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By working on it
I rarely drive my 135000 mile 2004 Chevy 2500 since I retired, usually just to tow my home-built squareback trailer (2250 lbs) on camping trips. Before retirement, it was a hauler for my drag race car (for 5 years), towed my camper (for 9 years, now), and also my daily-driver (for 5 years, then part-time after I bought an HHR panel as my daily). The bed is full of camping gear and emergency-use supplies (about 800-1000 lbs), year-round, so it sits while other cars and trucks get more usage.
After sitting for three months this time, I changed the oil, topped up some other fluids, and took a 500 mile trip with my trailer attached. Sometimes, if I started off too hard from a stoplight, the 4l80e felt like it was slipping, but not so much if I feathered it at the start. At first I wondered if it might've been a U-joint getting loose, but a quick test underneath proved it to be OK. Furthermore, when I pulled off into soft mud, it really slipped before it grabbed (two-wheel-drive). Though my 6.0L engine/4.10 rear combo has no trouble pulling the 2250 lb trailer, I started using tow/haul mode on the second half of the trip, whenever I was either braking in traffic in urban areas, or when taking off from a dead stop. No slippage when tow/haul is engaged.
I had the solenoids upgraded about 50000 miles ago, when stop & go daily driving in rush hour traffic was causing erratic behavior, and I used Lucas Transmission Fix about 25000 miles back, when I felt a slight slamming into second gear (upon part throttle). In each case, the problems went away. I didn't check my transmission fluid before the trip, I confess, but I did check the tranny pan, rear seals, differential for signs of leaks, and found none. On the trip home, I stopped just around the corner and bought a new grease gun & cartridges (for the driveline, which may need some, though I did the front end 10k miles back), and a 24 oz bottle of Lucas Transmission Fix (if the fluid level is low, I'll just top up...if the level is OK, then I'll drain/siphon 24 oz and replace with Lucas). It worked before, so why not try it again?
So I’ve searched all over and can’t seem to get a straight answer to what I’m experiencing. So I have a Black Bear Tuned 03 GMC Sierra 1500HD with the 4L80E 4 Speed Automatic transmission with the ability to Manually shift 1-2-3.
My understanding is that when I Manually shift it down into 1st gear it’s suppose to lock it into 1st gear so it revs up way higher and engine brakes to slow down but does not shift until I manually shift up to 2 or 3 or put it back in Drive. Well when I lock it into 1st gear, the revs are much higher but it still automatically shifts to 2nd gear once I get close to 25-30mph even though I have 1st gear selected.
Is Manual shift lock not working for me?
Has anyone else experienced this?
I just don’t get the point of manual shifting if it’s still gonna shift up automatically anyway 🤷♂️
Thanks for any input!
Hello! To whomever may have any advice. I recently bought a 2005 gmc single cab with a 6.0 4l80e that wouldn’t start unless you put a little fuel down the intake and jump the starter(which I didn’t do bc I’d rather fix the problem logically). Anyways so a problem that I found is that he had actually broken the ignition interlock cable on the steering column and you were actually able to turn the key by hand but turning it to the start position wouldn’t do anything other than a like if you would say meh out loud that’s literally what the engine or I believe the electrical would sound like when you turned the key into that position. So I replaced the wire from a donor steering column which was a PAIN!!! anyways I have the original column in with the new wire but it’s still not trying to start at all. I also noticed that the throttle body doesn’t open when you press the Gas and you can’t push it open. It also makes a small humming noise like it wants to try to open and slightly vibrates. Also so I jumped the 87 pin on the starter relay to the positive and the engine turns over but won’t fire and start. I’m assuming that it’s a fuel problem(yes I put fuel in the tank today 7gals). So my next theory is going to maybe test the starter? I’m not really educated on this stuff but I do have the tools for the most part. Any advice would be appreciated. ALSO it has a newer ignition Solenoid and it has the lock and car light on the dash so I’m not sure if the new keys have to be programmed and that has anything to do with it? Maybe? But I’m not sure and thank you again! I’ll post a link to a YouTube video tomorrow to show exactly what’s going on and what I’m working with for a visual!
By Jonathan Mantilla
Hello everybody, I’m really stumped on this issue I’ve been having on my 4l80e, it’s a 1989 c1500 with a 5.3 ls and 4l80e, the transmission has its own stand alone harness, it was working fine for about a year until one day the transmission did not want to shift, the trans ecu is reading tps , rpm, speed perfectly fine , the transmission is not shifting , only reverse and drive works, cannot manually shift, if I power off the trans ecu the transmission will just got into limp mode and stay in 2nd gear , I’m confused what the issue could be? Any help will be appreciated
I'm trying to buy a 2004 Silverado 1500hd with the 6.0 and 4l80e. When test driving the transmission would shift through all the gears fine but if you let off the gas as soon as the rpms hit 2000 they would drop to 1500 to 1000 and there would be a loud grind/whine until you tapped the gas again. I'm assuming it's the transmission, maybe the torque converter. Any help would be great so I can figure out if the transmission would have to be rebuilt or if it's something simpler to fix
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