Ive read before about the 2-3 shuttle shifting and I just want to confirm that this is infact what Im feeling. This was a very very minor issue when I had 33'' tires but it seems to be worse now that I have moved up to 35''s. Under very light throttle between 20kms and 40kms I feel a light stuttering. Is this what you guys are talking about? What is the fix? I have a VB done by a local tranny guy who does all of DDPs trans work and some for Piers as well so I am confident the VB is setup correctly. Is the transducer and solinoid the best place to start?

 

Mines an indeciceveness (sp?) between 2nd and third at light throttle....cant pick a gear. I've tried a lot of things and cant get mine to go away...DTT Shift Enhancer eliminated the 1-2-1-2, but didnt eliminate the 2-3-2 shift junk....i put in a new solinoid with the trans parts, tried a diff 3rd gear spring,....still cant get it to go away....so i'm hopping you get a good solid answer!

 

I have replaced the solenoid and transducer, added the shift enhancer, cranked the line pressures up a bit and still have the 2-3 hesitation under light throttle with Smarty moderate TQ management loaded. It is definitely better on stock or mild TQ management but too little throttle position and it is noticeable. Medium to heavy throttle is fine.

As near as I can tell this is going to take some rework on the shifting circuit, second gear apply piston, and more pressure. It feels like the the band is releasing but the direct clutches are not applying fast enough causing a slip or cut loose. I am guessing the pressure is low enough that it is being used to release the band and not quite enough left to apply the direct clutches as fast as they should.

I think it is fixable without tearing the trans down but will see how it works when I get to it.

 

I am already running a VB with alot of line pressure so Im good there. Im goin to call TPS next week and see what he says. Ill probably head out there next Sat and let him take it for a drive.

 

So as far as the DTT Shift Enhancer goes does it make enough of a difference to make it worth buying? How much was it? How hard is the instal?

 

I just had the whole trans done with a shift enhanser, I does draw out the shifts better but under light throttle will still do the 232 shuttle shift every once in a while. I tried a smarty out today with one of the beta programs and it completely took care of the shuttle shift. My trans won't shift to second until 20 mph and then won't shift to third until about 35 mph even under light throttle. I think the smarty was some how controlling the shift points.

 

Too much line pressure at low speed is actually the problem. The truck thinks - based on line pressure - that your throttle position is much more than it actually is and so it thinks you want to down shift.

Just today, we installed a "test" VB from DTT in my truck. So far it seems great. I don't have all the technical terms of how it was done, but basically Bill at DTT was able to set it up so that it's like an RV set up but then at WOT, the pressure jumps way up so it's more like a race set up. A couple more days of driving in town and we'll know for sure, but it might be the baseline for eliminating this headache everyone deals with.

 

If too much line pressure at low speed is the cause then why do so many trucks with stock transmissions have the same issue? Its not that I disagree I am simply asking? I know very little about how an auto trans works. I had the same issue before the VB was done. It wasnt until I put the 35'' tires on that it became an issue worth fixing.

 

Ok so I was out drivin around today and decided to shift manualy from a stop to see if it still would do it. Of course it didn't. The weird part is now the issue is 90% better. I can hardly notice the shuttle on the 2-3 shift now if it even does it. Why would shifting manualy have any effect on it??? Anyone got any ideas? Would me running 35'' tires and not having the ecm programed for them make any difference? Can I borrow a programmer to adjust for the new tires or would it VIN lock the programmer to my VIN?

 

There are two different things being talked about. The shutle shift is a negative trait of the 48re. The smarty and other programers will make the shuttle shift better. The other situation is when torque managment is being reduced or eliminated the ecm is being told the truck is already moving faster then it is, So the trans is shifting as if the peddle is to the floor. Even if its light throttle.

I dont know how to fix it I just know it bothers me ALOT. I have talked to dusty about it and it seems to be one of those things.

Hopefully Marco and Company will figure a way to fool the detent while also deleting the torque managment.

 

I dont have a programmer so for me they have nothing to do with my problem. I dont expect i will ever buy one. I plan on sticking with my Quad box as I am very happy with it. If I could borrow a programmer to reprogram my ECM for the new tires without VIN locking it to my VIN then I would use it for that but thats all.

 

I had the ECU flashed for the new 35'' tires. Now it is really bad. Since the flash the shuttle shifting is happening all the time under light throttle and now under heavy throttle Im getting a flare on the 1-2 shift that really sucks. It never did this before the flash was done. Im going out to DTT to talk to them about the shift enhancer tomorrow and if that doesnt work I'll head out to see Steve at TPS to have him drive it and see what he says. I am hoping its as easy as installing the shift enhancer.

 

So hows the test VB from dtt working out?

 

Hey OmahaRam, any results to post yet? I have the same issue with my truck and still looking for an answer. I have a Valve Body on order from Goerend butr i'd hate to install it and it not solving the issue. This was the only reason why I ordered it.

 

With stock internals, Dave's VB will probably fix it. When I had his VB I never had the issue. the problem I ran into is that I when I had my internals upgraded Dave's VB was way too harsh with the extra clutches and less clearances.

As far as the VB that I last had put in from DTT, it no longer does the 2-3-2 thing. At first when it was installed it had a flare from 2-3. That was fixed with a spring change. The only issue I have now is that it sometimes shifts to 2nd too soon at light throttle. that should just be a TV adjustment but I havent' gotten under the truck to tweak it because we've had nasty weather here and are expecting more tonight.

So as I understand it, the new VB is sort of a hybrid between their rv and the race. It keeps pressure low at light throttle and then ramps it up quickly at heavy and WOT.