i know this has nothing to do with the 6.5 but i posted in the 4l80E section and didn't get much help there. so here goes. lately i've notice that when my truck is shifting from 2nd to 3rd it seems to being the shift and then hesistate in between the gears and then go into 3rd. its weird as it only does it at low acceleration speeds. if i stomp on the go pedal it doesn't do this and it will shift from 2nd to 3rd with no apparent issue. i don't think its a trans problem as when a trans begins to slip more pedal would make it slip more not less. i don't think my filter has been changed since the truck was new. its got almost 160K miles on it. any chance i could've gotten some junk in the pan and its causing a solenoid to stick at low acceleration? also what is the capacity of the trans pan. if i change the filter how much and what kind of trans fluid do i use to fill it back up? thanks everyone.

EDIT: i do have mud terrain 245/75/r16 tires on the back with very aggressive tread. could this be a factor as it either wasn't noticeable or was not even present before the tires were switched to the M/Ts.

I recommend you seek out a competent & ethical transmission specialist or Gm dealer for a diagnosis. Accurate information is what you need,now. You should get it right the first time for financial reasons!!!

would a trouble code from a trans show up as SES? i'm guessing that this would not cause a SES light. the only think i find weird is that faster accelaeration(or more pedal in general) makes it shift fine. it drives fine and shifts good except for this one small thing. i'm planning on changing the trans filter today, maybe that will help? i've got no knowledge of auto transmissions.

Hi Dave, changing fluid/filter can do no harm, and might just clear it up, so why not? Other than that, 4doortahoe's advice is sound....if that doesn't straighten it out, get it fixed before it turns into a bigger problem.....

trans issues are expensive. that i'm aware of. maybe a solenoid going bad? anyone know the resistance value of a good solenoid(2nd gear to 3rd). i'll check the one i've got with a multimeter when i pull the pan to change the fluid. i've heard that you can get to them by pulling the pan. is this true?

When you pull the pan you will see the shift solenoids. Any time I have had to replace them they would set a code. The SES light was not on, but codes were stored in memory. They remove with a spring clip...

thanks chris. would the local autozone/advance auto be able to pull up the codes with an average OBDII scanner? or would i need something like a tech II?

EDIT: does this sound like a bad solenoid chris? i would figure if the trans was slipping wouldn't faster engine RPMs may it slip more and not less?

Yes, every autozone i have been to has been able to read obdII codes with their scanner so you should be able to see if you have any transmission codes stored in the computer. Get the computer scanned and change the fluid/filter..it could be a good idea to flush the trans cooler as well if you have any debris in the pan, its a $10 preventative maintenance that is pretty easy to do..Then if you have any codes post them up.

first of all...what are sex light diesel guy, second of all...i use gm dex VI in my tranny but someone else will no doubt recommend using some kind of synthetic...depends on what your doing with your truck i guess...but dex VI is probably the cheapest way to go and still be way over OEM specs

Sex lights are just aftermarket lights that i have mounted inside the cab of the truck, pointed at the floor to make finding clothes alot easier when its dark:D, and attached to a switch so i can toggle them on and off.

are the solenoids expensive? if i'm gonna do the filter i want to do the solenoid if its going bad as well.

chrisk1500 what were the symptoms of a bad solenoid? anything like what i'm getting?

depends where you go i guess...you can get a combo of both shift solenoids for ~$20+shipping off ebay, never really looked anywhere else but im sure that tranny shops would be a little more expensive and dealerships being even more i imagine..

Symptom I had was a 'no shift' and a 'random shift' problem. Never had a soft shift problem....I am not saying the solenoids are your issue - just telling you how to replace them if the scanner shows them as being the problem...

Has the wiring (connectors,etc.) been reviewed?

How's the fluid level and color?

Hey Dave,
I have heard good things aout this guy in the North East forum. Don't know if you are close to West Haven but he's a supporting vendor also. Maybe if you are too far away you could shoot him a PM for advice.
http://dieselplace.com/forum/showpost.php?p=1607758

alright. got back from advance auto. apparently the trans was down 1/2 a quart on fluid. fluid is red and does not smell burnt. which is strange because i filled it up before. it was down almost a full quart a while back. leaky cooler line perhaps?

no DTCs were present and the scanner said "system passed". got a new filter that i'm going to install. any other places it could be leaking from? does this truck have more than 1 trans cooler? theres two coolers in front and i know one is the oil cooler but theres also a trans cooler built into the radiator is there not? so what is this other one? if looking at the front of the grille its the one on the passenger side. power steering cooler?

I had a car leaking trans. fluid and never a puddle under it. It was a line. It only leaked when driving. You'll have to get under it and look for the leak if it's hidden. Leo

1/2 quart low would not cause problems.

it wouldn't cause my interesting shift issue? seemed to be shifting better on the way home after i added fluid. i don't see what else it could be. no DTCs mean the solenoids aren't bad. and its intermittent and only under light acceleration. heavy acceleration its not present. if it was slipping heavy acceleration would make it slip more not less, at least that what i've been told.

If the second cooler your are talking about is about 4" wide it is the PS cooler.

So did the adding of the oil clear up your issues Dave?

If i were you i would just do a routine maintenance on your transmission now that you are thinking about it..Change the filter and the oil and maybe run a bottle of the transmission Seafoam through it for good measure(and maybe put a drainplug kit in for future help, its so easy and helpful!). Believe me when your transmission starts acting funny you wanna do as much preventative maintenance as possible, iv had my fair share of tranny issues:((details in signature) and it is not fun taking it out that first time let alone a 5th:mad:!