Shifting Funky

[jlayne]

Ok my truck has got me stumped, not sure where to start looking. When my truck shifts from 2-3 the truck jerks about 3-4 times. While it is doing this the tach bounces up and down about 300 to 500 rpms. It will stop this as soon as you let of the go pedal. I cant decide what is causing this. If I'm just poking along or at full throttle it won't do it but at part throttle it bucks like crazy about 2 out of 5 times. I have been told over at the other site that it is the motor possibly something related to the IPR or some other sensor. i find that hard to believe because it only does it on 2-3 shift, I think it is something in the transmission or torque converter (hopefully the second because I want a new one anyway and I'm too cheap to buy one till this one is fried) It gives me no codes at all. The only programming I have on the truck currently is a evolution. Thanks

 

[Dieselmaster]

J,

Are you sure its the 2-3 shift and not the TC locking up??

I would lean more towards the Tranny since it happens only at the one point...

 

[jlayne]

well i'm not sure if it is the TC locking up... but if thats the case, it locks then unlocks and locks a couple of times... I have also thought this several times... just not sure how to go about fixing

 

[Mike]

Take the evolution off, put it back to stock and drive, see what happens.

 

[Dieselmaster]

For it to be jerky and cause/effect the RPM's I would think that it would be the TC... because a shifting with the TC unlocked wouldn't or shouldn't be felt as much...

I would lean towards the TC but if it were it would likely throw a code... You could hook up a TC lockup light and watch to see if the jerkiness corresponds with the lockup..

 

[Dieselmaster]

Mike,

I jumped ahead... typically that would be the first thing I would recommend...

Go back to stock and see if it's programming that is causing the problem...

 

[jlayne]

It has never done it with the evolution off... but I'm not sure its a programming issue... but I do need to send it to get the software updated i'm still runnign revision 13 (they are in the 20's now)

 

[Dieselmaster]

J,

Some tuners exagerate a problem that is already there and just can't be felt at stock levels....

But if it doesn't happen with the tuner out then I would lean towards the tuner and its programming... I definately would check with the maker for an update or alternative programming.

Do you have a shift kit or FTvalve body, that might effect shifting?

DI changes the programming for trucks that have shift kits because the shifting can be very harsh with the two in conjunction.

 

[jlayne]

the tranny is stock, I think but it really bangs through the gears so who knows (i bought this truck used, i'm still trying to figure out if it has stock injectors also... if they are they smoke more than any other stockers i have ever put a wrench to), it could be the tunner, but I think it might be something like what you said that it is exagerating a existing problem.. it doesn't shift sloppy on 2-3 but its not very tight either at part throttle, at full throttle it feals like its goint to tear the u-joints out, it barks my 33's... I will call edge and talk to them or atleast get put on hold. I might pull the pan this weekend to see what I can find.. hopefully not metal shavings

 

[Dieselmaster]

Originally posted by jlayne
the tranny is stock, I think but it really bangs through the gears so who knows (i bought this truck used,

It sounds like it has a shift kit... My truck stock without the shift kit would have never barked the tires when shifting...

Now with the kit I can bark the 37's jumping into 2nd...

 

[Mike]

Do you have a trans temp guage installed? At least pull the dipstick and see if it smells burnt.

 

[jlayne]

it has guages in it.. the hottest i have ever got it was around 200 pulling my car hauler through the mountains.. most of the time it never gets over 115. I'm going to check out the fluid tomorrow, I did think of something though the truck doesn't do the funky shift while its cold at all.. only when hot (still not all the time) I'm leaning toward something mechanical.. Its been doing this for about 6 months now and its starting to get annoying.

 

[upnorth]

How about a bad injector?

 

[jlayne]

ran my truck today on my buddies t-tech tranny flusher... made a big difference, hardly bucks now... might hook it back up in a month or so... it must have had some crud in it or something