schmidty77 Posted March 8, 2005 Report Share Posted March 8, 2005 I'll try to explain this as best I can...... When I try to punch the accelerator to the floor the transmission does not want to shift. And at slower speeds it seems to hesitate back and forth like it doesn't know if it should up shift or down shift. It almost feels like the truck is in 1 or 2 drive gear. Remember that I am supercharged and I was running a Whipple programmer. I have already returned the computer back to stock with no luck. Here are som theories I have been given. 1.) Transmission is shot. This makes no sense as my tranny fluid is still crystal pink and the truck runs fine in top gear from 70 mph on up. No strange noises to report of other than the rev limiter when I stomp it and get no shift. Also tranny is not running hot. 2.) Accelerator sensor has gone bad. 3.) I have a supercharger vacuum leak. 4.) My local chevy dealer service writer has said that some trucks have had a similar problem because of a glogged or dirty fuel filter. He said the truck will still rev out, but will not allow a shift. Weird Huh? Anyone else got any ideas? Ben? Zippy? Where should I start? Link to comment Share on other sites More sharing options...
chiel Posted March 8, 2005 Report Share Posted March 8, 2005 Can you messure linepressure? Link to comment Share on other sites More sharing options...
BenKey Posted March 8, 2005 Report Share Posted March 8, 2005 Have you verified the fluid level with it warm and running? Sorry if that insults your intelligence - you'd be surprised how many people don't know. No other tranny mods? What about tuning? What has been changed, if anything, in your program? Are you pretty hard on it? Crazy downshifts, etc....? Link to comment Share on other sites More sharing options...
zippy Posted March 8, 2005 Report Share Posted March 8, 2005 does it do this on the 1-2 and 2-3? Link to comment Share on other sites More sharing options...
schmidty77 Posted March 8, 2005 Author Report Share Posted March 8, 2005 does it do this on the 1-2 and 2-3? <{POST_SNAPBACK}> You got it. Like I said it runs fine in top gear. 1-2 and 2-3 are screwy. The programmer was bypassing torque management to some degree. Of course I jump on it from time to time, but after the programming changes the truck seemed more than happy to shift at a higher rpm with out letting up. It would hesitate under normal driving conditions like it was just begging to driven. Now it just doesn't want to shift at all unless I baby it. Link to comment Share on other sites More sharing options...
zippy Posted March 9, 2005 Report Share Posted March 9, 2005 it could be a valve body problem, but i'd say you might be just running into some worn out parts. it's odd that both are having problems. could be a failure in the pump also. if i had to guess you're more than likely going to have to look into a rebuild. Link to comment Share on other sites More sharing options...
schmidty77 Posted March 9, 2005 Author Report Share Posted March 9, 2005 Do you think they would blame this on the SC or should it be a warrantied item. I have my program set back to stock configurations so they should never know the truck was shifting a little firmer. I never did mess with shift points themselves. Just the torque management system was changed. Did I mention I only have 20,000 miles on the odo. That seems a bit soon for worn out parts. Don't you think? Thanks for the info Zip! Link to comment Share on other sites More sharing options...
zippy Posted March 9, 2005 Report Share Posted March 9, 2005 i think a failure this early should be fixed by the dealer. many have the radix without this issue. reducing the torque management without a shift kit might have lead to an early death though. Link to comment Share on other sites More sharing options...
schmidty77 Posted March 9, 2005 Author Report Share Posted March 9, 2005 So after I get it fixed you think I should invest in a shift kit? I've been driving it and doesn't seem that it is missing the shift as much as it's not even attempting a shift. If I keep the accelerator at between 3000 and 4000 RPM it up shifts from 1-2 & 2-3 very smoothly. The problem feels like this...... Already in 3 I punch it........truck downs shifts to 2.....truck accelerates......won't shift back to 3. Oh well. Truck goes in tomorrow. I'm going to have them change the fuel filter for the hell of it and replace the tail gate cables and have them run a tranny diagnostic. Wish me luck. Hopefully they don't end up keeping my truck for too long. Thanks again! Link to comment Share on other sites More sharing options...
zippy Posted March 9, 2005 Report Share Posted March 9, 2005 yes, i would recomend it. a radix truck works well with a shift kit to add a little punch. with that done right you won't need any torque management. Link to comment Share on other sites More sharing options...
schmidty77 Posted March 16, 2005 Author Report Share Posted March 16, 2005 I saw all the different shifting and slipping problems going on here and thought I would give the update on mine. The dealership ran a scanner on the tranny and found no problems. Some people think I might not have enough line pressure. I have a little bit better explanation of the problem after driving for a week. When I take off from a dead stop I can bring the RPMs up to 4K. If I stay on the throttle I get no shift. Let completely off the throttle and I get my shift. Then if I'm rolling in gear and punch the pedal enough to get a down shift all I get is neutral and a screaming engine. WTF! I did notice that one of my vacuum lines which has a rubber cap on it has a couple of cracks through it. Could this cause such a problem. Guess there is no harm in putting a new cap on. Anyone got any new ideas. The tranny itself seems to be fine. I want my damn shift! Link to comment Share on other sites More sharing options...
BenKey Posted March 19, 2005 Report Share Posted March 19, 2005 When you take off from a dead stop, do you mean flooring it? You get no shift whatsoever, or does it come after a long delay - foot still in it? Does it feel like the engine loses power at the same time? Link to comment Share on other sites More sharing options...
schmidty77 Posted March 21, 2005 Author Report Share Posted March 21, 2005 When you take off from a dead stop, do you mean flooring it? You get no shift whatsoever, or does it come after a long delay - foot still in it? Does it feel like the engine loses power at the same time? <{POST_SNAPBACK}> Yes, flooring it. It will shift after delay, but only if I let off the throttle or hold it in position at a reasonable RPM between 3-4K. Shifts quicker if I let off the throttle completely and let the RPMs drift down. I don't think it plans on shifting anywhere after 5200 RPM and then my SC belt squeels from slipping. The engine doesn't appear to loose any power. I would say I get to about 30mph at 3500 RPM in first gear and then the tach shoots up real quick to rev limiter because I've maxed firt gear out so quick. I've sent an e-mail to the tech @ Whipple to see if they have ever encountered such a problem in their history. If not I guess I'll let the dealership take a closer look at the tranny. Nobody seems to know what the hell is going on here! Link to comment Share on other sites More sharing options...
smithl3 Posted March 21, 2005 Report Share Posted March 21, 2005 When you take off from a dead stop, do you mean flooring it? You get no shift whatsoever, or does it come after a long delay - foot still in it? Does it feel like the engine loses power at the same time? <{POST_SNAPBACK}> Yes, flooring it. It will shift after delay, but only if I let off the throttle or hold it in position at a reasonable RPM between 3-4K. Shifts quicker if I let off the throttle completely and let the RPMs drift down. I don't think it plans on shifting anywhere after 5200 RPM and then my SC belt squeels from slipping. The engine doesn't appear to loose any power. I would say I get to about 30mph at 3500 RPM in first gear and then the tach shoots up real quick to rev limiter because I've maxed firt gear out so quick. I've sent an e-mail to the tech @ Whipple to see if they have ever encountered such a problem in their history. If not I guess I'll let the dealership take a closer look at the tranny. Nobody seems to know what the hell is going on here! <{POST_SNAPBACK}> Does the tach shoot up because you are slipping, or is it because you are just maxing out first gear? I am having similar shifting problems. I having unsuccessfully tuned it out it is clearly my pack and band at this point, since everything else has been worked on. Is this still a stock tranny without servo's or shift kit? Link to comment Share on other sites More sharing options...
schmidty77 Posted March 21, 2005 Author Report Share Posted March 21, 2005 Does the tach shoot up because you are slipping, or is it because you are just maxing out first gear? I am having similar shifting problems. I having unsuccessfully tuned it out it is clearly my pack and band at this point, since everything else has been worked on. Is this still a stock tranny without servo's or shift kit? <{POST_SNAPBACK}> I'm sure first is just maxed out because I can feel the gear slow me way down immediately when I let off. Kind of like driving in D-2. Tranny is bone stock. I sorta figured it could handle 5-6 lbs of boost without a mod. After all it is my every day driver. And with the snow and traffic here lately I have't exactly been able to get on it. Link to comment Share on other sites More sharing options...
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