Replaced the aod4 in my 1991 250 diesel. Is it ok to drill and tap the intake for a vacuum source for the transmission? Presently I cannot find a source of vacuum for it. The hose "tree" on the firewall is positive air instead of vacuum. larry

 

You won't get any vacuum to speak of out of an intake of a diesel, that's why the accessories are run off a vacuum pump. See if you can T into that. It's the contraption right below the alternator.

 

If you have an E40D there is no vacuum requirement, all inputs are electronic.....from the PCM.

If you have the 3 speed C6 then vacuum inputs are required....... and the VRV requires setting possibly.......

 

Thanks for the comments, I don't know a whole lot about diesels, do know enough to get rid of the e40!! truck has only 175,000, trans had a ford quality rebuilt sticker on it when I took it out, haha. Put a c6 in, does good but haven't got it to shift into high because of vacuum not hooked yet. Used to pull a lot of heavy loads around the farm and not least interested in economy as getting it done. Thanks again, larry

 

Did you replace the FIPL with A VRV, your vacuum comes from the vacuum tree. You will have to setup the VRV......and get the required kick down linkage for the fuel lever on the IP to C6.........

From a posting by James........

How to adjust VRV by James

You don't have the engine running for the test, you need to apply 20" vacuum to upper VRV port and attach vacuum gauge to lower VRV port. The lower port is the one that goes to tranny, the upper to vacuum pump.
You have to maintain 20" througout this test. If it drops off you need to pump it back up.
Remove throttle return spring, cycle throttle lever 5 times from idle to WOT. Make sure 20" vacuum is maintained on upper port side.
Move throttle so it is 0.515" (33/64") from wide open (they make a tool for this). Vacuum gauge should read from 6-8" of vacuum. If incorrect adjust VRV to 7".
Again apply 20" vacuum, cycle throttle from idle to WOT 5 times. Return to idle. Gauge should read at least 13".

It says if you can't get the 7" or the 13" to replace the VRV. If VRV checks out maybe the diaphragm (modulator), line from VRV goes to the vacuum diaphragm I believe. Can't find any adjustment for the diaphragm but I think there is a little.

Basically all you need for the test is a vacuum pump (handheld type), vacuum gauge and a ruler to measure 1/2" or a 33/64" drill bit in lieu of the .515" tool. And a screwdriver for any adjustment needed.
Good Luck
James

 

thanks, sounds pretty easy, larry

 

http://www.thedieselfiles.com/index....directory=Ford

more than you needed to know about the diesel c6 setup.

your welcome.

drew