Trans Shift Points

[ezgn]

I think I have two like new condition modulators. I'd be willing to part with them cheap. I now have a 4L80 so no need for it.

Really need to take a vacuum reading at the modulator. It's going to take some time to set it up with a tee fitting and some extra hose but it's a shit in the dark without knowing what is actually at the valve before it goes into the modulator.

Do you need to tee off the hose going to the modulator, or can you just put a hose onto the metal line going to the modulator and hook your gauge up there?

 

[Skinny]

Do you need to tee off the hose going to the modulator, or can you just put a hose onto the metal line going to the modulator and hook your gauge up there?

You could go anywhere after the valve at the pump but the best place would be right at the modulator. If you have a delivery issue and take the reading up near the engine you will be chasing your tail. There is a long metal tube going down the transmission, could have a pinhole or crack.

I would test it at the best place that will give you the most results which is right at the trans.

 

[Keith_J]

Top tube to transmission. The reason for the vacuum is this transmission was designed for use behind gasoline engines where manifold pressure is a good indicator of engine load. The modulator adjusts hydraulic pressure to the clutches and adjusting shift points.

Adjustment of the VRV is detailed in the -34 TM. There is a gauge block tool, dimensions are available so a chunk of aluminum, a vise, a file and a good calipers will get you there.

 

[dmetalmiki]

check your vacuum modulator, they are often the source of shifting problems.

 

[ssdvc]

Skinny, sent you a PM.

 

[pl1338]

I think I have two like new condition modulators. I'd be willing to part with them cheap. I now have a 4L80 so no need for it.

Really need to take a vacuum reading at the modulator. It's going to take some time to set it up with a tee fitting and some extra hose but it's a shit in the dark without knowing what is actually at the valve before it goes into the modulator.

Did that 4L80 bolt right up or did you need to make some things work?

 

[trooper632]

Did you ever get the issue fixed