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4l80E Problems! - (Scott - Trans shop Reccomendations?)

dhcomp

dhcomp

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Ok, bought my 91 3/4 ton burb with 196k on the clock. Now has 213k. Trans always shifted awesome at WOT, felt like it had a good shift kit in it, very firm quick shifts.

Changed the trans fluid/filter around 205k, no issues.

This truck has the 350, so i spend a lot of time at WOT. The truck always shifted really firm, felt great, until last week. Started shifting a little slower, and slipping a little before it softly shifted. Uh oh. Shifted a little slow, but i decided to keep monitoring it. This went on for a couple hundred miles.

Went to tow the boat home, flat ground, highway, and it was obviously slipping. Shifting slow, not able to hold OD, feeling gutless when i got on it hard.
Then it stopped going into OD.

Checked fluid level, may have been a little low, added some. Wasn't low enough to cause damage, not burnt, and no leaks. Hard to tell the level with fresh ish fluid. Has correct amount of fluid now.

Let it cool down, took it for a drive, shifted slow still, but into OD fine.

Any ideas what is causing? I bought this truck for this trans specifically....if it needs a rebuild, i am going to be pissed. To the best of my knowledge, this truck has a recent crate motor in it, and i always figured the trans was recent too, but no idea.

Any vaccuum hookups or wiring things that could cause this? Or does it need to be evaluated by a trans shop? I am cringing right now just thinking about what a rebuild will cost.....definitely close to the value of the truck :(

Any insight? Scott, do you have any good trans shop reccomendations?

Thanks guys!
 
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I would say right around 2000 for a complete overhaul

but if you like the truck thats cheap compared to buying something newer
 
yellowK20 said:
I would say right around 2000 for a complete overhaul
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Yep, thats what i am thinking. Hoping that isn't what i need to do. Paid 2150 for the truck, and just spent over a year convincing myself to fix the ac for $600 :doah:
 
well from the pics I've seen that you've posted the truck is nice enough to spend the coin on!!! 2150 was a pretty good deal if you ask me
 
Well I'm in the same boat !!! just found out that the 4L80E in my new 91 crewcab is nuked
and I only paid 1000.00 so......
 
George_Pimpdaddy said:
wonder if towing in OD caused it? also do you have a bigger aftermarket cooler on it??
Click to expand...

Stock cooler, fresh fluid. Towed in OD, but boat was only 3-5000lbs, nothing major. I also was very adamant about not letting the trans EVER hunt between OD and D, or letting the torque converter lock/unlock in OD.

I have a tach on the truck, so i am very aware of normal operating RPM's, changes in behavior, etc.

So any chance a lockup wire or something isn't connected? Still hoping for a simple solution......:(
 
Just get under it and look at the wires if you are woried about something not being connected. Hate to tell you, but it does not sound like a wire issue. The computer probably locked out the OD due to high heat from the slipping. It sounds like your clutches are shot.
 
I'm just really surprised that it was such a sudden change. One day is banging off shifts as firm as ever, and the next day its all sloppy. The 4l60e in the blazer went out a lot more progressively, instead of all at once.
 
Get a used tranny out of another vehicle. Replace it and drive down the road. You can get one and have it installed probably for around 1000. Buy a kit to rebuild the other one and do it yourself on a day off. Get a good tranny rebuild book and go at it. If you make a peg board for removal order putting it back together will make life really really easy for you.

Used tranny's are a gamble but check it out and of course check for leaks or signs it used to leak. I've so far had no problems with used parts in my area on well over 25 vehicles and 19yrs in business. Someone wants cheap that's what it gets. The 4l80e is a very stout tranny and usually doesn't have trouble with pulling or anything. Hope this helps.

PS- Or go on ebay and have a rebuilt one shipped to you then put it in yourself. Around 1000 for those.

Josh
 
what ever you do make sure you flush out your cooler and cooler lines before you put your new tranny in
 
uh. Ok. Not looking to replace or rebuild trans myself. I need it reliable on too short of a timeframe to make this happen, and truthfully, am considering selling all my old POS trucks and getting something newer.

I'm sure we all have those days.....

If i am going to fix this, i will find a reputable shop, and get it built.
 
Can you check it for codes? The 4l80e puts out codes that you can not read with a normal obd deal. I had to take mine to a trans shop and they read the codes. I ended up with a 1/2 solenoid going out and a manifold preasure switch. $250 later I was working fine again. I did take it to one guy that wouldn't even check the codes, just said it needed a complete overhaul that was $1500.

So don't let someone BS you on this.
 
cuervo said:
Can you check it for codes? The 4l80e puts out codes that you can not read with a normal obd deal. I had to take mine to a trans shop and they read the codes. I ended up with a 1/2 solenoid going out and a manifold preasure switch. $250 later I was working fine again. I did take it to one guy that wouldn't even check the codes, just said it needed a complete overhaul that was $1500.

So don't let someone BS you on this.
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Right on man, this is the information i wanted to hear. As soon as i chat with Scott, and take his recommendation on a shop, i'll go get it scanned :waytogo:

Out of curiosity, where do you read the codes from?
 
honestly with 200,000 miles it most likely not a solenoid or other minor problem.
and since it started after you changed fluid that leads me to believe your clutches were already really thin and that new fluid with its good detergent in it kinda "washed" what was left of your clutch material away and now she's slipping..... you did say that it slips in all gears now??

anyways I know it sucks to spend the coin but a complete overhaul would be better than messing with bandaid fixes even if it was a solenoid pack or something along those lines you'd still be looking at a rebuild in the near future

you may want to check into a GM parts reman tranny from the dealer they have bitchin warranties and are not overly priced ...... let me know what ya do I'm in the same boat know but I wont get to touch mine until july when I get back from this work trip
 
yellowK20 said:
honestly with 200,000 miles it most likely not a solenoid or other minor problem.
and since it started after you changed fluid that leads me to believe your clutches were already really thin and that new fluid with its good detergent in it kinda "washed" what was left of your clutch material away and now she's slipping..... you did say that it slips in all gears now??

anyways I know it sucks to spend the coin but a complete overhaul would be better than messing with bandaid fixes even if it was a solenoid pack or something along those lines you'd still be looking at a rebuild in the near future

you may want to check into a GM parts reman tranny from the dealer they have bitchin warranties and are not overly priced ...... let me know what ya do I'm in the same boat know but I wont get to touch mine until july when I get back from this work trip
Click to expand...


With the condition of the motor, and the condition of the trans and fluid that i removed, i don't think either have more than 50k on them. The trans fluid was cleanish when i changed it, or i would not have wanted to risk messing it up.

I just have no records as to when it was changed.

I'll look into dealer tranny's, but i'd want to get a shift kit and some other upgrades if i do end up rebuilding it, so we'd see what makes the most sense. I'll keep you all updated.
 
well good luck!!! its a sweet rig and well worth spending the money to fix. My truck is a turd and I'm still gonna fix it lol. sure beats a Truck payment!! Plus how can you measure money against how cool these trucks are!!!
 
yellowK20 said:
honestly with 200,000 miles it most likely not a solenoid or other minor problem.
and since it started after you changed fluid that leads me to believe your clutches were already really thin and that new fluid with its good detergent in it kinda "washed" what was left of your clutch material away and now she's slipping..... you did say that it slips in all gears now??

anyways I know it sucks to spend the coin but a complete overhaul would be better than messing with bandaid fixes even if it was a solenoid pack or something along those lines you'd still be looking at a rebuild in the near future

you may want to check into a GM parts reman tranny from the dealer they have bitchin warranties and are not overly priced ...... let me know what ya do I'm in the same boat know but I wont get to touch mine until july when I get back from this work trip
Click to expand...

You read the codes from the odb connector under the dash, but the normal reader didn't pull tranny codes. The owner at my local trans shop had a box about the size of a loaf of bread that he connected to the odb port and my cig lighter.

He got three codes out. I post in this forum asking for help and there wasn't much of it when it came to 4l80es.

My tranny ran fine for a long time and hard shifts from 1st to 2nd. It had 373s in it so I'm not sure how long it was without OD. It could have been since I bought it. Anyway, it start slipping and taking off in 2nd and then would shift down to 1st build preasure then shift to 2nd. I change the fluid and it made some difference but slowly came back.

I took it to the trans shop and he pulled the codes and then replace the 1/2 solenoid and preasure switch. Everything sweet after that.
 
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