P0776 SunCoast Valve Body

slowlb7

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Feb 10, 2014
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des Moines iowa
Got my new SunCoast valve body today and took the truck for a drive got the transmission up to temp and it threw P0776 (pressure control solenoid b performance or stuck off). It won't clear and now I'm stuck driving 13mph home. Did they send me a valve body with a bad solenoid, or would something else cause this? Also had a p0872 after driving 20mins home
 
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slowlb7

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Feb 10, 2014
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des Moines iowa
Tranny was rebuilt last month with sun coast parts and converter, transgo kit, mike l spring, new bearings. all filters were replaced, new oil pump. Drove 20miles got the p0872 pulled the valve body took it apart to try to free up the e valve put it back together drove maybe 15 miles valve stuck. took apart valve body again cleaned it, messed with the e valve put back together valve was still sticking. Ordered a valve body from sun coast as no one would help me fix my old valve body put new filters and fluid in today, drove truck, got the p0776 and later the p0872 codes. tranny has maybe 80miles on it still haven't beat on it. There nothing on either magnet, nothing in the pan. it had a working tranny before the rebuild. No it happens on the 1-2 shift and stuck the truck in 1st gear
 

durallymax

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Apr 26, 2008
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Under The Hood
Who built it? Any chance something is not together right in trans? P0776 is not a good code to get. Happens when trucks shear the p2 planet/c2 hub connection often due to a shift tie up. When this happens your truck will generally shift through to 4th but when it goes to 4th the truck will stop accelerating.

I've had more trucks come in with that code due to c1s welded together from burnouts. Truck will do some weird things.

Enough times people overlook the mechanical parts as being the issue.

Sent from my SCH-R970 using Tapatalk
 

slowlb7

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Feb 10, 2014
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des Moines iowa
I built it. I'm sure there was no tie up shifts + wouldn't it take a good bit of throttle on the tie up to broke it lol the tranny has about 80 easy miles no burn outs or even half throttle pulls much less full throttle on big tunes
 

Evan@InglewoodTrans

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It only takes a split second to hurt hard parts. The tie up is why I asked you about the 3/4 shift. Start by checking the easy stuff like output speed sensor which can cause your code then go from there.
 

slowlb7

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des Moines iowa
How am i going to test the out put speed sensor when i cant really drive the truck? Put it on jack stands and see if it reads? I hope mike has some other ideas
 

Mike L.

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Was it throwing P0776 before you so called built it? If not, you probably did something wrong inside the trans. p0776 happens when an on coming clutch applies before an off going clutch releases. this could be a speed sensor, or something miss assembled in the trans. The P0872 leads me to believe the problem is internal.
 

slowlb7

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Feb 10, 2014
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des Moines iowa
No it didnt before the build and didn't on the old valve body. why didn't it do this with the old valve body i tried to fix a p0872 code but got a p0772 code from just changing valve body's



Was it throwing P0776 before you so called built it? If not, you probably did something wrong inside the trans. p0776 happens when an on coming clutch applies before an off going clutch releases. this could be a speed sensor, or something miss assembled in the trans. The P0872 leads me to believe the problem is internal.
 

slowlb7

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Feb 10, 2014
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des Moines iowa
Output speed sensor seems fine it works and don't drop out. When the TCM commands 2nd. Gear it wont shift and it will code p0776 and then command 4th gear clear the code and shift into drive and hold the brake it will code p0872 and command 4th when the TCM commands 4th the truck stills moves so wouldn't that mean i have 4th gear and the p2 isn't broke?
 
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2005LLY

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Sep 18, 2011
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When my p2 broke it sounded like a can of marbles in the trans, it also stuck in 4th gear.