4L80e No engine braking

[Supercharged111]

I would check the seal on the 1-2 servo

If there's a problem with the servo, wouldn't there also be a problem when trying to accelerate in 2nd?

 

[tayto]

If there's a problem with the servo, wouldn't there also be a problem when trying to accelerate in 2nd?

the servo just engages the 2-1 band, you will still have 2nd or 1st with this band off

 

[alpinecrick]

if your dropping it from 4th to third, this is supposed to happen. if u are going from 4th to second, the coast clutches are letting it roll so you dont tear **** up. why all the dropping of gears, ? are u climbing hills, trying to be hot rod man? just put it in drive and leave it alone.

There are places outside of Texas that ain't flat........

I downshift my 4L60E's all the time. And they go into the gear I select.

 

[Supercharged111]

the servo just engages the 2-1 band, you will still have 2nd or 1st with this band off

Ahh, derr, servos aren't for clutches. Maybe mine's leaking too, but I definitely lost the overruns whereas OP did not. But there are separate low and intermediate bands, does this servo actuate both of them?

 

[tayto]

no, the 2-1 band aka front band is controlled by 2-1 servo (as i mentioned) and the low/rev band aka rear band is controlled by low/rev servo. The first 4L80e HD2 shift kit i did like 8 or 9 years ago lost engine braking in 2nd, i ended up nicking a seal on the 2-1 servo.... maybe you are right and the overruns are not coming on if no engine braking at all in any manual range.

 

[Supercharged111]

no, the 2-1 band aka front band is controlled by 2-1 servo (as i mentioned) and the low/rev band aka rear band is controlled by low/rev servo. The first 4L80e HD2 shift kit i did like 8 or 9 years ago lost engine braking in 2nd, i ended up nicking a seal on the 2-1 servo.... maybe you are right and the overruns are not coming on if no engine braking at all in any manual range.

My band should also be coming on to provide that engine braking in 2nd though, both the overruns and the band are engaged per the chart I posted above. Unless the band smoked itself trying to do it all once the overruns bit the dust.

 

[tayto]

i always thought overruns did engine braking in 3rd, but the front & rear bands did 2nd and 1st respectively but i haven't done a lot on 4L80e to be fair, mainly shift kits over the years.

 

[WannaBe1Ton]

So i went and tested it again. 2nd DEFINITELY does not engine brake at all. it coasts better than 3rd. However the low band does engage because it engine brakes in first. So one thing i’m possible looking at is the 1-2 servo/ the seal for it. It could have possibly been knicked when it was built. I know it’s got a shift kit put in.

 

[Supercharged111]

Do you get effective engine braking in 3rd?

 

[WannaBe1Ton]

Do you get effective engine braking in 3rd?

I mean it’s adequate for third gear. It’s not gonna slow down with a 8 thousand pound trailer but it will hold the truck at a steady speed down hills and it will slow me down on less severe hills and flat land so long as i’m not super loaded up. But yes it’s definitely noticeable as compared to being in overdrive.