How to correct a hard TC lock up.

[Mhennessy]

Gents,
2004.5 48re.
I have a built trans (billet input and upgraded VB) The exact details are unknown as it was done prior to me owing it and the builder just rattled off what he usually puts in them.
Anyway the TC lock up towing is really hard!! I do have a triple disk and she is fine when normal driving but when towing moderate to heavy this thing feels like its going to tear a shaft when it shifts.
Is there something I can do to correct it? I heard tale that I could pull the VB and plug a few holes that may have been added to help smooth it out.
I am pretty mechanically inclined but depending on the work may sub this one out to a builder.
Thanks for the help.

 

[AdamRRT]

Unless you have a lockup "mystery switch" on it, there's no reason that it should be shifting while locked up.
So is it while shifting or when it locks up? Just for clarification.

 

[AEdelheit]

A lot of what you are feeling is likely axle wrap when it shifts, a good set of traction bars such as Patton Fab that are the correct geometry for the leaf springs really smooths out the shift.

Aside from that if the valve body and TC are not properly matched it can be very difficult to smooth out.

 

[Mhennessy]

Unless you have a lockup "mystery switch" on it, there's no reason that it should be shifting while locked up.
So is it while shifting or when it locks up? Just for clarification.

It does not shift while locked up. All the gear shifts are fine but the lock up is hard as hell.
I do have the mystery switch but it is only used on down hill grades or low speed hill towing where I hold it in gear.

 

[Mhennessy]

A lot of what you are feeling is likely axle wrap when it shifts, a good set of traction bars such as Patton Fab that are the correct geometry for the leaf springs really smooths out the shift.

Aside from that if the valve body and TC are not properly matched it can be very difficult to smooth out.

I did not even consider axle wrap but now that you suggest it i am sure that is also happening as it sorta feels like everything "bounces" around under there when she locks up hard. I think that is some that also needs addressed.
Thanks you.

 

[promisedland]

I have a shift kit with the triple disc georend TC.
I had hard lock up but when I had the holes plugged that were drilled for the stock TC, this fixed my prob.
EXCEPT when my trans locks up on 3rd when the pedal is close to the floor, then when she goes to unlock & shift to 4th, the big TC dosnt unlock fast enough & bam! I'm not sure how to fix it.
Maybe a valve body?

 

[Mhennessy]

I have a shift kit with the triple disc georend TC.
I had hard lock up but when I had the holes plugged that were drilled for the stock TC, this fixed my prob.
EXCEPT when my trans locks up on 3rd when the pedal is close to the floor, then when she goes to unlock & shift to 4th, the big TC dosnt unlock fast enough & bam! I'm not sure how to fix it.
Maybe a valve body?

I actually heard this from another source that if I plugged a few holes in the VB that would smooth out the lock up. I just need to find out if this is something I can tackle or if I need to bite the bullet and have a trans shop do it.
Thanks for the input.

 

[Ozymandias]

I'd recommend to ask the seller/builder of the valve body about that topic and what to do to tackle that issue.
If you mess up your transmission is likely toast.

 

[Killer223]

lockup speed and firmness is all in the valve body.
@Dynamic transmissions is who i'd talk with.
i had Fred Swanson build mine and it's been absolutely amazing. but i believe he retired.
in the mean time you can let off the gas a little just before the lockup happens and it should help it not be so harsh.
if slowing down give it a little fuel almost like floating the gears and it'll lockup softer then let off the gas totally.
that's what i had to do with mine for a while.

 

[Darkbloodmon]

I'd recommend to ask the seller/builder of the valve body about that topic and what to do to tackle that issue.
If you mess up your transmission is likely toast.

My vote is go too the Horse's mouth. They built it. There nothing more frustrating than trying to figure out someone else's work to solve a problem you have.

 

[promisedland]

As above, try to find out what's in it, Dynamic knows his stuff.

Just to clarify, I did the trans-go shift kit with stock TC and this was good, holes where drilled to speed up lockup.
Added a triple disc TC and every lockup was harsh.
Plugged the holes and it's great, except for the 3-4 locked shift as I described above. I think it's valve body but I'm done spending

 

[Ozymandias]

As above, try to find out what's in it, Dynamic knows his stuff.

Just to clarify, I did the trans-go shift kit with stock TC and this was good, holes where drilled to speed up lockup.
Added a triple disc TC and every lockup was harsh.
Plugged the holes and it's great, except for the 3-4 locked shift as I described above. I think it's valve body but I'm done spending

Check that little steel plate on top of the VB, this hole in it is drilled bigger for firmer lockup from what i know.
You might want to change it back to OEM.