4L60E..suddenly wants to Lockup the TC in 2nd, 3rd, and OD?

[454/4X4]

OTher day I was driving home, and I noticed my 94 Z71 felt sluggish, I looked down and it was doing like 35mph, turning like 800 rpms, obviously...not right.

When I went to stop, the tach dropped to like 350, then rose to about 800, then dropped to about 350, then up to about 1500...at which time I was in 1st gear, going about 10mph, and was able to stop.

Its clear, that, in any gear other than 1st, the TCC is locking up. Tapping the brakes and slowing down, does not force a release. the trans is locked 1:1 over 15mph, in any gear other than 1st.

I checked the connections i could find under the truck, all were clean and tight, fluid is/was up to the full line, filter/fluid is only about 6K miles old. Trans was totally rebuilt with a new TC about 15K miles ago.

The shifts seem to come at the right speeds, but its hard ot get a read on it because its like1st....2nd.LOCK....3rd..LOCK....and the engine has a hard time keeping up.

But it shifts at about 15mph t0 2nd, and 25mph to 3rd, I never let it go to 4th for fear of stalling out.


I dropped the pan, and ive ordered a new TCC solenoid...im hoping that fixes it, any other ideas to look for?

 

[rhino]

It's most likely the solenoid, but when you take the solenoid off, you can take a small scribe or pocket screwdriver and make sure the valve behind the solenoid is not hung.

 

[454/4X4]

The solenoid on this one has a long plastic tube with an o-ring on the end, and it goes straight up into the trans, where is this valve located?

 

[rhino]

When you unbolt the solenoid, it's behind the long tube. The valve is in the pump, but it comes out from behind the solenoid. When the TCC solenoid turns on, it sends pressure stroking the valve which sends pressure to the lockup clutch in the converter. The valve is held in with a snap ring, but you can use a small pick to see if it's in the "stroked" position. If you need me too I can text you a picture, I'm building one today.

 

[454/4X4]

So basically, on top of the tube there is a pin type thing, that hangs down, I should be able to use a probe or pick to push it up some....and if not, it is stuck in the open position, allowing fluid in at all times. forcing the TCC to lock in sall gears but 1st?

 

[rhino]

It's not so much a pin that hangs down. It's a snap ring that's holding a valve in. If the valve is already mashed up, it's hung. If you can push the valve up, and it comes back down as you let off, (it has a spring behind it) it is free. The hole is small, so it takes a small screwdriver or scribe. The reason it don't kill the engine in 1st gear, is 2nd gear oil feeds the TCC circuit. So as soon as second gear oil is applied, your solenoid is stuck in the open position letting fluid stroke the valve, or the valve is stuck in the stroked position.

 

[454/4X4]

just picked up the new solenoid, qts of Dex6, and a filter...will know shortly.

 

[454/4X4]

WELL, IT GOES 1ST, 2ND ,3RD...4TH....BUT will not lockup at all.

I found I was able to suck and blow on the old solenoid, but the new one i could not, so, I think it was definitely bad. But now, no lockup.