Fallen.One05

iTrader: (3)

Ok, so while cruising between 60-70mph... (running around 2000 rpm)... if i go to give it a little throttle it'll kick up to say 2800 rpm then kick down to 2000 and go... (after the truck warms up a bit)

Its been doing that ever since the sprag went out.

The other day (while on a longer than normal drive)... it progressed to where I didn't even need to add throttle... it just randomly started going from 2500 rpm...to 2900 rpm.... back to 2000 rpm. (with no throttle added...just cruising) (Have not driven it since... so not sure if it still does this or not)

However, if i keep it under 55 or so... I notice nothing out of the ordinary... yet.


After reading up on "similar" issues... it sounds like the TC is locking & unlocking...

ANY idea what is up? Kinda thinking something maybe with the torque converter?
Tune maybe? (assuming my pcm was flashed when i had the sprag replaced)
Something else?

Thanks guys.

Rhino79

iTrader: (7)

Misfires or the pcm thinking its misfiring will cause a lock/unlock condition. What converter is it?

Fallen.One05

iTrader: (3)

Its a TB converter

LS1TRUCKGUY

iTrader: (7)

im assuming you did not have the truck retuned after installing the tb converter? sounds like your tcc lockup setpoints need adjusted. mine did the same thing with the stock converter until i had it retuned. also may be picking up some knock/misfire as said above.

Jeff_383

Could also be the lockup min/max tables need to be set higher to hold the lockup with the higher stall. Had to do this with mine. Wouldn't think the TB stall would be high enough to cause a problem, but who knows.

05gmcsierra

iTrader: (3)

had the same problem with my truck.. at first it would do it only while going uphill.. then it started to do it just regular cruising at around 75.. felt like converter would lock and unlock... and this was on my way to the dyno.. guess what she didnt make it.. Justin(blackbear) couldnt get converter to lock in 2nd to tune it.. on my way back home while getting on the fwy tranny blew my 2-4 band... drove two hrs in 3rd gear back home.. when i finally rebuilt my tranny one of the plastic accumulators was broken.( belive 1-2) if that exist..lol... i say try to get it fixed with tune.. if not something might be wrong with tranny... btw mine would jump from 2200rmp to like 2600.. so not at much as urs...

Fallen.One05

iTrader: (3)

What about shift solenoids?

baSICK5.0

iTrader: (1)

mine does this from 40 to 55 mph. once its warm it isnt bad but cold and all the way to work and all the driving I do daily...it dirves me nuts. Im getting to flashed soon to fix it.

built408

iTrader: (10)

Do you have any way of logging it when this happens?

Was anything else replaced or repaired with the sprag?

It definitely sounds like a tcc issue, either with the converter itself or possible tune problem.

Any codes set?

If I had to take a guess, I would say it's in the tune. But it could be the converter, solenoid, seal, brake switch, misfire, etc. Hard to tell without driving it. Your always welcome to come by and we can go for a drive.

Fallen.One05

iTrader: (3)

I don't have anything here to log it... no... but ive been looking into a retune from Justin@BB for awhile anyways... could just do the data logging thing...

Nothing else was replaced when the sprag went out... and i havent checked for any codes yet. (will tomorrow). My ses light has been on for awhile..due to a evap thing... (so i dont know if any "new" codes are being throw..)


Here's an update...
Well, for the last week or so...everything has been acting normal... minus a long/delayed shift into OD.... (it'll "half shift".... then a few seconds later... shift the rest of the way)

Also, whenever it does this "surging" issue (still does it... did it tonight)... if i go to actually accelerate, something grinds or rubs or vibrates together inside the tranny... no clue what, why, or how... just know that i "feel" it... rather than hear it.

That narrow the issue any?