2-3 WOT shift problem
Thread Starter
On The Tree
Joined: Feb 2003
Posts: 108
Likes: 0
From: MANCHESTER UK
2-3 WOT shift problem Fully rebuilt 4l60e with Alto race kit by a pro.
All shifts set at 6500, launch in D
testing ran mid 11.40's 3 runs. All ok. best times ever.
3 months later at race meet(nothing changed), in qualifiers won't go into 3rd. hitting rev limiter at 6800, lifted and floored it again and went into 3rd, ran 11.60.
It wasn't slipping as it was still pulling hard until it hit rev limiter.
2nd run same again.
dropped the shift point to 6200 for next run, same thing happened.
Out 1st round due to same problem.
unable to test since then. Track only car.
Checked ATF level, ok, drained it, no crap in it, fluid clean.
Any ideas???
2-3 shift solenoid?
I converted it from TCS to non TCS throttle cable a while ago, removed all TCS stuff etc. Can't be this, can it?
Log of run below, starts at about 3250 frames
All shifts set at 6500, launch in D
testing ran mid 11.40's 3 runs. All ok. best times ever.
3 months later at race meet(nothing changed), in qualifiers won't go into 3rd. hitting rev limiter at 6800, lifted and floored it again and went into 3rd, ran 11.60.
It wasn't slipping as it was still pulling hard until it hit rev limiter.
2nd run same again.
dropped the shift point to 6200 for next run, same thing happened.
Out 1st round due to same problem.
unable to test since then. Track only car.
Checked ATF level, ok, drained it, no crap in it, fluid clean.
Any ideas???
2-3 shift solenoid?
I converted it from TCS to non TCS throttle cable a while ago, removed all TCS stuff etc. Can't be this, can it?
Log of run below, starts at about 3250 frames
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
This sounds exactly like a worn 3/4 clutch.
Sorry, but various pro builders have told me that the thin frictions and steels in the old Alto kits don't hold up long. IIRC they come with a thin backing plate; combined with high line pressure, the whole assembly "cones" ruining the frictions.
I suggest getting the trans rebuilt with BW HiEnergy (Green) 3/4 frictions. Use the thickest apply and backing plates, and 7 or 8 frictions. I document the details in post #2 here:
https://ls1tech.com/forums/automatic...some-info.html
Lots of members have successfully used those combos.
Obviously you also want either a complete shift kit installed or at least a .490/.500 boost valve from e.g. Transgo or Sonnax. The Sonnax is better as it has o-rings to prevent leaks and holds the pressure better.
Sorry, but various pro builders have told me that the thin frictions and steels in the old Alto kits don't hold up long. IIRC they come with a thin backing plate; combined with high line pressure, the whole assembly "cones" ruining the frictions.
I suggest getting the trans rebuilt with BW HiEnergy (Green) 3/4 frictions. Use the thickest apply and backing plates, and 7 or 8 frictions. I document the details in post #2 here:
https://ls1tech.com/forums/automatic...some-info.html
Lots of members have successfully used those combos.
Obviously you also want either a complete shift kit installed or at least a .490/.500 boost valve from e.g. Transgo or Sonnax. The Sonnax is better as it has o-rings to prevent leaks and holds the pressure better.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Yes, the friction/steel combo becomes concave due to the thin/weak backing plate, especially with high line pressure.
When you back off, the trans shifts under less power letting the frictions grab and then hold the full power later. Think of your tires - once they spin you have no traction until you lift a bit and let them grab again.
Sonnax makes a updated input drum that holds one more friction, but more importantly has a very solid bolt-on backing plate that eliminates any chance of coning.
Also, you should have your line pressure checked. WOT should be around 225psi. Some builders think "more is better" and tweak the Pressure Control Solenoid to exceed that value which increases the chance of coning.
While I answer many/most 4L60E questions here, I have limited experience with other people's transmissions and am certainly not a pro builder. I assume you have checked the obvious such as the fluid level and even tried overfilling by 1/2 quart.
I also always recommend connecting a pressure gauge to verify it is not too low or too high. The model "ATD 5550" is expensive and hopefully readily available in the UK. I suspect all trans shops and many auto shops have one.
When you back off, the trans shifts under less power letting the frictions grab and then hold the full power later. Think of your tires - once they spin you have no traction until you lift a bit and let them grab again.
Sonnax makes a updated input drum that holds one more friction, but more importantly has a very solid bolt-on backing plate that eliminates any chance of coning.
Also, you should have your line pressure checked. WOT should be around 225psi. Some builders think "more is better" and tweak the Pressure Control Solenoid to exceed that value which increases the chance of coning.
While I answer many/most 4L60E questions here, I have limited experience with other people's transmissions and am certainly not a pro builder. I assume you have checked the obvious such as the fluid level and even tried overfilling by 1/2 quart.
I also always recommend connecting a pressure gauge to verify it is not too low or too high. The model "ATD 5550" is expensive and hopefully readily available in the UK. I suspect all trans shops and many auto shops have one.
Launching!
Joined: Feb 2004
Posts: 225
Likes: 3
From: Beavercreek, Ohio
I've experienced the same symptoms a time or two with my Performa Built 4L60E. This happened after I made some chassis improvements. Watching a video I noticed that my front end was much higher in the air at wot than it used to be. I overfilled my fluid by 1/2 qt. and the problem went away. Give that a shot next time you can test and tune.
Thread Starter
On The Tree
Joined: Feb 2003
Posts: 108
Likes: 0
From: MANCHESTER UK
Yes, the friction/steel combo becomes concave due to the thin/weak backing plate, especially with high line pressure.
When you back off, the trans shifts under less power letting the frictions grab and then hold the full power later. Think of your tires - once they spin you have no traction until you lift a bit and let them grab again.
Sonnax makes a updated input drum that holds one more friction, but more importantly has a very solid bolt-on backing plate that eliminates any chance of coning.
Also, you should have your line pressure checked. WOT should be around 225psi. Some builders think "more is better" and tweak the Pressure Control Solenoid to exceed that value which increases the chance of coning.
While I answer many/most 4L60E questions here, I have limited experience with other people's transmissions and am certainly not a pro builder. I assume you have checked the obvious such as the fluid level and even tried overfilling by 1/2 quart.
I also always recommend connecting a pressure gauge to verify it is not too low or too high. The model "ATD 5550" is expensive and hopefully readily available in the UK. I suspect all trans shops and many auto shops have one.
When you back off, the trans shifts under less power letting the frictions grab and then hold the full power later. Think of your tires - once they spin you have no traction until you lift a bit and let them grab again.
Sonnax makes a updated input drum that holds one more friction, but more importantly has a very solid bolt-on backing plate that eliminates any chance of coning.
Also, you should have your line pressure checked. WOT should be around 225psi. Some builders think "more is better" and tweak the Pressure Control Solenoid to exceed that value which increases the chance of coning.
While I answer many/most 4L60E questions here, I have limited experience with other people's transmissions and am certainly not a pro builder. I assume you have checked the obvious such as the fluid level and even tried overfilling by 1/2 quart.
I also always recommend connecting a pressure gauge to verify it is not too low or too high. The model "ATD 5550" is expensive and hopefully readily available in the UK. I suspect all trans shops and many auto shops have one.
I have the fluid set at correct level when levelish(car sits nose down).
Thinking about what Bird of Prey is saying makes sense, having watched a vid of mine since I fitted a solid rear anti roll bar the nose is still way up(see avatar) by the time 2-3 shift happens.
Before I bin it and fit a 4l80e I will try the overfill trick.
Thanks
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
As for tcs, the module on the shock tower that controls tcs limits wot. Meaning it only allows you to go like 95% throttle, maybe less. Deleting it would cause some change. Enough to cause your issue? Not sure but something to consider.
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Thread Starter
On The Tree
Joined: Feb 2003
Posts: 108
Likes: 0
From: MANCHESTER UK
I have just fitted a new TPS sensor, done re-learn, logged it and its reading 0-100% and the voltage is correct too.
Cheers
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Teching In
Joined: Dec 2005
Posts: 42
Likes: 1
I just fixed mine that was doing the 2-3 shift flare. My combo is in a ls swapped vehicle and the engine and trans is installed with eng/trans tilted down a little lower than stock at the rear to prevent cutting the trans tunnel. I slightly overfilled the trans and all issues went away.
I've experienced the same symptoms a time or two with my Performa Built 4L60E. This happened after I made some chassis improvements. Watching a video I noticed that my front end was much higher in the air at wot than it used to be. I overfilled my fluid by 1/2 qt. and the problem went away. Give that a shot next time you can test and tune.
I had a similar issue in my performabuilt. Upped my shift point from 6500 to 7K and it wouldn't go into 3rd under WOT. Pulled the trans to freshin it up and it had the Zpack. The friction material had started to flake off. Called performabuilt and they recommended the deep truck pan to help pump starvation. Replaced the 3/4 with BW HE 7 clutch setup and put a deep pan on and now I have crisp 2-3 shift at 7k.
Edit: The fluid looks fairly clean. Pulled the pan and it was super clean. Still was missing quite a bit of 3/4 material.