1994Z.I just put in a fresh 4l60e. When first taking off.The car acts like it only shifts up once (1st to drive.) I also have no overdrive. It runs about 2500-2800 rpm going 55-60. If I come to a stop then take off, it acts like its still in drive(engine a bit loaded like you tryed taking off in 3rd gear in a manual transmission equipped car). If I try manual shifting from L. It runs normal then when I go to 2 nothing happens then D it shifts up. I'm told I need to scan the computer to see what codes I have. Is it possible for the computer to be causing this? I would think manual shifting it should shift normally. Does the computer have that much control to cause a problem like this? Or does it sound like this fresh trans has some internal issues?

 

hey, sounds like you've cut a servo ring....from what your saying no 2nd or 4th...right??Sounds like a servo problem ...pull the servo and check the sealing rings..It's on the out side of the tranny pass side big round thing...hope this helps Dave

 

Could be a servo problem like Dave said. It could also be a shift solenoid. Even in manual ranges, the computer still commands the solenoids. If a solenoid is bad, you'll get inaccurate shift scheduling. 3rd gear is "fail safe" in a 4L60E, which means both solenoids are off. Something as simple as a blown fuse can cause this...but...when it goes into fail safe (limp mode), you usually ONLY have 3rd gear.

Frank
CPT

 

thanks guys, can I pull the servo without special tools and with the trans still in the car? Also do I need to drain the fluid first? Should I go this route first? Or go get the car scanned.

 

The servo will come out with the tran. in the car. You will lose a little fluid, but it's not necessary to drain the trans first. The best way to get it out is to pry the retaining ring out with a screwdriver placed in the opening of the case (Small opening at 6:00). The cap will pop out some, revealing an o-ring. You'll see it through the opening in the case. Get something in there and pull tension on that o-ring. I use a pick with a 90* end. Sometimes the cap will come off without having to cut the o-ring...sometimes it's necessary to cut the ring with a pair of dykes and pull it out. The cap should come off easily, once the o-ring is out of the way. Pull the smaller 4th piston off the end of the pin first (it may stay in the cap). Remove the 2nd piston, and then the servo/pin assembly. Check the teflon rings in the servo itself. there should be a large and a small one. Make sure the rubber o-ring on the 2nd apply ring is good.
When you reassemble, make sure the servo return spring is in place. This is the spring between the case and the servo. "glue" it (with vaseline) to the back of the servo for best results. The 2nd apply ring slides on the main servo with the flatter part facing the main servo assembly. You may need a new o-ring for the cap, if you had to cut your original. Make certain the metal retaining ring is fully seated in the case. If it's not, it will come out!

Frank
CPT

 

well that sucked! I cut the hell out of my hand on the cat heat shield. Anyhow I pulled the ring and cover. A smaller hockey puck piece(had back-up ring intact) - then a larger hockey puck piece(had o-ring intact) - then I couldn't get the next puck out - so I removed the ring,washer,and spring from the shaft and pushed in on it so I could get the next puck out. I assume this was the piston/servo It had a smaller and a larger back-up ring (intact) and a spring behind it. Then I put it back together. Had a helluva time getting the ring back around the cover and seated in the case. Any other suggestions?

 

could something sticking in the valve body cause this?

 

pulled the pan to investigate. The electrical connector that hooks to a solenoid on the front drivers side(red and white wires)hidden under the trans filter, was not hooked up. Hooked it up, works great!

 

Sometimes we over look the obvious. That is your 3-2 down solenoid. This thing should've kicked a code.

Frank
CPT