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Eric Deslauriers
08-20-2003, 05:13
So after putting my rebuilt IP back in, I noticed what appears to be an oversight in the DP R&R guide - how to adjust your vacuum kickdown sensor after putting it back on your IP.

Or I just missed it. smile.gif

Anyone know how?
britannic
08-20-2003, 08:37
Assuming you have the TH400 (the kickdown on most of these is triggered by a full throttle switch at the diesel pedal in conjunction with the vacuum valve) here's what you need:

There's the correct way to do it (see below), or the seat of the pants method, which I used, which is simply to adjust the trans. vacuum valve on the IP by rotating it toward the cab a bit at a time, until your shifts are where you like them.

Here is the proper way, which of course should be used :D to prevent damage etc.:

1. Install transmission vacuum valve on fuel injector pump with 2 screws. DO NOT fully
tighten screws. Transmission vacuum valve must be free to rotate on fuel injector pump.

2. Attach vacuum source to lower vacuum nipple. Attach vacuum gauge to upper vacuum nipple. Bring vacuum down to 20 in. Hg.

3. Insert valve gage block (fabricate from .646" bar stock) between gauge boss and wide-open stop
screw on throttle lever. Rotate and hold throttle lever against valve gauge block.

4. Loosen the 2 transmission vacuum valve screws, if not already loose. Slowly rotate transmission
vacuum valve clockwise (toward front of truck) until vacuum gauge reads 8 in. Hg. Hold transmission vacuum valve in this position, and
tighten 2 screws.

5. Check adjustment by releasing throttle lever then rotating throttle lever against valve gage block. If vacuum gauge does not read 8 in. Hg,
loosen 2 transmission vacuum valve screws and repeat steps 2-5.
Eric Deslauriers
08-20-2003, 21:23
So I take it my Mightvac won't do the trick. :(

Thanks, I'll give 'er a go!

BTW, yeah it's a TH400
Eric Deslauriers
08-21-2003, 02:41
ROTFLMAO. Either the vac sensor isn't that touchy or I'm damn good. Got it on the first try.

Guess I paid better attention to where it was than I thought!