Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
17,496
156
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Phoenix Az
I know most of you probably saw my post in my build thread of the new converter Mike and Dave were gracious enough to let me try out but i figured id start a thread because.... well..... this trans just aint so simple as days past lol.

Im not going to lie, R&Ring the t-case and trans in this truck is NOT going to be any kind of fun on the ground. Frankly, you will have to be extremely creative if you do and have a few friends around. Then hope you dont smash lines or connections when re-installing everything! the t-case its self (being auto 4wd) is heavy as hell!!

anyhow, onto the converter. Its a Billet triple disk DK converter so 1900-2200rpm stall speed. that would seem high for this truck but its not. The stock converter is fairly tight. i didnt get a chance to really stall it but id say it was 1600-1800rpm stall. with 10 speeds and this engine making torque so low, tight works good. i honestly wonder if GM did that as a way for better coupling when unlocked. the problem i didnt like is there was a slight dead pedal with converter unlocked and letting out of the throttle, then rolling back in. There is also a decent dead throttle when hitting the throttle from a stop (for instance, wanting to accelerate quickly to pass someone because you are in the wrong lane, not racing them.... deeeeeeeeeeeefinitely not racing them....:D). With this converter, you still have that dead spot from a stop but its not as bad. you gain a little more acceleration and then the power comes in quicker. there must be fuel limiting or MAF limiting happening to keep from packing up the DPF.

the coupling of this converter is better than stock as well. Under stock power, there is a decent rpm drop under wot every time a gear shift happens vs stock. i would say about 1-200rpm more so the stock converter is just not coupling as well but does get the job done under stock power. Sadly i didnt get the chance to run the stock converter under higher power from the derringer but most of you know its not going to improve, its only going to get worse. ive seen a video of a deleted and tuned 10 speed jsut sitting on the 3-3200rpm mark when he stomped it from a stop as it shifted till the converter finally locked. From what i could tell, it was not locking up till way past what stock usually is (wot in normal mode from a stop starts you in 2nd and on the 2-3 shift, converter locks). This one has no issues locking up when it should, even on the derringers lvl 6. i found out when i needed to again make one of those lane changes with a guy next to me at a stop light so i could get to my favorite lunch spot :D. traction control off, stabilitrack off, no boost launch and stabbing from a stop broke the tires loose at the 2-3 shift and converter locking. enough the back end actually went sideways. no large plumes of smoke or thick black marks but tire screeching and some rubber on the road. Granted, this isnt like my old truck but i will give it credit for how quick it gets out.

under towing conditions, coupling is amplified between the stock and this converter yet again, the stock converter seems to be on edge of not enough coupling so adding more weight behind you is like adding more power. Stock does ok till you hammer on it, even under stock power.

Now a couple things. This converter REALLY messes with the adapts of the TCM for lock up and release. Sadly, we couldnt get adapts prior to the converter change due to a software issue, but if someone has a chance to pull that info on a 100% stock truck, id really love to compare.

With the batteries disconnected and new converter in, it seemed like the truck went into a fast learn on the first drive. upshifts were kind of stiff and quick on the first key cycle, then down shifts did the same on the second key cycle. the converter was very quick and stiff on lock up. it was a good kick in the pants every time it happened. it took about 200+ city driving miles of continuously varying throttle inputs, key cycles, and locking/unlocking of the converter to finally start getting it back to a smooth stock lock up. At this point I have a very very small amount of "bump" i feel on lock up but every day i drive it, it feels better and better. there is also some tip in/tip put/change mind parameters that also affect lock up and how smooth it is so ill be doing more of those to see if it smooths out. and to add, just like the older gens, tow/haul has to learn this and now so does "off road" mode. so 3 modes total.

i know at this point, im getting more power through the trans as well as the tuner being on there. the stock trans isnt going to be happy for super long if i drive like a jackass. we really need tcm tuning as the progression of more electrical data comes in. its going to take a combo of tcm and hard parts to make this thing work well and last under high power.
 
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buick455

New member
Sep 26, 2010
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Great write up. I'm very excited to see what Dave and Mike come up with on these transmissions. Do we know what the line pressure is doing on these just out of curiosity?
 

KyleC4

Tech
Dec 30, 2016
371
13
18
Bay Area
You say dead pedal James. Was it same stock, with new converter, and with derringer ? Different levels in derringer? Just wondering how much the tuner gets into the torque management software or if you feel they’ve (Banks) have kind of left it alone. Great write up though. I’ve looked at those transfer cases and they are indeed robust lol. Look like they’d weigh as much as transverse mounted trans.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
17,496
156
63
Phoenix Az
Derringer has no affect on the dead pedal. It’s simply a map and fpr fooler like the old duramaximizer (that was just a fpr fooler) but it will derate it’s self if egts or other limiters get too high based on info from the Idash/data monster (I think, seems viable anyhow)

I don’t know that I’d really want the dead pedal to go away unless it does not induce more particulate into the dpf. That would probably take actual ecm tuning to test and see
 

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