Transmission Slip after Cam swap

[CammedL83]

Need some help before spending tons of money.

 

Recently did the AFM/DOD delete and cam swap (BTR Stage 2) on my 14 sierra with the 5.3. This was a couple months after having my trans rebuilt. Everything seemed fine before the cam swap and after the trans rebuild. Or at least thought it did. 
 

After many hours with tuner saying that truck had idle problems, problems dying after starting then shut off then trying to start back. And problems shifting when hitting the throttle. My tuner says my trans is slipping upwards of 1000rpm in a 1/10 of a second. As well as some spark delay.
 

I find it hard to believe my transmission is messed up after just having it rebuilt. I did not upgrade the torque converter to a billet. It had a slighty better than stock converter installed on rebuild. Was done by a reputable shop. 
 

I also believe the cam just doesn’t chop as much as it should in other videos I’ve seen. I’m stuck and not sure what to do. Plz help!

Edited August 25, 2024 by CammedL83

[superdave160]

I spent about 18 months trying to get my truck to be drivable again after doing the DOD delete and installing a GPI stage 2 cam.  When I got the truck back from the mechanic that did the DOD delete, it barely ran.  If I put any load on the engine at all, the truck would surge (jerk forward and back).  I took it to two different tuners and they didn't help it much.  So, I started looking carefully at the work the mechanic did and found two things; first, the intake manifold wasn't torqued properly.  Torqueing the intake manifold is a two-step process.  The bolts are torqued to one value, then to a second value.  The shop did not torque the bolts to the second value.  After I fixed that, I still had a hissing noise when on the gas.  I had the shop install a new intake tube that goes between the filter box and the throttle body when they did the DOD work.  When installing the tube, two metal fittings must be screwed in to the tube.  The tube has nuts molded in the plastic for the fittings.  The shop screwed the fittings in until the nuts broke loose, creating an area for air to sucked into the intake that did not flow past the mass airflow sensor.  I had to replace the tube.

 

After getting all the air leaks fixed, the truck ran better but still wasn't right.  Fuel mileage dropped significantly.  The engine would die when I took my foot off the gas pedal.  Idle speed varied at least 100 RPM, and the engine shook while idling.  I bought an "OBD II display" and installed it in my truck so that I could monitor engine parameters in real time and found that the timing was being retarded way too much when the load increased.  I found a shop (Carma Performance in Nashville, TN) that performed a dyno tune, and I have my truck back again.  So, make sure that you don't have other issues that are affecting the tuning process.  Trying to tune around an air leak or some other issue will cause undesirable operation.  I took my truck to a different shop to run a smoke test to ensure that I found all the leaks.

 

Another thing to consider is that the torque converter slipping may be a symptom of another problem.  There is a lot of interaction between the engine and transmission in these trucks.  The TCM may be reacting to something that the engine is doing.  Look to see if some engine parameter is reacting at the same time that the transmission is slipping.  With that being said, does your tuner also tune transmissions?  There are a lot of improvements that can be made to the transmission tune if you haven't already done that as well.

[CammedL83]

@superdave160 thank you, I definitely will check over bolts. My tuner doesn’t do a whole lot of tuning with transmissions. One of his suggestions was to take it to dealer and have trans reflashed. 

[CamGTP]

The E92 controller is very complex being that it's all torque based. If the engine side tune is not very good, then the transmission is going to drive like crap.

 

I can't see his work obviously but part of me what to say that he doesn't know that platform very well because the engine tune must be spot on for the transmission work right. If he wants extra eyes and isn't overly proud of himself, he could post his work to the HP Tuners forums and few really smart guys over there can pick his tune apart and see what he may or may not be doing wrong.

[rlcole321]

Yes!, Tuning is the BIG key to all this, it must be done right!, I did the same with my 18 'Rado, but I learned the tuning my self, and it runs great, good low end torque and pulls good to rev limiter 6500. So find a good tuner!