Lock up valve ?

[Lee Thompson]

The 3rd land down from the springs has 2 flats ground on it 180 degrees apart (lock up spool). Why ? Is this good or bad ? Necessery or a waste of time ? Thanks

 

[WE4]

Never seen that. You sure it's not the PR valve? Lock up valve should have no flats.

Bruce
We4

 

[Lee Thompson]

Lock up valve

Yes it is the L/U valve. A friend of mine ordered this trans from TCI, also ordered a convertor.
Looks to be a 12 in. convertor. (lock up). We were wondering what was the purpose of grinding the flats. Thanks

 

[blackplague]

To increase cooler flow

This mod is to increase cooler flow when the converter is locked up. It can be done a few ways, by the flats you have on the valve now, i usually chuck them up in lathe and take .010 off the land.

 

[MeanBuicks]

Yep. Under normal operation the lube circuit is forced through a very small orifice in the pump once lock-up is applied. By putting a couple flats on that spool, lube flow doesn't decrease when the trans. goes into lock-up. It follows a similar path as the non-locked operation.

 

[WE4]

Somethings amiss here guys. Greg, I believe you are not correct. Cooler circuit is open and flows more when locked. Unlocked is where the restriction is. Thats why you should lock a lock-up.
Cooler flow is less unlocked. Now if they are grinding the second land it might increase under no lock but once valve strokes for LU it all going thru cooler.

Bruce
WE4
www.ptsnctb.com

 

[blackplague]

This is just an opinion

This is just an opinion.

The out to cooler circuit has two lines that feed it. one has the orificed cup plug and the other is wide open. When the valve is unlocked { valve towards solenoid } the apply\return line from the converter is feeding both circuits. When the valve locks, {valve away from the solenoid} the third land {counting from either end of the valve} blocks off the open end of the to cooler circuit and forces the lube oil thur the orifice only. Grinding the third land on the lock up valve lets oil from converter feed to the open cooler circuit. {in theory}

That's weird though how when you unplug the harness and leave it hang, the trans burns up quick. {HUMMMMMMM}

 

[MeanBuicks]

Re: This is just an opinion

Originally posted by blackplague
The out to cooler circuit has two lines that feed it. one has the orificed cup plug and the other is wide open. When the valve is unlocked { valve towards solenoid } the apply\return line from the converter is feeding both circuits. When the valve locks, {valve away from the solenoid} the third land {counting from either end of the valve} blocks off the open end of the to cooler circuit and forces the lube oil thur the orifice only. Grinding the third land on the lock up valve lets oil from converter feed to the open cooler circuit. {in theory}

Well, in theory and in real life. Actually, you explained it properly. The increase in cooler flow/lube can be seen on our test machines quite clearly when lock-up is activated with the ground valve. Fluid is allowed to flow through both the orifice and the open passage.

That's weird though how when you unplug the harness and leave it hang, the trans burns up quick. {HUMMMMMMM}

That's more a function of the converter pushing/slipping against an overdriven input shaft. Without other enhancements to the cooler/lube system, it'll tend to get hot.