Automatic Transmission - slight surge from 1st to 2nd

[rockola1971]

4L60E Massive Planetary Carnage and No Reverse. All because of a stuck checkball in the separator plate

 

[29tomt]

2000 LT 5.3L V8 2WD Tahoe, automatic with 200,000 +/- miles.

History:​

Automatic transmission was completely rebuilt about 6 years ago.

About a year ago, the transmission started slipping with some hard shifts. The transmission fluid looked normal (for the age). I removed some transmission fluid and added 24 oz. of Lucas Transmission Fix. This made it run a lot better, but not perfect. Added a 2nd 24 oz. bottle of Lucas Transmission Fix. This fixed ALL of the slipping and hard shifts! No issues with this since.

However, I still have a slight surge (about 400 rpms) when my automatic transmission shifts from 1st to 2nd when it's cold. It'***** or miss when warmed up to full temperature.

As I've been told, there is a good chance it's just the "transmission going". I'm not really in the place to spend thousand of dollars rebuilding/replacing this again. I was wondering if anyone had similar experiences with this. I'm open to other thoughts.

I also have a suspicion that it could be the Shift Solenoids and I'm considering replacing myself. I'm not sure if these were replaced when I had it rebuilt. It's just a lot to get into if this isn't it. Still, at 200K, it couldn't hurt (other than time and money).

My 2003 same everything has done that for at least 3 years. The Tahoe has 212K miles. The transmission shop did not see anything out of the norm when replacing fluid and filter but went ahead and replaced the 1-2 shift solenoid with a Corvette part number with small improvement. I did notice if I give it a little more pedal when taking off from stop that it does not do it. I am thinking it is more of a computer feed issue than worn tranny. Maybe cable, TPS, whatever in that area. The 1-2 solenoid is external so not much of an effort to replace I believe to be the case. Good luck.

 

[ROGELIO A GUZMAN]

I recently did a fluid flush thru the radiator cooling line. I thought it changed most of the fluid, but I was wrong. I recently had a check engine light about a shift solenoid. So I took the pan down and replaced both solenoids and filter. Let me tell you that the fluid was still pretty bad. I did have a small slip from 2 to 3rd and this fixed it. Solenoid s where pretty cheap from the dealer ( 20 dollars each). I would recommend you fellas replaced them when ever you drop the trans pan. Now my trans is shifting like butter and for some strange reason my mpg went up 2-3 mpg. I did use full synthetic fluid. Just my 2 cents.

 

[SnowDrifter]

Saw additives. Didn't read thread.


1. Remove fix in a bottle from trans

2. Change fluid, filter, pickup tube gasket. Get yourself to a known good starting point. Make sure you're not sucking air or that the filter isn't plugged because someone forgot a rag in the pan or something.

3. Check solenoids - might need a shop's help or tech 2 scanner. You'll be looking at actuation time.

4. Check slack in second gear band. There are different length pins you'll put on the server to get to appropriate tolerances

5. Check condition of servo

6. These transmissions are electronic. They will compensate for wear. If you're getting shift flare but not slipping under load, the transmission isn't 'going.' It's failing to compensate because something in the hydraulic path is being slow or obstructive. Think about it for a second - no slip means static pressure and friction material is fine. Flare means actuation is slow, which means it's either flow rate or actuation speed. This gives you a spot to look.

7. Check codes. TPS / MAF issues will do funny stuff with these transmissions as it uses both of those metrics when determining shift points, time, and pressures.

 

[findog78]

Did you find out what the issue was and able to repair it? My '04 just developed the exact same flare about a month ago. Fluid looks and smells fine?

 

[Jerome Nelson]

View attachment 358659

This is the 2-4 servo cover. See if you can push it in and measure or just try judge how far it moves. If it moves more than an 1/8 of an inch, the band is worn or pin is too short. Need a longer pin or new band which a band is rebuild territory

I was finally able to get under there and feel for it. I wasn't able to push it in at all. It just wouldn't budge by hand. Perhaps I could have use some leverage, but I am assuming just trying to move it by hand was the appropriate test. What does that tell us?

 

[Mudsport96]

I was finally able to get under there and feel for it. I wasn't able to push it in at all. It just wouldn't budge by hand. Perhaps I could have use some leverage, but I am assuming just trying to move it by hand was the appropriate test. What does that tell us?

Sorry should have been more specific. You will need something to pry against it with. Let me see if i can come up with a video for you.

 

[Mudsport96]

Well i was unable to find a video. But you need to use a pry bar on it. Use either the torsion bar or frame as your pivot point.

 

[Jerome Nelson]

Well i was unable to find a video. But you need to use a pry bar on it. Use either the torsion bar or frame as your pivot point.

Thanks, Mudsport96. Sorry for the slow response, I assumed I would get an email notification, once someone replied. I'll try and get back under there in the next few weeks. Thanks again!