I am looking for some more assistance with my 84 F250 that sat for a year while I was in Iraq.

Symptoms: It is shifting hard from gear to gear. It is also not wanting to hold a higher gear once I ease off on the throttle. There is no grinding or hesitation going into gear, just shifting between gears.

What I have done: I changed the transmission fluid and filter this moorning. The fuild was dark reddish brown and pretty thick. I check the fluid throughougly for chips or shavings and there were none.

What I am thinking: I just finished working on the glow plugs and was working a lot around the fuel pump area. I read in the Chiltons that on gas trucks you can make adjustments which affect the transmission at both the Carb and the tranny. Is the same true with the deisel, and if so can anyone give some advice. I assume that the linkage adjustment at the tranny will be the same as in the Chilton.

I was also wondering if I need a replacement valve body.

Anyone have any ideas.

Thank you in advance, Jaysen

 

There should be a vac. line running to the vac. modulator. Check and make sure this is still hooked up or if it broke or cracked. The vac. mod. should be on the pass. side of the tranny. Also pull the vac. line off the vac. mod. and see if tranny fluid runs out of the line, if it does you have a ruptured modulator and it will need to be replaced. If none of this is the case, you should be able to adjust it to get the desired firmness for shifting.

 

Try this, check the vacuum too.........

How to adjust VRV by James

You don't have the engine running for the test, you need to apply 20" vacuum (Hg) 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" vacuum (Hg) 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 (Hg). 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

Note..... 20" vacuum Hg is equal to MINUS 65 Kpa..........