysterious no 3-4 shift. However when I tried it with the transmission still in the truck, fluid just poured out what I assume is the fluid return port.

Another question would be how much air pressure should be used when air checking? There doesn't seem to be a standard, usually just suggest low pressure?

Thanks I really appreciate this site and it's knowable contributors.

https://www.transmissiondigest.com/t...-no-3-4-shift/

Last edited by 4r100 Help; Nov 2, 2023 at 11:40 AM.

Nov 2, 2023 | 10:57 AM

1Butcher

Cargo Master

Joined: Mar 2007

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I'm no expert, but when I did my E4OD, the port is in the back of the housing and the intermediate plate needs to be removed to access it.

From my understanding, there is only 1 port. Fluid fills and release from that port. Of course, there are many more people that know what they are talking about and can explain it better than me.