Need some thoughts from you expert trans guys plz.

My '99 Z28 LS1 4l60e in my 57 chevy conversion has a transgo shift kit and is all stock, including converter, other than a deep sump pan. It has been working great with converter lock up functioning fine and good solid up shifts. Today I noticed that when I manually select any gear from a stop (1,2 or 3), accelerate and let off the throttle, it acts like it has been shifted into neutral....no motor drag at all. It still acts completely normal under regular "D" selection starts....even WOT acceleration lights the tires on 1-2 shift and all other shifts are super solid...?? Is this an indicator of major troubles coming my way, or is there something I did at the transgo install that could need attention..? Could it be a PCM issue..? I only have about 600 miles on the install and the drive line has about 17000 original normal miles. Fluid is full and clean.

Any suggestions on what to try..??

Thanx in advance guys..! DK

 

So you have no "tranny braking" effect? Damn, I had the identical problem years ago with my FLP Level 4 4L60E, but otherwise the tranny worked perfectly and crisp, just when I took my foot off the gas in any of those gears or if I were to manually downshift while slowing down with my foot off the brake from any speed, downshifting did nothing, it would just coast like it was in neutral. But as I came to a stop it would take off again normally and shift like it was brand new while accelerating through the gears.

I will ask my tranny guy if he remembers what it was, but he took it apart and found whatever it was, I just have no clue. Sorry I just don't remember so I can't tell you right now, but I'll check tomorrow.

I could be wrong, but for some reason I'm thinking it was that strap thing that goes around the tranny on the inside, I think it was cracked and pressure was lost if I wasn't under acceleration or some kind of steady gas pedal.

This thing. (got this photo from the performabuiltautomatics thread)

 

No it would not be the band either the overun clutches are burned or the lower hub on the input sprag assemblies teeth have broken off , The band is second and 4th gear .

 

Mine starting doing it, a few months ago. Then one day it went away, then about a week ago it would after I went WOT a few times be normal. Now it does exactly what he is describing. It's also an FLP level 4, am I screwed?

 

What can crack, causing a loss of line pressure when you are not on the throttle?

I know for sure that nothing in my tranny was broken, no gears, no teeth on anything. It was a very easy fix and cost me next to nothing. He charged me $80 labor. I just can't remember what was replaced inside. He did it in half a day.

 

Thanx for the responses guys.

Man, I was hoping it was not a major "gotta pull the tranny" problem. I appreciate the answer from Performabuilt and obviously respect their opinion, they have a ton of experience, but if I only had to drop the pan and replace something simple it would be awesome (I know this may be wishful thinking). Just seems odd that it works perfectly under all other conditions..!! The absence of any noticeable debris in the fluid or odor leads this amateur to think that it may be something simiple. Obviously, I dont want to have a total failure when I am hundreds of miles from home either....that would suck..!! LS6427, If you find out anything more, please let me know and thanks for your replys..!!

Still worried here, but driving....lol DK

 

Waiting on him to call me right now.

 

If you get a chance, post a pic of the ol girl.....I'd like to see yours.

 

https://ls1tech.com/forums/showthrea...ir#post8010692

Scroll down a bit and you'll see some pics I took of a '57 Bell Air that we have a nasty 4L60E in. We'll be running it in a Muscle Car Challenge race in a week or two. It runs mid 7.xx's 1/8 mile!

Cool car man!

g

 

Here is a few pics of my 57.......tranny still worrying me...lol

DK

 

Hey, my tranny guy said it was the "over-running" clutches. The clutches that keep the tranny from spinning in the other direction when you are maually downshifting the tranny or when it does it by itself.

 

Thats what I said earlier and makes sense

 

man those are some nice cars! Thanks for the pics fellas!

 

Guess that means I have to pull it out......that really sucks.!!

Thanx for the replys..!! DK