Hey guys. Ive been trying to figure out if my transmission problem(4T40E) is worn clutch or solenoid related. It runs great when its cold. The shifts are fast and tight. But after driving for about 15 miles, the shifts from 1-2 become way too soft, and at WOT, 1-2 shift bangs really hard 3 times, and slips. Can you have clutch chatter in an automatic? Sometimes it takes 2 seconds to complete a 1-2 shift if its really hot. Also at WOT at a stop, it slips just a little bit, shudders, and then grabs tight and takes off. Anyway, I put in a bottle of Lucas Stop Slip and it made nearly no difference. So if it was worn clutches, that thick junk would of made at least a little difference, right? So im thinking that the pressure control solenoid is bad. There are no codes. What do you guys think? Thanks in advance. You guys are always awesome!!
Transmission Acts Funny when Warmed Up
- Thread starter ChevyGuy3100
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if it works flawlessly when cold, wouldn't that indicate the thicker viscosity is actually helping? I would try a fluid that is thicker when hot, compared to the one your currently using.
I had a similar issue in my Infiniti. When hot, the 1-2 shift became sloppy. Sometimes it would bang, other times too soft. A D&F with MaxLife helped a little. I then added 2 bottles of Lubegard red and that has almost entirely fixed it for the past 5 months. Sometimes after returning to city driving after a long highway trip, the shift is a little hard but otherwise everything's good. The LG also tightened up the rest of the shifts as well.
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I have the same problem on my 2005 Buick La-Sabre.
Around town, its ok, but on a road trip it starts the same stuff yours does. I ask the transmission place in our town and he said they have to most likely go inside of the transmission and check out the solenoids, estimated repair with labor and parts, at least 400 bucks....well that was his opinion and they have been in business here for over 30 years. As far as using lubegard, I have put this in my transmission, but it cant fix a solenoid going bad, otherwise lubegard is one of the best additives you can use, just google it.
Around town, its ok, but on a road trip it starts the same stuff yours does. I ask the transmission place in our town and he said they have to most likely go inside of the transmission and check out the solenoids, estimated repair with labor and parts, at least 400 bucks....well that was his opinion and they have been in business here for over 30 years. As far as using lubegard, I have put this in my transmission, but it cant fix a solenoid going bad, otherwise lubegard is one of the best additives you can use, just google it.
Well I added the Lucas stuff and the fluid is really thick now. But its still just when the transmission gets hot. As far as changing the fluid, I changed it every 20-30,000 miles (all my driving is in the mountains or in city traffic). I tried Maxlife, around 160,000 miles and it did not like that at all(lubegard was added) At around 185,000 I did 2 drain and fills with Pennzoil Dexron iii and that did great. At 217,000 miles I did 2 drain and fills with the blue bottle valvoline. Around 220,000 miles is when it started the slipping and banging stuff. Just a few thousand miles ago I did 2 drain and fills with supertech Dexron iii spec fluid and a bottle of lubegard and 3 days ago I decided to try lucas. Have 235,000 miles currently lol. So yeah its probably worn out. Btw I had 2 coolers in series at one point just to experiment with it. The converter never locked up because it ran too cool.
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