m1009 strange trans issue.

m1009k5

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fox lake/il
This issue has been going on for a while but is getting progressively worse. i've searched around but can't find anything since i'm not sure exactly how to describe it..

So when i have it in d, 1st gear feels fine from a stop, it then goes into 2nd, and feels like it slips. but the rpms dont flare up or anything like that. it just doesnt motivate. once i hit 3rd gear, everything is fine.
I have noticed that i can manually shift it into 2 while its acting up in 2nd gear, and all of the sudden it starts to feel like it should, like the power is actually making it to the wheels. If i shift it down to 1 at a stop, and shift it all the way up, everything seems fine.

if anyone has any ideas i'd be really glad to hear them.
 

bearboley

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Circleville Ohio
My guess would be the second gear drum band is slipping. I would say when you let it shift on its own the rpm's are down and the pump pressure is down but when you manually shift it I bet you run the rpm's up enough the added pump pressure tightens the clutch band just that little bit more. Just a guess.
 

wkbrdngsnw

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Aurora,Co
Does it engine brake in manual 2nd? The accumulator for 2nd is ceramic from factory and can fracture. When this happens 2nd gets really sloppy in drive and has a hard time engine breaking.
 

m1009k5

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fox lake/il
It doesn't seem to engine brake in 2nd when in drive, at least not very much. But with the lever in 2 it does seem to brake a bit more. It's hard to tell though, since the trans also seems to upshift so fast.

While i was reading through as many trans issue threads as i could, i saw lots of people describing late, hard shifts. I have the opposite going on. Sometimes it seems to skip first altogether, and its in 3rd pretty quick. I don't know if this is related to the 2nd gear issue i'm having now, i probably should have mentioned that right off the bat.

i'm starting to think it might be time to save for a rebuild.
 
With 3L80s, if there is any problem, it is usually in need of a rebuild. At least that's been my experience. I'd agree with WK... er, post #4.
No engine braking in D2, or 2nd gear is usually the front servo or front band. Someone could have changed out the fluid and filter thinking it might help, which basically does nothing but lead the next guy into thinking the trans is not burnt when it really is. You can reach the front servo by dropping the valve body, so you might want to check that out first, and if it is indeed cracked, or the pin, seal or bore ar damaged, you will know where to go from there. Hopefully, the bore of the case is not damaged, otherwise, finding someone willing to part with another HD case for one of these units is sometimes like pulling hen's teeth.
 
One other thing to check with early or soft shifts is the governor. If it is sticking, it can create high governor line pressure, which will trick the valve body. Matter of fact, that would be the first thing I would look at with your symptoms since it only requires removal of 4 bolts and a new gasket. What you want to do is make sure it does not wiggle in it's bore, which I doubt it will, since that would cause low g-pressure, and make shifts late and hard. Next, pull it out and hold it by the bore-end, with that end pointing up so the weights naturally fall into the open position, then squeeze the weights in and out and see if the piston inside moves up and down freely. If there is anything sticking or binding, you've just found your problem. Also, it is good to wash it off and blow it out to make sure everything moves when it is dry.
Hope this helps!
 

chevyCUCV

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Massachusetts
Where's the hijack smiley?
Hmm, my truck does not engine brake in second gear anymore, it used to. But when i put it in 2nd the other day, it acted like it was in nuetral when i was off the pedal

Still drives the exact same, i dont think i would have noticed if i didnt hit 2nd by accident( my shifter indicator broke one day and i like the trickery everytime someone moves my truck)
My googling told me that the 2nd gear engine braking is its own band, so i should be fine driving it around still. Not worried about killing it, i am not a fan of automatics
 

m1009k5

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fox lake/il
but if you drive your truck with the shifter in D, and you let it shift 1st to 2nd, and physically move the shifter into 2 while you are already accelerating in 2nd gear, does it feel like it starts to move better? when you move the lever i mean as opposed to letting 2nd ride out till it shifts.
 
Something I had forgotten to mention, the front band only comes on when the shifter is in D2. It is actually not needed any other time, including when it shifts into 2nd gear when the shifter is in D3. I vaguely remember my trans-builder mentor telling me many moons ago how you could take the front band from a 3L80 and throw it away during a rebuild, and the unit would still work fine as long as you didn't need D2. The components that are engaged when this trans is in 2nd gear with the shifter in D3 are the forward and intermediate clutch packs and the intermediate roller clutch, and that is it, the forward band is not used to acheive 2nd gear when the shifter is in D3. So with this in mind, I believe the problem with the OP's trans is in the governor assembly, but then it is really difficult to properly diagnose a trans without being able to drive it.
 
308
11
16
Location
Bear Creek PA
One of the transmission parts firms makes a upgrade and update kit. It has heavy duty frictions and a modified plate for the valve body that enhacnes the 6.2 performance. I thought I bought it from Jeggs and the kit was from TCI. If you do a rebuild it would be a good idea to use this kit. I rebuilt my 6.2 dieselpowered 2500 Suburban with the kit and 80K miles later its still going strong and shifts great.
 
308
11
16
Location
Bear Creek PA
I looked around for the box, I do not have it any more. Here is the number for TCI, I bought the hi tourque diesel converter kit and the super kit for the transmission ( has steels and frictions and every wear part and seal in the transmission. I had installed the towing valve plate but unless you tow a lot, you really do not need it.

TCI® Automotive
151 Industrial Drive
Ashland, Mississippi 38603
Toll Free: 888-776-9824
 
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