strange flare in 2nd gear

[oldred95]

For a while now my truck has been acting strange in 2nd gear under hard acceleration. It only does it at or near WOT in 2nd from say 3000 rpms and up and it doesn't always do it. Basically it will become loose and the rpms will flare up and sometimes go up and down somewhat and just kinda hang there and then shift on into 3rd gear and when it shifts its as firm as ever so I'm almost positive its not slipping. Its almost like the engine is overpowering the sorry excuse for a converter its got and just spinning up and not being coupled to the tranny if thats even possible. Has anyone ever heard of this happening before?

[performabuilt2]

sounds to me that the 2-4 band is failing

[oldred95]

sounds to me that the 2-4 band is failing
If it was going bad it would do it everytime and this only does it when it feels like it and the shift is firm everytime.

[Tbi-MAX]

sounds like the converter is slipping... i hadnt wot mines yet, but mine has a slight feel on 2nd shift also, but it shifts firm in all gears, i was told by 2 mechanics my stall converter?

is yours making any noises?

[oldred95]

If it was gonna slip 2nd gear it would do it when it shifts into 2nd when it drops from 5k rpms to 3000 or so. That point in time puts a hell of a lot of stress on the clutches, more so then WOT from 50 mph and up in 2nd gear when the band has already engageds and holding fine.

[performabuilt2]

well you either have a bad 2-4 band as i have stated or a leaking servo or you have a problem with the EPC not raising the pressure to boosted to hold the gear when it changes you need to put a set of line pressure guages on it and see what the pressures are this will tell you alot at WOT it should be around 220 give or take 10 psi....if it is lower on the 1-2 shift then you have either a leaking seal in a servo or the EPC either mechanically or electronically is not doing its job the pressure regulator valve could be getting stuck to.....the first step in this is to get some guages on it and read the pressures
1. get a static reading should be around 100 or so
2. run the vehicle at 3500 and shut the key off this will give you the max output of the pump should be around 220-250 or anywhere in that area
3. run it through the gears at light throttle and record the pressures
4. do the same thing at wot and record the pressures
there will be a slight drop in 3rd but it should recover the drop is due to the numerous hydraulic actions that are happening in the trans

[oldred95]

I've been told by a guy who knows that the 4L60E is mechanically regulated at around 180psi max. I can datalog the transmission and I probably should, I just thought I'd ask here first.

Can someone explain torque converter ballooning to me?

[ariansyukon]

My Yukon does that when I'm pulling my boat out of the water only when I put the shifter in 2nd. I can take off in 3rd or overdrive and it shifts throughh fine

[oldred95]

My Yukon does that when I'm pulling my boat out of the water only when I put the shifter in 2nd. I can take off in 3rd or overdrive and it shifts throughh fine
Thats called 2nd gear start. Came about with the 4L60E to help with low traction winter driving so you can start in 2nd and not have the gear reduction to spin all over the place. That is normal.

[ariansyukon]

Thats called 2nd gear start. Came about with the 4L60E to help with low traction winter driving so you can start in 2nd and not have the gear reduction to spin all over the place. That is normal.
I thank you very much for that .I guess now I wont be puzzled when it does that

[oldred95]

Went for a drive tonight and was cruising at 60 mph in OD and floored it, jumped right to 2nd and everythign was fine, ran it up to 5200 and no flaring, shifted to third and let out on the throttle some and then went back down on the throttle and it pulled to 3500 and then it started flaring in 3rd. All shifts are firm, no slipping. Its gotta be the converter being over powered. I know the converter is not stock, I've looked every inch of it over and its not marked with any sort of common part number, brand name or anything.

[loco2355]

Could it be in the PCM tune? I had a mail order tune and had that same problem. When I went to another tuner the problem went away.

[oldred95]

Could it be in the PCM tune? I had a mail order tune and had that same problem. When I went to another tuner the problem went away.
I'll know more this afternoon on that.

[94Blazer383]

My truck was doing something similar in third gear wide open throttle. It ended up being in my tune. After I got my wide band I was able to get rid of it. She pulls smooth now. If you have a wide band check your AFR at wide open throttle when this happens.