Hard Shifting still after repairs

[niferous]

Ok I replaced all my vacuum lines and the vacuum regulator on the side of my injector pump and I'm still having problems with hard shifting. I used an AC Delco regulator and ran the line from the top to the line going to the trans and the bottom port to the vacuum pump.

Now here is the strange thing. When I did this the truck shifted great. However I wasn't able to drive it for about two weeks due to the dash and instrument panel being pulled out. When I finally got it all back together and drove the truck to try out my stereo it was shifting smooth but doing so very late for second gear. Now it does shift around 30 mph after I rotated the regulator up towards the air cleaner but still it's a little stiff and I can't really feel the shift.

I should mention that the modulator on the side of the transmission is also a new BWD part.

Any ideas of what I should check next and how is appreciated.

 

[m38inmaine]

Check the pump, make sure you are pulling 24in or so at idle.

 

[jsrovers]

I was wondering about the "hard shift" as well. I find that when the vehicle is cold it shifts smooth as can be. Like really smooth. When it warms up to operating temp the shifts are very choppy and hard. Anyone have any input on this or is this how they are?
Thanks...

 

[101coolcars]

My truck was acting up the same way, i ran "sea foam" trans conditioner in it and it perked it right up. maybe gummed up internal parts? hope that helps.

 

[niferous]

Check the pump, make sure you are pulling 24in or so at idle.

How do I go about doing that? I assume there is a tool out there to check it?

 

[Goose2448]

Is it the Turbo 400 or the 700R4? I have a Turbo 350 and an R4 in other trucks and have no problems with the turbo. The 700R4 is a different story. Slow shifting and hard shifts sometimes. Is it just me or are these things bad? You could try a filter change. Worked in my truck.

 

[niferous]

Well it's a CUCV so turbo 400.

 

[niferous]

Ok I drove it to work this morning which is about an 8 mile trip. Before I left I went ahead and pulled the hose off the vacuum pump just to see if it was working at all and it was. I then took off and once again the truck is shifting at 35 mph. Sometimes it's smooth sometimes it's not. The shift into third happens around 50 - 55 mph and is so smooth if you aren't paying attention you won't feel it.

Now I was told I can rotate my vacuum regulator to make the transmission shift sooner which would fix my problem. I drew this picture of my vacuum regulator for reference. Right now it is all the way up next to the air cleaner where it naturally sits without me having to push it into that position? Would rotating it down towards the intake manifold make the truck shift sooner or later?

Also as I stated before I'm using an AC Delco vacuum regulator and I was told the ports are backwards then stock. However I have a sneaking suspicion this could be wrong. Take a look at the picture and let me know if you think I have it hooked up right. If the hoses are backwards would the truck shift at all?

Thanks!

 

[scottc]

I own one and been around several 1008's it has been my observation that they just shift hard sometimes, sometimes not so much, I think it is the nature of the beast.

 

[niferous]

But not at 35 mph. I'm checking the vacuum pump tomorrow with a gauge to see if maybe that's the problem.

 

[m38inmaine]

All the way up should make it shift sooner.

 

[niferous]

Well it just sits that way naturally so I didn't have to rotate it up to that position. I will see if I can adjust it any when I get home.

I went and bought a vacuum gauge from O'reilly's and the pump tested at 24 in at the hose that connects to the vacuum regulator. I went ahead and ordered a new filter and gasket while at O'reilly and they should be here tomorrow morning.

Tonight when I get home I was thinking about checking the metal line that runs down to the vacum modulator on the side of the transmission. Should I be getting any vacuum on the end of that line while trick is at idle?

 

[niferous]

Ok I got home and messed around a little with the vacuum regulator and that didn't yield any results other than making the truck shift later when I rotated it down.

I checked the vacuum coming out of the hose that connects to the metal line that goes to the transmission. It was at about 11 in. I then got underneath the truck and tested the vacuum at the hose that connects to the vacuum modulator. I was getting barely 4 in of vacuum. Is this normal or has anyone ever checked?

 

[tm america]

you need at least 15 at the trans more vac = softer -earlier shifts .vac should drop when engine is reved up so put a gauge on it start it up have someone give it throttle it should drop .if you stomp it to the floor it should drop almost to 0. adjust it however you have to to get the vac about 15 at idle at the trans

 

[rizzo]

I bought a new vac regulator and it has a shift adjustment screw inside the vac port. I have mine set to shift at 25 and IIRC 40-45

 

[niferous]

I bought a new vac regulator and it has a shift adjustment screw inside the vac port. I have mine set to shift at 25 and IIRC 40-45

What brand was it?

 

[lavarok]

Ok I got home and messed around a little with the vacuum regulator and that didn't yield any results other than making the truck shift later when I rotated it down.

I checked the vacuum coming out of the hose that connects to the metal line that goes to the transmission. It was at about 11 in. I then got underneath the truck and tested the vacuum at the hose that connects to the vacuum modulator. I was getting barely 4 in of vacuum. Is this normal or has anyone ever checked?

Blow out this line with compressed air.
I had one clog on me before.....

disconnect from the tranny and blow air into it from up top.

then retest for vacuum. You should not loose any vacuum from the top to the bottom.

 

[niferous]

Well as the saying goes look for the most simple answer and that will fix the problem. When I checked the vacuum at the modulator I should have checked the whole hose. It had a huge hole in the hose right where the metal line comes down and it couples too. I replaced the hose and now I can barely feel it shift. Hopefully others with hard shifting trucks will read this and check ALL HOSES all over not just where they can be seen as they are on the vehicle. By the way this was a brand new hose that split.

 

[doghead]

Great!

 

[4x4 Forever]

Glad you r back up and running Nif, and thanks for the helpful information!