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2015 transmission abruptly quit pulling

5K views 18 replies 10 participants last post by  TransEngineer 
#1 ·
Story is this. Driving down the road yesterday and transmission just stopped pulling. No prior issues at all. Acts like it just went to nuetral. No unusual noises. Stopped. Put it in park and turned off truck. Put back in Drive and headed off. Got 2nd and 3rd gear to shift then it would jump back to first gear for a bit then quit pulling again. Did this a few times to limp it to the dealer as I was pretty close to one. Truck is all stock except wheels/tires with 30k miles. Now towing except small loads. Any ideas? Thanks in advance
 
#2 ·
One likely cause is a blown accumulator cover (on the side of the main valve body). Typically, if that covers blows open, you lose the OD clutch, so you only get 1-2-3 and then it neutrals out when it tries to shift to 4th. Most shops will want to replace the entire valve body, but there is a repair kit available (for about $20) that consists of a new accumulator cover plate, one new accum piston with seals, and new screws. If multiple pistons are damaged, you can also buy individual pistons.

So hopefully that will be the cause of your failure. Easy fix if (hopefully) the OD clutch itself isn't damaged.
 
#7 ·
Sorry to high jack, but the updated cover is that something I should think about doing to the valve body in my 2010? It's just the factory one. But I am runing mcc with trans turning.
 
#4 ·
2015 with 30k that's still under 3/36,000 warranty correct?


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#8 ·
It should be covered. I have the 5/100,000 warranty. Just curious as what may be wrong. I haven't pulled anything over maybe 2000lbs with it and I baby the truck. I do out of town runs picking up parts for my business and am happy it at least happened a few miles from the local dealer
 
#9 ·
i'd almost guarantee the accumulator plate thing flew off

either need a valve body(if any of the bores are scored and/or the threads for the bolts are pulled out), or a new piston and plate and bolt kit

either one should be covered by the 5/100 warranty
 
#12 ·
Typically, one screw (next to the OD accumulator bore) loosens up, backs off, and falls out. With that screw missing, the OD accum piston puts so much load on the one of the remaining screws (the other one that's right next to that piston) that it pops the head off the screw. Then the piston bends the end of the cover plate out from the valve body, until finally the piston moves far enough that its inner seal ring comes out of the bore, giving you a huge leak in the OD clutch passage (so OD no longer works, and you get the neutralling out on a 3-4 shift). So usually you will find one loose screw, plus the head of one other screw, in the pan.

The broken screw can typically be turned out of the valve body by hand (it won't be tight), and then the cover and OD accum piston replaced.
 
#13 ·
Interested in this post. My truck just did the same exact thing. 3-4 shift felt like it went into neutral. It went into 1st gear limp mode right away. You could drive it if you locked out at 3rd gear. Truck is sitting at the dealer right now.

Hopefully they are smart enough to figure this out..
 
#17 ·
If yours is a failed accumulator cover, all it takes is dropping the pan and valve body (about 1 hour of labor) and an accumulator cover kit (05174633AB) which I'm guessing might run $25-30. Plus fluid. Now it's possible that the accum cover failure has also resulted in a burned OD clutch (which would require trans removal and partial teardown), but I would first try the cover by itself and see if that takes care of it. They can also inspect the pan when they remove it to see if there are signs of clutch debris (indicating a fried clutch).
 
#18 ·
so on the later year trucks has that issue been addressed and fixed so the screw does not back out?? if you have this year model should you preevently address this as well.. loctite on screws to prevent backing out??
 
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