TC lock-up

[promisedland]

G'day folks! Question for you....
I have been trying to understand how my trans works,

= when i'm at heavy throttle and 3rd locks before 4th shifts, i have a pulse & then a jolt. I also have this if i'm at med+ throttle with OD off [my Ram this locks out OD=4th] and then i switch OD 'ON' and trans TC lock-up indicator light goes off, trans shifts, then wham!

I was wondering if the TC lock-up isnt completely disengaged when 4th shifts and then locks??? I have a Goerend triple disc TC, Trans Go shift kit, lock-up holes are PLUGGED, as i typed above, i added a wire to my trans so i know when my TC locks.
This is the only time TC lock-up hits hard, when this ^^^ happens it, feels like i was hit from behind...........

 

[Ozymandias]

No it doesn't disengage, just the solenoid flickers for a second, it is a locked-locked shift.

 

[Ozymandias]

It does the same if you shift manually from locked 2nd to 3rd.

 

[cerberusiam]

Typical triple disk problem with hard lockup. If you have not modified the VB to work with a triple and slow down the TCC apply you will get that when pressures and throttle are high.

Stock programming will not EVER allow a locked shift, only a pulsed lockup drop under certain conditions. However, the pulse width is not wide enough to allow a triple disk to unlock so you get rough shifts on pulsed lock\unlock. Another reason to use a single disk unless it is an absolute necessity.

 

[promisedland]

Hmmmm, more isnt always better. So, can VB be adjusted for this?
It feels like a locked shift.
Thanks.

 

[promisedland]

I just did the update for UDC Pro; maybe this will allow adjustment??
Didnt do any tuning yet, just downloaded it.

 

[cerberusiam]

Not the pulsed lockup on the shift, that is all computer controlled not mechanical. The hard lockup can be adjusted in the VB. Pro RT is going to have some 48RE tuning but not sure what it will be yet, that is still being finalized. I am hoping for pulse lockup control, lockup control, gov pressure tables, and TTVA adjustments. We shall see as the 48RE controls are rather crude.

 

[promisedland]

That ^^^ would be sweet! Thanks man.

 

[Ozymandias]

Stock programming will not EVER allow a locked shift, only a pulsed lockup drop under certain conditions. However, the pulse width is not wide enough to allow a triple disk to unlock so you get rough shifts on pulsed lock\unlock. Another reason to use a single disk unless it is an absolute necessity.

Like I said, the TC Light flickers for half a second, thats to short to really release hydraulic pressure out of the TC Circuit, so it is in real world a locked shift even if the solenoid opens for half a second.

 

[cerberusiam]

Like I said, the TC Light flickers for half a second, thats to short to really release hydraulic pressure out of the TC Circuit, so it is in real world a locked shift even if the solenoid opens for half a second.

Short answer, no. A pulsed pressure drop in the TCC circuit is enough to allow some slip in the clutch as the TQ rise happens. It does not fully release, that is correct, but it does release enough to buffer the TQ hit. If it did not it would snap the input shaft in short order.

It is worth repeating; Stock programming will NEVER allow a locked shift. However, this is based on a stock TC design and transmission build, ie pressures. Whose parameters are changed the results change, since the programming cannot be adjusted, yet, when selecting a TC and pressures one has to be aware of the potential results. Increase the apply pressures and fail to increase the release circuit size and the TCC is not going to release like stock. Increase the number of disks and the same thing happens. The triples are magnitudes worse as they just do not release fast enough to compensate. With a single disk you can somewhat alleviate it with pressure, but, with a good TCC it is a LOT firmer.

 

[p-Bar]

I just let off on the pedal a bit and it doesn't slam . I have a Goerend valve body with triple disc

 

[promisedland]

Well, i'm doin UDC-PRO by AH64ID,,,, So maybe we can tweak things a bit. I'll be your guinea-pig John! :-laf

 

[AH64ID]

We got a decent amount of control with UDC Pro; however, we did not get control over the pulse shifting.

 

[promisedland]

Well, some of us have triple disc TC's. How do you all deal with this?
HD input? Wire up a delay?

 

[cerberusiam]

We got a decent amount of control with UDC Pro; however, we did not get control over the pulse shifting.

I hope you kicked that back to Marco for future inclusion, and hopefully it can be added.

 

[promisedland]

I PM'ed Brian about it and will jab him to see how high he can jump...

Thanks Cerb.

 

[bigceltic]

Typical triple disk problem with hard lockup. If you have not modified the VB to work with a triple and slow down the TCC apply you will get that when pressures and throttle are high.

Stock programming will not EVER allow a locked shift, only a pulsed lockup drop under certain conditions. However, the pulse width is not wide enough to allow a triple disk to unlock so you get rough shifts on pulsed lock\unlock. Another reason to use a single disk unless it is an absolute necessity.

Cerb,

One clarifying question on the Triple Disc - assuming you get a pair - say a Goerend Triple Disc with a Goerend VB, can I assume that a Triple will not have this problem?

George

 

[cerberusiam]

Cerb,

One clarifying question on the Triple Disc - assuming you get a pair - say a Goerend Triple Disc with a Goerend VB, can I assume that a Triple will not have this problem?

George

Assume nothing. There are 2 instances when the TC locks, the normal part of the shifting algorithm that be controlled., and the pulsed unlock\lock on a 3-4 shift. The first can be controlled, the 2nd is a lot harder without electronics as the the unlock signal is just not long enough and ther eis really no way to modify that mechanically.

 

[bigceltic]

DISREGARD/Deleted. Re-read thread and Cerb had already answered this.

 

[cerberusiam]

So a good single TC does not have this issue, right?

To a point, that is true. Even with a single disk the lockup clutch surface is increased, apply pressures raised, and the efficacy of the lockup is increased. If you happen to work the throttle just right when the lockup occurs or the pulsed unlock on the 3-4 shift is in play it will bang pretty hard, bark the turbo, etc. It isn't the "rattle the dust off the headliner" lockup like you get with a triple but it can still be pretty hard. Best all around solution I have found is run it up to road speed in Drive then bring on OD when the TQ rise is much lower.