4l80e issues

[Trucker2k16]

Hey guys I have a 1997 chevy k3500 with a 4l80e in it I've noticed reverse is a second slower to catch than drive and 2-3 feels like it's slipping and hits hard once into 3rd but 1-2 is smooth 3-4 is smooth 4-OD is smooth fluid is full and red and no glitter in the pan I just did a filter fluid change and no metal on magnet and no transmission codes could it be the 2-3 solenoid I've also checked all plugs for corrosion and they are clean and no bad wires. I'm lost other than to buy a new transmission.


Pressure is in spec.

 

[dbrannon79]

what's the history on the trans? anything leading up to it doing this?

 

[Trucker2k16]

what's the history on the trans? anything leading up to it doing this?

214k on it no it started doing it a while back and didn't think anything of it till now

 

[dbrannon79]

if it's been doing this for a while and there's no glitter in the pan, I would think try replacing all the shift solenoids and see what happens. I'm not a tranny expert but if there are any pressure sensors in there, replace them too.

how did you check line pressure? through a scanner reading the sensors or with a manual gauge?

a pressure sensor could be giving a false reading to the PCM where the front pump is actually getting weak

 

[Trucker2k16]

if it's been doing this for a while and there's no glitter in the pan, I would think try replacing all the shift solenoids and see what happens. I'm not a tranny expert but if there are any pressure sensors in there, replace them too.

how did you check line pressure? through a scanner reading the sensors or with a manual gauge?

a pressure sensor could be giving a false reading to the PCM where the front pump is actually getting weak

A gauge hooked to the side of transmission

 

[jrsavoie]

Personally. If I wasn't confident in my capabilities in rebuilding, I would take it to a good transmission shop with experience in the 4L80E.
I had the 1996 Suburban done for under $4,000, all labor included with a 3 year, unlimited mileage guarantee.
Seems a little pricey, but included all the upgrades.
I'm sure doing it yourself would save huge money. At the time it was behind the Tahoe in line to get in the shed.

 

[dbrannon79]

there is a possible way you might be able to determine if the solenoids are acting up. if you have a scanner that you can watch live data while driving. see what the PCM is commanding and the delay time when the trans actually responds. if there is a delay or sluggishness from when the PCM commands a gear change to the trans actually changing. this can be ether the solenoids or possibly something in the valve body creating a blockage.

you could try a bottle of motor pur in the trans, then go driving like a maniac for a bit. that stuff will usually flush out anything in the valve body, sometimes will fix the problem. but I would recommend changing the fluid and filter afterwards. then solenoids while your in there for cheap insurance.

sometimes driving habits can account for buildup in the valve body too. what ever you do, don't try "flushing" at a lube shop, that will break loose stuff that will destroy the trans.

though mine was working fine, I had a tank replaced on my radiator, while I had it out I decided to spray a little brake cleaner into the trans cooler and use my air compressor..... you wouldn't believe the that came out of it!!! After guys had told me the same, never to flush at those trans shops (the ones they connect a machine to the line to flush) I saw why. you can remove and flush lines and coolers separately like this but make sure you get it all out including the chemical you use to clean it.

 

[dbrannon79]

 

[Trucker2k16]

Personally. If I wasn't confident in my capabilities in rebuilding, I would take it to a good transmission shop with experience in the 4L80E.
I had the 1996 Suburban done for under $4,000, all labor included with a 3 year, unlimited mileage guarantee.
Seems a little pricey, but included all the upgrades.
I'm sure doing it yourself would save huge money. At the time it was behind the Tahoe in line to get in the shed.

Not worried about the cost I may try sensors first then replace the whole trans

 

[Trucker2k16]

there is a possible way you might be able to determine if the solenoids are acting up. if you have a scanner that you can watch live data while driving. see what the PCM is commanding and the delay time when the trans actually responds. if there is a delay or sluggishness from when the PCM commands a gear change to the trans actually changing. this can be ether the solenoids or possibly something in the valve body creating a blockage.

you could try a bottle of motor pur in the trans, then go driving like a maniac for a bit. that stuff will usually flush out anything in the valve body, sometimes will fix the problem. but I would recommend changing the fluid and filter afterwards. then solenoids while your in there for cheap insurance.

sometimes driving habits can account for buildup in the valve body too. what ever you do, don't try "flushing" at a lube shop, that will break loose stuff that will destroy the trans.

though mine was working fine, I had a tank replaced on my radiator, while I had it out I decided to spray a little brake cleaner into the trans cooler and use my air compressor..... you wouldn't believe the that came out of it!!! After guys had told me the same, never to flush at those trans shops (the ones they connect a machine to the line to flush) I saw why. you can remove and flush lines and coolers separately like this but make sure you get it all out including the chemical you use to clean it.

I gotta put in year 2000 to do live data due to the tune I am running but haven't yet

 

[Will L.]

Depending hot hot it’s been in past, how hard it was worked- 214k might be beginning of the end.
Yeah try a few little parts- and maybe drop the pan to see the filter isn’t plugging a bit since last change may have washed some gunk free.

But imo the price of things is on the rise and is not going to be slowing down for the next year. If you can afford it- you might be better off redoing the whole trans now rather than nickle & dime it for another 1.5 years then have to rebuild it anyways and have to pay the more inflated price then. It’s all about your personal cash flow. This is probably a bad biased viewpoint because I believe in repairing everything else on a component level- except automatic transmissions. But I am not good at diagnosing transmissions so this may be why.

 

[Trucker2k16]

Depending hot hot it’s been in past, how hard it was worked- 214k might be beginning of the end.
Yeah try a few little parts- and maybe drop the pan to see the filter isn’t plugging a bit since last change may have washed some gunk free.

But imo the price of things is on the rise and is not going to be slowing down for the next year. If you can afford it- you might be better off redoing the whole trans now rather than nickle & dime it for another 1.5 years then have to rebuild it anyways and have to pay the more inflated price then. It’s all about your personal cash flow. This is probably a bad biased viewpoint because I believe in repairing everything else on a component level- except automatic transmissions. But I am not good at diagnosing transmissions so this may be why.

No idea how it was treated this is the truck I posted few years back that I restored and everything was great I never towed with it it was a daily but yea I just did the filter and fluid 2 days ago I can buy a new one for 2700 or put all new sensors and a harness in it either way something has to fix it lol