I recently had a TH400 transmission rebuilt and i asked the person who did it to put a shift kit in. There is a very long story to this - the first rebuild failed almost right away and i had to return it so he repaired it under warranty. The guy had like 50 cars in his lot to fix and 7 other transmissions to rebuild....
Anyway, i just put the new one in (on a cold snowy day in my driveway) and it shifts fine, but it shifts exactly like my original one did and i wonder if he really put the shift kit in this time. Can you tell by the way it shifts if it has a shift kit? My friend has the same van with the same trans and a shift kit (rebuilt by the same person) and it shifts different - later and firmer than mine.
thanks,
Paul

Check the vacum signal first at the modulator. If your vacum is low, you will not have any line rise ( pressure ) and that will negate your shift kit performance. You need about 13 to 14 inches of vacum at idle and that value must drop instantly at throttle opening. Remember, low vacum= high pressure and firm and later shifts. High vacum= low pressure and soft, sometimes slippery, and early shifts. This can be adjusted at the vacum control ubit at the front of the engine. Call me if you need help.
mike

thanks mike.
i have a brand new vacuum pump but i will check there. Are you supposed to disconnect the line at the vacuum modulater and put a vac guage at the end of it, or are you supposed to T off that line with it still connected to the modulatar and a vacuum gauge on the T?
thanks,
Paul

thanks mike.
i have a brand new vacuum pump but i will check there. Are you supposed to disconnect the line at the vacuum modulater and put a vac guage at the end of it, or are you supposed to T off that line with it still connected to the modulatar and a vacuum gauge on the T?
thanks,
Paul

Paul
I made a goof in my post where I said low vacum and low pressure. High vacum is low pressure and low vacum is high pressure. You need to put the gauge at the regulator on top. That way you can adjust the regulator while watching the gauge.
mike

Grease, just pull the line off the modulator and hook your vac guage into it. You should have around 15 in of vacumn and it should drop to 0 when you press the accelerator to the floor.

An '87 6.5 Diesel will not generate 17" of vacuum unless they've designed a "new and improved" vacuum regulator valve (VRV) since I last purchased one. I rarely see more than 13" at the modulator. Most often, it's around 11" at the mod. I use an adjustable modulator and usually have to back the screw out almost all the way to achieve a low speed, light throttle shift. (with a stage-2 shift kit installed)

The VRV needs to be adjusted all the way up, vacuum hose bibs closest to the bulkhead. This combination will give the highest vacuum reading to the modulator, the rest of the adjustment is done with the screw in the modulator.