1936 LS1

iTrader: (10)

About to tackle the wiring and realized my trans doesn't have one. Is it required in a transplant?

46Coupe

iTrader: (5)

From what I read, it is used by the computer to kick the idle up a little bit when it is in gear.

As far as being required, I don't think it is.

1936 LS1

iTrader: (10)

Thanks, 46Coupe.

Anyone else actually done away with it? I'll buy one if it'll simplify things, but if it can /should be programmed out, I'll delete it and the wires for it.

STEEPSS

iTrader: (30)

I'm sure you'll be fine without one. Plenty of guys running the streets with th350 / th400's without em.

Pocket

iTrader: (22)

Column shifted auto trans had them. Any LSx auto with a floor shifter didnt. In a nut shell, your PCM needs to know when you're in park/neutral vs any gear/reverse. If you stock shifter has this covered you can delete the range switch

1936 LS1

iTrader: (10)

Pocket, thanks for the reply but your statement seems to contradict itself. If the PCM "needs" to know what gear you're in, how does it get that info in a car with a floor mounted shifter?

F-Body cars don't have this?

I don't have a "stock" shifter in the '36. I currently have a column from a '70s Nova (I think) with a column shift. Haven't decided for certain what my final configuration will be (floor vs. column).

Thanks for the reply, I don't mean to be so dense!

G-Body

iTrader: (4)

It can be changed/deleted as needed. What year PCM are you running and what kind of trans? If its a red/blue PCM and non electronic trans I would switch it over to a P/N switch when you have the PCM reflashed and hook up a P/N switch to your shifter. Same basic idea if its a blue/green PCM. If you are running an electronic trans I would keep the PRNDL switch, you can actually run without it but it would have to be programmed out of the PCM and the car will have better driveability with it. IE: It will kick the idle up a bit when in drive, there are different spark and airflow tables for drive and park, etc.

1936 LS1

iTrader: (10)

G-Body,

That's exactly the info I was looking for. I'll add one. It's less work than deleting it and it does have some benefits. Thanks.

BTW, It's an '04 Truck Transmission and an '05 Truck Harness and PCM behind an '02 5.3.

Pocket

iTrader: (22)

The PCM need to know when the trans is in gear vs in P/neutral. Beyond that it couldnt care less

Since you're using a column shifter, leave the switch in place. The P/neutral function and back-up lights are the only useful wires

ModMuscle

What switch are you guys talking about? Any pics? I am finishing up an LS2/4L70 install and am having some issues with idle speed and gear selection. Basically, in park and neutral, it idles perfectly normal. When I put it in Reverse or Drive, the rpms go up and you have to have your foot on the brake good but then it comes back down to normal after 5 seconds or so. It only does it when switching into one of those two. Going to park doesn't do it...going to Neutral doesn't do it. In fact, switching out of reverse or drive while the rpms are up will make them come back down. I'm trying to figure out if its a mechanical problem with my transmission or if it is a tuning issue. Also, the timing of the shifts feels off too.

Sorry to hijack the thread. Just interested in what this switch is and if it may be my problem?

Thanks

rfrankb4

Could you please clarify what you mean when you say that the PCM needs to have that information. What does it control? Is it just the slight increase in idle?

I have a 2007 express van with a 2006 express tune, cable TB and 4l80e with 3200 stall. I hope to start it for the first time next week. A slight increase in idle overall should not be a big issue with the increased stall as far as i can see. However, if it will cause other issues or cause issues I have not heard of yet I can add these wires back in to my harness.

I am also using a F body shifter so I could wire to that if the computer will support it and I can find out if i need to supply a ground or a hot and to witch pin.

Pocket

iTrader: (22)

Essentially, yes

Fbody floor shifter you can delete the trans switch or simply leave it unplugged. Fbody shifter: PCM P/neutral pin ORN/BLK to shifter connector pin B. Shifter connector pin A BLK/WHT to GRD

Other wires on the shifter are for back-up lights and starter safety switch

rfrankb4

Thank you for the thoughtful answer.

ModMuscle

Hey guys...I had my car at the tuner on Thursday. I was getting a pending P0705 transmission range code. I asked him if we could tune it out. He went in and where it shows the codes for him to work with...that code wasnt there. There was nothing he could do with it. He was using HP tuners.

My surging when putting in gear is intermittent now. Once in a while it does it and sometimes it doesnt.

On a positive note. My final numbers were right at 400hp and 400tq corrected on a mustang dyno! I was surprised to see that kind of number. Engine is LS2 with 4L70

inda_bebe

Is this the connector?
C091BE16-8321-4A58-8131-A260AA2BCC28-6706-00000CAFDC08C0EF_zpsad044bf7.jpg?t=1362678696
I started working on my red/blue truck harness and all the colored wires were removed from the PCM, i have the 4l60e and i will be using a aftermarket cable shifter. Is the needed or can it be discardedi

inda_bebe

this came of of one of the blocks, either c2, 152 or 100. how would i wire this up if i wanted to use this?

Pocket

iTrader: (22)

Thats part of it, theres another black connector to go with it

If your aftermarket shifter has a p/neutral switch, then you can delete those two connectors. If it doesnt, you need top retain the two wires pertaining to it

Docked Wage

FWIW, my 2005 L59 (LM7 flex fuel) has never had the PNP switch on it and I' don't get codes nor do I have Idle issues in or out of gear. It's been in for two years now and over 10,000 miles.

Pocket

iTrader: (22)

The VSS can be tuned out completely too

Is it correct? No

Same thing with the P/neutral switch