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#1
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TH400 late shifting when manually shifting gears. (Under full throttle)
Sometimes, I like to shift my wagon manually when I do "spirited" driving. An issue I have noticed when I do this, is that there is a delay of a few seconds when I upshift under full throttle. I think it must be the nature of the beast. if there is an "issue" any ideas?? Governor? Modulator? I would prefer it to shift right away if possible when I do this. I have noticed this exact same situation with the TH350 in my other car. Both cars have the Trans Go reprogramming kit. The TH400 in the '66 Tempest Custom has the 4L80e sprag upgrade, as well. I am curious if any of you have done anything to remedy this "issue"? Both transmissions will shift right away if I manually shift at low or medium rpm, and both downshift right away too. But I usually just let it shift for itself anyways in normal driving.
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#2
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What RPM do those shifts happen at when it shifts automatically?
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#3
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About 5200. It is a '73 455, with forged rods and forged pistons.
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#4
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It seems like it shifts even higher when I put it into second from first if shifting manually. It starts to float the valves. I installed another governor today (the other one was modified) and the shifts in drive seem to be spread out a lot better, and the downshifts are even better. It still will delay, and shift at higher rpm if you do it manually. Granted, this isn't a real "problem" as I can just let it shift by itself in drive. I also have a Gear Vendors unit in the car. Just curious why it does this. I mistakingly "assumed" that with the Trans Go kit, it would shift up and down whenever I moved the shifter, without governor override.
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#5
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Check your checkballs
and that pesky 2-3 accum Puck in the VB needs flipped while you are in there. |
#6
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I have no idea how my th400 has been prepped, but my manual shifts, both 1-2 and 2-3 happen basically instantly as soon as I bump the shifter. The previous owner mentioned having work done to the trans, so I don't know if this is typical of stock th400 behavior or not. But it does show you can get those instant shifts out of the trans if that's what you're after.
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-Jason 1969 Pontiac Firebird |
#7
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I just love the instant TH400 up & down shifts.
However my 4L80 doesn't hold ANY downshift gear; the OD Sprag allows freewhellin and i have not investigated it. No engine braking, but also i dont have to give it gas anymore when going downhill.
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12.24/111.6MPH/1.76 60'/28"/3.54:1/SP-TH400/469 R96A/236-244-112LC/1050&TorkerI//3850Lbs//15MPG/89oct Sold 2003: 12.00/112MPH/1.61 60'/26"x3.31:1/10"/469 #48/245-255-110LSA/Q-Jet-Torker/3650Lbs//18MPG 94oct Sold 1994: 11.00/123MPH/1.50 60'/29.5"x4.10:1/10"/469 #48/245-255-110LSA/Dual600s-Wenzler/3250Lbs//94oct |
#8
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Shift
My 71 GTO has a TH400 with a shift kit. I believe it may be a B&M kit but not sure. The automatic wot shift was set at about 4200 rpm. When I manually shift wot above that rpm it would shift instantly as soon as I move the shifter. I played with the governor a while back and moved the wot automatic shift point up to 5000 RPM. Now when I manually shift it wot below 5000 rpm there is a delay before it shifts. If I don't get on it full throttle I can get instant manual shifts at any rpm but have to get it just right.
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'71 GTO, 406 CID, 60916, 1.65 HS, '69 #46 Heads 230CFM, 800CFM Q-jet, TH400, 12 Bolt 3.55 '72 Lemans, Lucerne Blue, WU2, T41, L78, M22, G80 |
#9
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