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Discussion Starter #1
Good afternoon. I’m converting my 01 Silverado 2500HD, from a 4L80E auto to a NV4500. I’m and electrician that love to tinkle with non electrical stuff when I’m off. Can someone who did this swap of know of someone that did the swap, help me with a few things please. I already have the clutch pedal and master cylinder installed. The 4L80E removes. The auto tranny went bad and I honestly prefer manual to auto
Questions:
1. Will I have to change my computer?
2. How will the reverse light work?
3. Is there an adapter of some kind, that will support the wiring from the auto tranny.
I’m sure there a lot more to this and I will appreciate any advice, comments and tips offered.
 

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‘01 Silverado 2500HD 8.1/Allison 5sp xcab long bed
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The 4L80E Is completely computer controlled. The computer will be looking for feedback from the computer constantly and will throw trouble codes the moment you start it up.

Some measure of programming will be necessary to turn off the shifting logic. The reverse light and neutral safety logic will have to be wired in. The reverse switch is in the 4500 case. The neutral start and cruise override switches will have to be cut in.
 

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Discussion Starter #3
Cowboytrukr:
Thank you for the information. I really appreciate it.
would you happen to have a link to where I can go to see how to do that?
 

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There’s really not one that I’m aware of. Could be, I just haven’t searched for one. I know about the auto vs manual thing because I have a manual trans truck and had to temporarily use a computer chip from an auto truck when I built my new engine just to get it to fire and get it timed, I just grabbed any 5.7 chip I could find. Turned out to be an automatic. About 2 dozen trouble codes came as soon as I fired it up. Once I got it running well I had to hunt down a computer from a ‘94 to make the codes go away. That was a wiring challenge.

I’m not even sure how you would go about programming the computer. I’m certain there are some great shops that can do it for you. There are some skilled tuner guys on here that will be along to provide better guidance.

As for the reverse, neutral start and cruise disable, those I can help you with. You will need to get your hands on a wiring diagram for the transmission so you can locate the reverse lamp circuit.

For the cruise disable and neutral start, you will need to get yourself a couple of these switches.

063BA170-9D80-4924-83E5-CFAA8B225FBE.png


the brake pedal lever should have a switch attached somewhere. If they held to earlier standards, it should have three contacts. One for the brake lights, one for the torque converter lockout, and one for cruise disable. The wiring diagram should help to find which wire is the cruise circuit. Take that one and wire in series one of these switches. It should rest against the clutch pedal lever when the clutch is fully engaged.

The second switch goes back against the firewall for the start engage. This one needs to be in series with the downstream lead from the AT park/neutral circuit. The new switch should be set far enough back such that you will need to be at full travel to ensure that the clutch is fully disengaged.
 

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The reality TV Hot Rodding and Customizing shows often do this sort of work. The computer reprogramming is usually taken to Dyno Testing shops and or motor rebuilding specialists. If you can find any businesses along those lines in your area they might be able to get you going. Your electrical skills are valuable to those business. A little bartering might make a lot of people happy.
 

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Discussion Starter #7
Thank you for that information, I however live on a small island in the Bahamas, finding that type of shop isn’t an option. I will have to take it to florida on my next trip.
 

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You risk over speeding the engine when you shift. Downshifting will not disengage the throttle.

Now, if you’re the only ever driving this, just remember to tap the brake before downshifting. If it were me, I’d forget to do that and panic when the cruise tries to maintain speed and run it to 4000 rpm.
 

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Discussion Starter #10
Noted with thanks, I will try to figure out which of the 6 wires, that go to the break pedal is for the cruise, I will forget to press the break. I also noticed there’s a start relay circuit that run thru the safety switch, that need to be connected.
 

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Yes, the start relay needs to include the switch that goes against the firewall.
 

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Discussion Starter #12
Good morning I have two more questions, please.

1. Can someone help me to identity the cruise circuit from the attached photo please, I know the orange and white wires are the brake lights.
2. Can someone help me to figure out if my NV4500 is GM or Dodge?
 

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Discussion Starter #14
i See the the cruise on the break pedal is normally closed, and pressing the break opens it, can I just take out the fuse for the cruise control, to disable it?
 

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Yes
 

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Discussion Starter #17
Good day, I just found an old GMC Sierra Grande 35, can anyone tell me it the 4 speed gear box from that, would bolt up to a 95 to 01 Silverado?
 

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We need engine info from both; but the answer is probably yes
 

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Good day, I just found an old GMC Sierra Grande 35, can anyone tell me it the 4 speed gear box from that, would bolt up to a 95 to 01 Silverado?
You are aware that there are two engine changes over that range you’re asking about, right? 1995 was the last year of the TBI. 1996-mid 1999 ish, was the Vortec era, and the 4.8/5.3/6.0 came after.
 
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