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TCC not locking up

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  #1  
Old 08-21-2023 | 06:27 PM
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Default TCC not locking up

Alright fellas, I have a 94 ram 1500 that I'm trying to put back on the road after sitting for 6 years, put a new engine in it a couple years ago and only drove it about 35 miles total since, anyway, issue is the Tcc isn't locking up, I know for sure the OD is engaging but I'm not getting lock up over 50mph, now I know pin 54 is the signal wire for the tcc, if I put a toggle switch on that circuit and ground that wire the converter will lock, problem is, I'd like to fix it right, yall think my PCM is bad? I've checked the wire from the pcm all the way to the trans and it's not broken, just isn't recieving signal from pcm, also there's no check engine codes.
 
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Old 08-22-2023 | 04:21 PM
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PCM supplies ground for the circuit, not power. If O/D is working, then you are getting power down to the trans. Are you getting a code for TCC lockup?

Usually, the trans will shift 1-2, 2-3, TCC, O/D. TCC is only a small drop in RPM. 200 or less, depending on your speed. Got a tach in your truck??
 
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Old 08-22-2023 | 06:40 PM
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Originally Posted by HeyYou
PCM supplies ground for the circuit, not power. If O/D is working, then you are getting power down to the trans. Are you getting a code for TCC lockup?

Usually, the trans will shift 1-2, 2-3, TCC, O/D. TCC is only a small drop in RPM. 200 or less, depending on your speed. Got a tach in your truck??
I do, you can feel it shift 1-2 2-3 and then what feels like another shift but then after that you don't get that extra drop, at around 55-60 it's turning around 2000 rpm. I used to be able to tap the brake pedal and you could feel it kick up that extra couple hundred rpm then if you weren't needing the power it would drop back down, it doesn't do that now, i can also push the O/D off button and it will turn the od off. but if I'm to run a toggle switch from a ground circuit, one end directly to ground and the other end to pin 54 and switch that at around 55-60 everything does as it should. No check engine lights, none that are lit up anyway.
 
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Old 08-23-2023 | 07:21 AM
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No check engine lights, none that are lit up anyway.
Does the engine light come on when you turn on the ignition? If not the bulb may be blown.
 
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Old 08-23-2023 | 07:35 AM
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Originally Posted by Moparite
Does the engine light come on when you turn on the ignition? If not the bulb may be blown.
Yes sir it does, i even checked the codes last night, all it had was 12, and i believe that one is because i had unplugged the pcm to check the terminals. I drove it again last night just so I could know and tell you guys how it shifts, it shifts 1-2 2-3 3-OD, at 45-50 she's running around 2000 rpm, if I push the OD off button the rpms raise by about 500 rpms depending on speed, at cruising speed if I just ease into the throttle without dropping a gear or gaining speed the rpms move about 3-500 as well, I know that the pcm isn't commanding the ground for the lockup i wired a light into ground circuit and drove it and it never lit up, but if I give it a ground myself like with a toggle switch it'll work everytime.
 
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Old 08-23-2023 | 10:13 AM
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What gears/tire size ya runnin'?
 
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Old 08-23-2023 | 12:06 PM
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Originally Posted by HeyYou
What gears/tire size ya runnin'?
3.55s with 315 75 16s, speedo is only 5mph off, checked that multiple times.
 
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Old 08-23-2023 | 03:56 PM
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35's on 3.55s????? Ouch. Your trans quite probably hates you.

Think I might install the switch in line (with an indicator light as well) that bypasses the PCM, just to see if manually locking it makes any difference. It's entirely possible the actual clutch is smoked.....
 
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Old 08-23-2023 | 05:36 PM
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Originally Posted by HeyYou
35's on 3.55s????? Ouch. Your trans quite probably hates you.

Think I might install the switch in line (with an indicator light as well) that bypasses the PCM, just to see if manually locking it makes any difference. It's entirely possible the actual clutch is smoked.....
Manually locking it with a switch works, I'd just like to maybe fix it like it's supposed to be. Lol
 
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Old 08-24-2023 | 07:26 AM
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Sounds like a pcm issue. Use the # off the old one to source a replacement.
 



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