Torque Converter lockup issues using lockup switch.

Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
I'm having some issues with my converter locking up while sled pulling. I have a dhd lockup switch. Converter will lockup right away as long as I'm turning under 3250 rpm. Any rpm about it it won't lock up. Any ideas before I pull my tranny.

Truck has a full built engine s400 charger making mid 700 to 800 rwhp. I use a 3rd gear start tcm tune, tow haul enguaged. Truck has a suncoast gmax 6-3 kit with 1056 converter. Mike L pump spring, transgo converter valve and transgo shift kit.

Truck also did this least year while running a stock appearing danville 2.5 charger.
 

CaptPhil

Active member
Sep 10, 2011
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Delaware
Interesting. Mine never had any problems locking over that rpm. Have you tried running the rpm up without being wot and seeing if it will lock?

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Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
I'll have to try that. I beleive I have tired it before but can't guarantee I wasn't wide open. Only time I ever use it is sled pulling. I'll need to take it out and play with it on an open road some night this week.
 

mike diesel

I'm alright.
Sep 6, 2012
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SLC, Utah
Does it seem like it fully unlocks or does it seem like it's slipping?

Is your pump spring shimmed? If it isn't shimmed, in conjunction with the transgo converter valve, you are dropping line pressure when the converter locks, down to around 250psi, which isn't going to hold 800hp well at all.
 

Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
It does fully unlock. And when it locks it seems to be fully locked. I don't have any shims in yet. But that's in main plans when it comes out soon. Aldo going to replace the tc solonoid and looking in to the tc lockup valve mod for 0 pressure drop. Going to add mike L 's trim springs also.
 

Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
I was gonna get a suncoast 1053-1 3d but the full billet stator quad disk dpc us a little cheaper and a quad disk. What are you guys recommending. Truck is pretty much just a trailer queen now gonna be a strict puller soon. So I'm not worried about drivability anymore. I'm taking it to mark here this Thursday for dyno tuning with the new 2.5 charger he's building for me this year.
 

IOWA LLY

Yes, its really me
Feb 23, 2007
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For that application I would go Georend. Period.

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Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
Thanks Evan, I was Gonna to try and get a hold of you to see if you had any ideas why my torque won't lockup over 3250 rpm. Here in a few weeks I'll call you and get one from you then..
 

Evan@InglewoodTrans

yerp
Vendor/Sponsor
Aug 5, 2010
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Western MA
Did you try a Georend?

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Of course. There is nothing wrong with Georend converters at all it's just when trying to get Mike Graves truck to stay together he made fairly quick work of everything but the 10531. We haven't needed the converter gone through and it's been a few years. The same one is going right back in this year. Mike isn't shy about making passes and they are almost always in low 10's
 
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