Input about 2nd gear lock up at WOT

3

3rdgenmike

Member
What do y'all think of locking the converter at the top end of 2nd gear in a 48re at WOT? Trans is semi built with a stock sized billet input/output and tripple disc converter. Also has a transgo TFRE-PRO kit too. it has other small basic billet parts as well. Torque converter doesn't lock up hard, as i didn't drill the switch valve for harsher lockup . Trucks making 700-800hp. I have a stand alone controller controlling the trans and I'm just wondering if it's fine to be locking the converter at the top end of 2nd. It locks at about 3600rpm.
 
What kind of rpm drop are you seeing at the 1-2 shift? What's the shift rpm? I'd personally like it to lock up not long after the 1-2 shift, so it's not trying to lock then complete 2-3 shift too close together. Depending on how long it takes the trans to respond to commands from the controller
 
what the point of lockup at redline..all the wasted energy due to any slippage is already done....or is this some 45oo rpm truck asking about lockup questions
 
I have my 47re set to lockup 3 or 4 mph after the 2nd gear shift at wot on my anteater. Never had any issues with georends converter and standard size billet input and it locks up pretty firm.But my truck only made 624/1240. I should mention I have a decent shift bind on the 2-3,i figured a locked wot 2-3 shift would've snapped my intermediate by now but somehow it's still alive. Going on 5 years now
 
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Snedge said:
100 HP give or take, I found that funny. LOL

Like it's not that big of a difference.
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I haven't put the truck on a dyno, so I gave a wide range. S467.7 with flux 150hp sticks and dual cp3s. On paper it should be closer to 800, but I rather not say something it isn't.
 
JWhite said:
What kind of rpm drop are you seeing at the 1-2 shift? What's the shift rpm? I'd personally like it to lock up not long after the 1-2 shift, so it's not trying to lock then complete 2-3 shift too close together. Depending on how long it takes the trans to respond to commands from the controller
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When it locks, it's a pretty decent drop, almost 1k drop in rpm. I have the shifts decently spaced apart so it doesn't shift too quickly. 3rd gear is about 68mph and 4th is 86mph
 
dieselbeef said:
what the point of lockup at redline..all the wasted energy due to any slippage is already done....or is this some 45oo rpm truck asking about lockup questions
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I only spin it to 4k, not 4500. Truck can spin to 5k, but I'm too much of a chicken to go that high. But yeah, basically a 4500 rpm truck asking lockup questions lol.
 
thatguy69 said:
I have my 47re set to lockup 3 or 4 mph after the 2nd gear shift at wot on my anteater. Never had any issues with georends converter and standard size billet input and it locks up pretty firm.But my truck only made 624/1240. I should mention I have a decent shift bind on the 2-3,i figured a locked wot 2-3 shift would've snapped my intermediate by now but somehow it's still alive. Going on 5 years now
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5 years? I might be okay then lol.
 
Can you video the dash on an acceleration run? I'de like to see how much time this is taking to get through the gears.

Thread derail.... how do you like the TFRE-PRO?
 
56cummins said:
Can you video the dash on an acceleration run? I'de like to see how much time this is taking to get through the gears.

Thread derail.... how do you like the TFRE-PRO?
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I can yeah, won't be till later tonight though.

I like it. It seems to hold the power for now. Haven't had any issues thankfully. 3rd gear is the only thing that's a little bothersome. When it goes into 3rd at low speeds, feels like you hit a dip in the road. It jerks you forward pretty good. Under some decent throttle it doesn't do it and it can be a pain while towing. Talked to transgo and they said it's supposed to happen and I'm not the only one that isn't a fan of it lol.
 
IMO if you're not going to lock the converter as soon as 2nd gear hits, there's no reason to even subject the trans to a locked 2-3 shift at that RPM.

As someone who has broken a shitload of billet intermediates and input shafts on a locked 2-3 shift, would recommend ditching that VB ASAP if you have even the slightest concern.
 
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3rdgenmike said:
I can yeah, won't be till later tonight though.

I like it. It seems to hold the power for now. Haven't had any issues thankfully. 3rd gear is the only thing that's a little bothersome. When it goes into 3rd at low speeds, feels like you hit a dip in the road. It jerks you forward pretty good. Under some decent throttle it doesn't do it and it can be a pain while towing. Talked to transgo and they said it's supposed to happen and I'm not the only one that isn't a fan of it lol.
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Sounds like a bad shift bindup on your 2-3
 
RascalMafia said:
IMO if you're not going to lock the converter as soon as 2nd gear hits, there's no reason to even subject the trans to a locked 2-3 shift at that RPM.

As someone who has broken a shitload of billet intermediates and input shafts on a locked 2-3 shift, would recommend ditching that VB ASAP if you have even the slightest concern.
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Yeah, I've been messing around with 1-2 2-3 3 locked and then 3 locked to 4 recently. Probably going to stick with that.
 
thatguy69 said:
Sounds like a bad shift bindup on your 2-3
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I'm not sure to be honest. Transgo said it was fine and I've heard other people complain about it to. I might be explaining it bad, but it does do it no matter where I adjust the 2nd gear band. If I leave it at factory specs (I think after torque it's turn out 3 turns?) Or to transgo specs (1 and 1/4 out?), it still does it.
 
3rdgenmike said:
I'm not sure to be honest. Transgo said it was fine and I've heard other people complain about it to. I might be explaining it bad, but it does do it no matter where I adjust the 2nd gear band. If I leave it at factory specs (I think after torque it's turn out 3 turns?) Or to transgo specs (1 and 1/4 out?), it still does it.
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Well it's not supposed to happen. Your 2nd gear servo/lever ratio/direct clutch clearance/vb setup all have to align to get a nice clean 2-3 shift.
 
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