No 2-3 shift at WOT ***SOLVED***
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From: So.Cal.
What RPM's in 2nd gear and 3rd gear do those WOT shift point MPH's correspond to...?
RPM = MPH * 336 * GR / TD
where:
GR = trans ratio * axle ratio
TD = tire diameter (inches)
RPM = MPH * 336 * GR / TD
where:
GR = trans ratio * axle ratio
TD = tire diameter (inches)
Last edited by joecar; Jun 15, 2017 at 09:15 PM. Reason: fixed strange characters from my phone
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From: So.Cal.
Make WOT upshift MPH achieveable (i.e. RPM can be achieved without hitting limiter).
Make WOT downshift MPH at least 5 MPH lower than the upshift.
Are you seeing any DTC's...?
Make WOT downshift MPH at least 5 MPH lower than the upshift.
Are you seeing any DTC's...?
Last edited by joecar; Sep 3, 2019 at 12:26 AM.
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From: Laurel, MS
Thread Starter
Teching In
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From: Laurel, MS
TECH Senior Member
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From: So.Cal.
TECH Senior Member
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From: So.Cal.
RPM = 42.97 * 336 * 4.63 * 1.625 / 34.7 = 3130 rpm
you can raise the 2->3 WOT upshift higher;
and also lower the 3->2 downshift a little
( the downshift must be below the upshift )
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From: Laurel, MS
I also bumped the upshift rpm back up to 5200 because when it DOES shift ( during passing) it happens too soon.
Then I got out on the interstate and nailed it. 1-2, great. 2-3 went to the rev limiter again.
I keep thinking that second isn't releasing, which prevents third from engaging. Maybe when the new band wears a bit, it will magically start working properly.
Any thoughts on the low-ish pressure?
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From: So.Cal.
I keep thinking that second isn't releasing, which prevents third from engaging. Maybe when the new band wears a bit, it will magically start working properly.
Any thoughts on the low-ish pressure?
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From: Laurel, MS
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From: So.Cal.
If pressure is low, this indicates that the pressure regulator is worn (the valve wears the bore), this also means the trans slips, this is one of the causes for missed WOT upshift.
What does pressure gauge show when idling in R, N, D...?
What does it show at WOT...?
What does pressure gauge show when idling in R, N, D...?
What does it show at WOT...?
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From: Ann Arbor, MI
I'm curious what the line pressure is during the 2->3 shift.
Running only 50 psi is Reverse is strange - the reverse circuit moves the boost valve into a higher pressure position. Makes me wonder if the boost valve is sticking or has a significant leak. I suggest installing the Sonnax 4L60E-LB1 (or LB2 for 2006+) into every rebuild or even stock unit. It increases line pressure across the board and it;s o-rings prevent leaks.
A sticking valve in the VB could be the culprit but i don't recall a single thread where that was the cause.
Running only 50 psi is Reverse is strange - the reverse circuit moves the boost valve into a higher pressure position. Makes me wonder if the boost valve is sticking or has a significant leak. I suggest installing the Sonnax 4L60E-LB1 (or LB2 for 2006+) into every rebuild or even stock unit. It increases line pressure across the board and it;s o-rings prevent leaks.
A sticking valve in the VB could be the culprit but i don't recall a single thread where that was the cause.
Thread Starter
Teching In
Joined: May 2017
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From: Laurel, MS
I'm curious what the line pressure is during the 2->3 shift.
Running only 50 psi is Reverse is strange - the reverse circuit moves the boost valve into a higher pressure position. Makes me wonder if the boost valve is sticking or has a significant leak. I suggest installing the Sonnax 4L60E-LB1 (or LB2 for 2006+) into every rebuild or even stock unit. It increases line pressure across the board and it;s o-rings prevent leaks.
A sticking valve in the VB could be the culprit but i don't recall a single thread where that was the cause.
Running only 50 psi is Reverse is strange - the reverse circuit moves the boost valve into a higher pressure position. Makes me wonder if the boost valve is sticking or has a significant leak. I suggest installing the Sonnax 4L60E-LB1 (or LB2 for 2006+) into every rebuild or even stock unit. It increases line pressure across the board and it;s o-rings prevent leaks.
A sticking valve in the VB could be the culprit but i don't recall a single thread where that was the cause.
I'm not opposed to replacing it with the sonnax part.
I'll order one. I have a feeling I'll be pulling the pan soon to poke around. Might as well at least do something that "can't hurt".
@joecar. When it should be shifting, the pressure is high. Like around 200. But as soon as I get the ac back together, I'll go for a drive and see exactly what it is reading at that moment.
Now, if this rain will just let up...
Last edited by Reserector; Jun 17, 2017 at 07:28 AM.
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From: Laurel, MS
Boost valve is ordered.
Another thing I've noticed, that might be pressure related, is a slight pulsing around 35 when I'm just poking along, and it's locking up the converter. It never did that before the rebuild, and it doesn't set a code.
Wondering if I should pull the VB and update the TCC valve while I'm in there. I'm open to suggestions. It just seems strange that it only started this after the rebuild.
when it is pulsing, pressure is around 100-125. It only varies about 5 psi, and is not jerky.
Another thing I've noticed, that might be pressure related, is a slight pulsing around 35 when I'm just poking along, and it's locking up the converter. It never did that before the rebuild, and it doesn't set a code.
Wondering if I should pull the VB and update the TCC valve while I'm in there. I'm open to suggestions. It just seems strange that it only started this after the rebuild.
when it is pulsing, pressure is around 100-125. It only varies about 5 psi, and is not jerky.
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From: Laurel, MS
At wot, it's at 160, but just after a shift, it jumps up to 220 for a moment.
Interestingly, when it failed to do the wot 2-3, it still jumped up to 220 as of it had.
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From: Laurel, MS
Bypassing somewhere? Boost valve is my guess.
I know for a fact that it has the pump screen and it's o-ring that is sometimes left out, causing a bypass. It's not that.
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From: Ann Arbor, MI
Engine upgrades should be combined with transmission upgrades such as a shift kit or even overhaul if the miles are high.
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From: So.Cal.
