4l80e shifting ?

[mooseknuckles]

has anyone had any problems with the 4l80e shifting?....for whatever the reason my trans will not stay in first gear for anymore the a few seconds...whenever I take off it goes the length of the truck or so and shifts into second gear. even when I try to manually shift it same thing...doing a burnout it shifts into second after a few turns of the tires...is it something in the tune?..the pcm was reflashed for 3:42 gears and 26" tires. I have the right gears now but my tires are 28".....it still as the stock van converter, and a TCI shift kit...and it shifts realy hard in all gears, even fourth.

[mcmlxix]

I think it depends on the year and what operating system is on the ECM/PCM, the software may be able to adjust shift points. Talk to the person that tuned your ECM, see if they have any info about your tune.

[flamingbig10]

did you check the speed sensors if they were hooked up correctly, because mine did the same thing I had the connector swapped input speed signal was reading the output sensor and the output speed signal was reading the input senor

[BR3W CITY]

was there a wire in the connector wrong?
I've had o/d issues and I'm curious about the vss connection.

[Gordonr1973]

Moose:

- check out my other 4L80E thread

- what do you have for trans connectors on that harness

[mooseknuckles]

Originally Posted by Gordonr1973

Moose:

- check out my other 4L80E thread

- what do you have for trans connectors on that harness

heres a pic with the connectors....I think every thing is hooked up properly, the wires aren't long enough to be switched around...

[clinebarger]

Originally Posted by mooseknuckles

heres a pic with the connectors....I think every thing is hooked up properly, the wires aren't long enough to be switched around...

That doesnt mean they are not switched, You have a untested aftermarket harness,

[Gordonr1973]

Originally Posted by clinebarger

That doesnt mean they are not switched, You have a untested aftermarket harness,

Is your spedometer reading anything when you drive?

[mooseknuckles]

Originally Posted by Gordonr1973

Is your spedometer reading anything when you drive?

speedo's not hooked up...I'm using a GPS for a speedo.....

[BR3W CITY]

^ would the pcm throw a code, or not even know they were switched?

[mooseknuckles]

so now what do I do?.....I dont have anything to read the codes with....

[clinebarger]

Originally Posted by BR3W CITY

^ would the pcm throw a code, or not even know they were switched?

Nope, The PCM wouldnt have a clue.

[mooseknuckles]

so I should try switching them around??

[clinebarger]

Originally Posted by mooseknuckles

so I should try switching them around??

Yes, It wont hurt anything, & would atleast rule that out. Untape the harness if necessary, Dont pull on the plugs.

[mooseknuckles]

ok...I'll give'r a try tomorrow...Jon@PSI wasn't very helpfull.

[Gordonr1973]

look on kijiji for a obdi II code reader

maybe if you bought / borrowed a Superchips programmer you could use that to read codes with? -- I'm not sure about that one though

Can Tire had the OBDI II on sale last week up here, maybe down there they would still honor the sale price?

My new S&P harness has all the tranny connectors on it (there are at least two more from memory that connect to the black plastic module that your shift linkage will pass through into the transmission.)

I drove the truck last night through the gears, shifting was normal and I will get it out on the highway today to check shifting into O/D.

Will it shift into other gears normally after going to second?

I would check your brake switch by the column to see if your connections are correct for the TCC lock out / disengage (if that is the correct terminology) when the brake pedal is used.

Don't worry, for every problem there is a solution, we just haven't got there quite yet on this one!

[mooseknuckles]

Originally Posted by Gordonr1973

look on kijiji for a obdi II code reader

maybe if you bought / borrowed a Superchips programmer you could use that to read codes with? -- I'm not sure about that one though

Can Tire had the OBDI II on sale last week up here, maybe down there they would still honor the sale price?

My new S&P harness has all the tranny connectors on it (there are at least two more from memory that connect to the black plastic module that your shift linkage will pass through into the transmission.)

I drove the truck last night through the gears, shifting was normal and I will get it out on the highway today to check shifting into O/D.

Will it shift into other gears normally after going to second?

I would check your brake switch by the column to see if your connections are correct for the TCC lock out / disengage (if that is the correct terminology) when the brake pedal is used.

Don't worry, for every problem there is a solution, we just haven't got there quite yet on this one!

I'll have to check out canadian tire for that....I can manually shift 2-3 and 3-4, but I cant shift 1-2 manually because its already shifted by then.....as for the brake switch it seems to be working, when I hit the brakes you can feel the converter disenguage.... I'm sure someone knows the answer...just a matter of time...meanwhile I've been talking to Jon at PSI.....I'll let you know how thats going.......

[mooseknuckles]

I'm not 100% sure what the mph is when its shifting (maybe 10mph) but, when I'm at a stop sign and drive off, its already shifted into second by the time I cross the street.....

[68GMCCustom]

You need to get a scan tool...even if its just a $50 one that only reads and displays codes. I was using my Aeroforce Interceptor I had put in our TBSS a few years ago, just pulled it out for the truck. It reads codes as well as clearing them, plus a bunch of other stuff.





Since then I purchased HP Tuners....its a full on ECM/TCM scanner and editor. Wow....if your interested in performance and have efi........ you need something like this.

[Gordonr1973]

No O'Reilley's up here :-)

But Canadian Tire might lend you a code reader b/c they have that 'lend a tool' program in their stores.

Wouldn't hurt to call. I was supposed to be in Ottawa for meetings this week but they got cancelled & moved to Toronto, otherwise I'd pop by to help you!

[mooseknuckles]

I'll def have to look into that gordo....Im almost 100% sure it needs a tune to fix it, because of the shift kit...and not too many places around to get it tuned at....so I've been looking at buying a HP tuner.....also have to check the voltage at the TPS.

[Shon]

The trans shifts based on MPH; the PCM needs to have the correct Gear/Tire size no matter what is driving your speedo.

[mooseknuckles]

Originally Posted by Shon

The trans shifts based on MPH; the PCM needs to have the correct Gear/Tire size no matter what is driving your speedo.

...so what about the shift kit?...I've read that it affects the pcm's programing?

[BR3W CITY]

the shift kit would change the solenoids and the physical pressure in the trans/valve body, I don't think it would change the pcm program directly, instead that it would require the tune to take into account the fact that a shift kit was added, and change pcm parameters/shift points/firmess/traction control (if applicable)

[mooseknuckles]

I've read that some of the numbers in the tables have to be changed or "zero'd" when running a shift kit...so I'll have to look in to that more....but right now I need to find someone that can do a tune, or someone that knows whats going on more that what I do...(which isn't much) to fix my problems.....first gear shifts way too early, overdrive shifts late, and every gear shifts super HARD!