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Re: 4l60e 2-3 slipping shift
Posted: Mon Sep 23, 2024 7:12 pm
by Wade
Just a thought. Could try retarding ignition timing up around redline or right where it’s shifting to reduce torque which might help.
Re: 4l60e 2-3 slipping shift
Posted: Mon Sep 23, 2024 8:15 pm
by immortality
Just having a look at the data log. Force motor current stays constant through the 2-3 gear change so line pressure should be at maximum (with no transient modifications).
Have you tried manually shifting 2-3 and seeing if it behaves the same?
Re: 4l60e 2-3 slipping shift
Posted: Mon Sep 23, 2024 8:30 pm
by immortality
Also, looking at the rate of acceleration Vs engine RPM it looks like trans slip increases as the rate of RPM increase goes up but there isn't a corresponding increase in rate for road speed.
Re: 4l60e 2-3 slipping shift
Posted: Mon Sep 23, 2024 9:15 pm
by vp304
Deuce wrote: ↑Mon Sep 23, 2024 7:07 pm
delcowizzid wrote: ↑Mon Sep 23, 2024 5:38 pm
Once you start making enough torque they start to slow change on the 2-3 and will quite often smack the limiter a couple times before shifting even the t700r4 with a full manual shift kit does it at around 10-12psi of boost
Yeah, that sounds like mine.
1-2 from commanded shift until minimum rpm point in 2nd (start of accel in that gear) approx 1sec.
2-3 from commanded shift until minimum rpm point in 3rd, approx 2.5seconds.
Lazy!!
My vr 4l60e does exactly the same as this tho i havnt had enough time to log it to see whats going on tune wise
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 2:09 am
by Wade
Yeah looks like it’s slipping all the way through 3rd
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 6:21 am
by vscapricetim
So manually shift shifter 1 2 3 under wot? Does that then use the manual tables?
I did notice in a log yesterday that it's telling me cruise control is active.... don't know how that's possible as its not connected....
Ill post a log of a worse shift than that one.
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 8:43 am
by immortality
Wade wrote: ↑Tue Sep 24, 2024 2:09 am
Yeah looks like it’s slipping all the way through 3rd
Yes, it doesn't look like 3rd actually fully engages.
vscapricetim wrote: ↑Tue Sep 24, 2024 6:21 am
So manually shift shifter 1 2 3 under wot? Does that then use the manual tables?
I did notice in a log yesterday that it's telling me cruise control is active.... don't know how that's possible as its not connected....
Ill post a log of a worse shift than that one.
On this one it looks like it starts to pull down the RPM going into 3rd but then flares again.
What fluid did your transmission builder recommend? Do you know what when into the build?
Dex 6 is slipperier than DEX III. Dex6 is also slightly thinner than Dex III. I know the manufacturers say it is backwards compatible but I disagree.
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 11:14 am
by vscapricetim
I bought it 2nd hand from a forum member here and he said to run dex6. That's what he was using.
Box is fitted with beast shell billet sungear upgraded servo modified valve body extra clutches and 5 pinion planetary is what he listed. I'll see if he has the build list.
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 11:57 am
by immortality
I'd try changing to Dex III first.
Re: 4l60e 2-3 slipping shift
Posted: Tue Sep 24, 2024 2:34 pm
by vscapricetim
Will do, ya need to flush dex 6 out completely or is ok to mix and match? I have a drain plug so it'd make it alot easier.