2015 6.2L 8L90 no 3-4 shift after Sonnax kit

[WVRigrat05]

So back story to this issue, I pulled the valve body as a PM job and to also change out the solenoid harness for a temp sensor issue.

I installed both Sonnax Zip kits, a new GM internal harness (Matched the old one to a T) truck initially went straight to neutral when I shifted to 4th, so pulled it apart, thought I addressed the issue....

Now when it shifts to 4th it defuels and tries to shift and just surges with fueling as it's trying to shift but will not go into neutral like the famous 3-4 neutral shift describes. It's been at the dealership 3 weeks they've maybe spent two hours on it, getting upset.

what am I missing? Do I just need to risk an eBay reman or bite the bullet on a 2,700 dollar valve body from next gen diesel?

Thanks for any help guys, trucks been down a month, any ideas would be great, I'm to the point of a valve body or hauling the truck to big dipper for a build if he'll touch it not running correctly

 

[2004LB7]

Moved thread to transmissions

 

[kidturbo]

Sounds to me like the valve body. If you have EFIlive, HPT, or a SnapOn tool, you can engage each clutch manually to verify what's happening. Would verify all the solenoids are activating manually, up on the rack. Maybe find a used valvebody to snap in for a test drive.

 

[WVRigrat05]

Dealership finally got a hold of me after messing with it today, said solenoid 8 is stuck open, said they could replace the solenoid for 2,700 bucks but may not fix it, so anyone have a good known source where to buy a used or reman valve body so I can get this thing going?

 

[Leadfoot]

I'm no mechanic or transmission expert:

That said, $2,700 and may not fix it? Might as well go with the Next Gen valve body...

 

[WVRigrat05]

I ordered a reman valve body, just for the simple fact if it doesn't fix it I'm not out 2,700 on an old transmission. I've got plans for this truck next year, just trying to keep it reliable until then

 

[NC-smokinlmm]

Going to boost it?

 

[WVRigrat05]

I'm at least going back in the motor for a larger cam and get the trans built, still on the fence on a charger or not. I did the 59 LPM?? GM injectors, head work, ARP studs, LS7 lifter, Texas Speed AFM delete, cam, GM timing set and cam phaser, GM oil pump, oil cooler lines and radiator this past spring

 

[PureHybrid]

Which LS7 lifters? My buddy did his Tahoe 50k miles ago and his LS7 lifters from GM are bleeding off / ticking already. Replacement Delphi LS7 from BTR don't look promising either, he took the new ones apart before install and it was sad to say the least

 

[WVRigrat05]

I did the Delphi LS7 lifters. I've heard horror stories on them like this AFTER I got the truck done, I'm gonna go with a set of performance lifters when it's apart next time, along with larger valve springs and some sort of high end trunnions, just did a GM set last time

 

[TheBac]

BTR-V2 or CHE for trunions. No opinion on lifters other than stay away from Morel (failures) and use OEM trays whenever possible.
The C5 Corvette guys area always talking abut these things.....

 

[WVRigrat05]

Tom, I used GM everything as always other than the Texas Speed AFM delete kit and the Texas Speed cam and even the AFM kit has the option of their stuff or GM and of coarse the ARP head studs and stainless ARP manifold bolts.

 

[WVRigrat05]

I was ready to get back in a Duramax shortly but I'm almost 1,500 in on this thing again with tow bills included and I just bought a 2013 90k mile Audi for a spare DD/work car and I'll be damned if it doesn't have a piston slapping (don't hear it unless you revv on it like a HS kid of coarse) so I'm another 6k+ out on it and now getting ready to have a motor put in it

 

[NC-smokinlmm]

That blows

 

[WVRigrat05]

I got a good enough deal on it to deal with it, I just didn't anticipate being over 15k in on vehicle repairs and appliance upgrades in the last two months lol, that's how it goes though

 

[NC-smokinlmm]

My wife’s car blew up on me last month 1.8 miles from the dealership where I was trading it in for her new ride. I feel your pain.

 

[WVRigrat05]

Damn dude that sucks. So my valve body finally shipped Friday, says it'll be here Tuesday, conveniently... I have to go back to work Tuesday night so I'm gonna drive back back in Wednesday morning and take it to the dealership and hopefully they get the damn thing running next week.

 

[NC-smokinlmm]

Hope that fixes it for you, nice to see you on here again brother. Been a minute…

 

[WVRigrat05]

Glad to see you guys are still on here and doing well, time has flown by. I called Mike L's cell phone a few weeks ago and found out he passed away and Evan is running that place now, hated to hear that

 

[NC-smokinlmm]

Yea, Mikes passing still echos thru the community. He was a great guy.