the cam in my 461 is a comp xtreme 588/593 with 250/258 @050 and when i lock my converter its smooth as a mouse cruising plum down to as low as 35mph with my 4l80e

everyone around my area that ive talked to still swears its gotta be your converter...

Jamie

 

Not gonna lie I'm suprised the valve body didn't change nothin... Is it possible to have a internal leak elsewhere in the circuit? If you wanna vote converter out just to make sure. I know it may be a total pita. But take your line pressure back in the tune and see if it still does it. When mine had the issue when you would back line pressure off the converter would lock up normal and when we would raise the pressure up it would start to act erratic on lock up. If it does it no matter what you do then I'd say you still have some kind of leak on that circuit and or a issue with converter itself. Also I can't recall but not sure if tcc circuit has a possibility with the check ***** being stuck in seperator plate or show irregular wear on either the check bald themselves or and oval or irregular wear pattern that could cause a leak? Not sure if you looked at that or not when installing valve body. Maybe something worth checkin..? Just trying to think of things to check before converter comes out, you send in get back and still have an issue.. As before your welcome to call me if you have any ?'s..

 

Damn, I'm sorry to hear the news man.
From everything you've done, I'm factoring out the misfire.
How hard would it be to detect a misfire on the 540? Just curious?

 

All signs are pointing to the converter at this point! :-D If it doesn't turn out to be that IDK what I'm going to do!



I am surprised the new VB, all new solenoids, and shift kit didn't fix it too! The shift kit came with all new check *****, and the old ones looked ok.

I talked to PTC again today and we agreed that sending the converter in for an inspection is the best option at this point. They can give it a good once over to see whats up. I'll be curious to see what they find. When I dropped the pan I did notice the bottom of it had a bit of black sediment in it. It was nothing crazy tho. I'm far from a trans/converter expert but it could indicate that the lockup clutches are on their way out... My bet is they are going to say the lockup clutches are deteriorating or something like that.


Meh its apart of the hobby. Luckily I don't give up easy. I highly doubt its a misfire as it runs like a bat out of hell, other then when it locks up. I guess the best way to tell that it's misfiring would be to watch the vac gauge when it happens... It doesn't move at all so I gotta rule that one out.

 

My bet is the valve body did fix it, it's just too far gone to matter. Mine took a converter too but after I changed it out and still had an issue it got parked till it was sorted out. Before it took another one. When's the last time Trans was refreshed? I'd just go thru it and have it resealed and new clutches and bands while it's out. It is like 25yrs old lol couldn't hurt if it's still stock.

 

When I pulled the trans the 1st time to install the converter, I found a GM reman sticker on the trans. Which tells me in the last 118k mi (OD reading), the truck had a trans put in. I know that doesn't narrow it down much. lol

The truck ran/drove/shifted fine before the 540 engine swap & PTC converter install. The issue popped up on 1st few drives on the new combo.

Maybe I will try and swap the stock converter back in to see where I stand. I think that would eliminate engine / trans issues and point to a faulty TC.

At any rate, here's pix of the what the pan looked like. Maybe you guys could tell me if it looks like something got cooked in there or not. The rest of the trans oil looked ok. The only concern is what was left over in the pan. Thanks again guys!

 

Alright so I swapped in the old (aka known good) TCC and the freggin thing still bucks under lockup!!!

The trans/TCC was working good behind the old engine, so that leads me to believe I'm getting engine misfires during lockup somehow. I'm mystified by this as the engine runs pretty well otherwise.

Time to take a dive down that rabbit hole I guess... I'll update again with results if I can find anything conclusive.

 

Damn, not good.

Like yours, mine runs great. I only feel the misfire at idle, otherwise its not existent.

Lookin forward to your updates.

 

Tig, have you had any engine work done lately? Like new intake or heads?

I found this last night.. It's LONNG, but really informative how he systematically steps through everything. Thought this may help you out:

4L60E Transmission TCC Shudder? No, Misfire! - YouTube

Last night I found that I had a bit of coolant weeping out under the driver side head. I'm thinking this could def cause the issue.

 

That sucks, well I hope your right on the leak causing it. I don't think it is.. But def worth a shot. Good luck man keep us posted. I still feel there is something goin on in that Trans but so tough to pin point. Ideally a gauge should be plumbed in some how to monitor pressure on lock up circuit. I know easier said than done but may be something to look into.