CamaroSS30thAnn

To start off i dont want to make this a thread that starts arguments between 4l60e and 4l80e I just need "information".

Most of my mods are in my sig if there are any missing that pertain to my question ill let you know.

So a little info:
I have an Lt1 With a 4l80e taken out of an HD truck. I dont know the year or model but can find out if needed bc i believe they have a plate stamped on the tranny that can identify it. IT uses the A TCI computer used in programming it. The transmission had a "performace race rebuild" before it was installed. I seen it being rebuilt so i know it was.

My problem is:
When i first start up my car and go out for a drive i cannot get it to shift out of first into second. It does this for quite a few minutes im assuming until the fluid warms up. As this is happening my speedometer doesnt move either. Sometimes if i slammed on the gas and rev it out as high as it goes it will shift then my speedometer will jump from 0 to what im assuming is how fast im going (somwhere around 30mph). But once it drops back down into first i lose my speedometer and i have to do it all over again. After about 5 minutes of driving itll get better and i wont have to rev as high say around 4k rmps. The longer i drive it the better it gets and it goes back to normal. I can start off from a light the speedometer will work, itll shift as if there was no problem at all. I did notice when the car is acting normal the speedometer seems as if it will take 5mph before it will actually move but everything else seems normal. I just recently got a code P0502 i know what the code is for but where do i go from here? I took a quick look under there i found both VSS sensors and the big round electrical connector. There is so little room under there I couldnt see much but i did notice that the big round electrical connection did have some fluid on it not a lot but some. It was light pink just like the tranny fluid. The only thing i know of above that connection is the output?? sensor but i could not get a very good look at it as the car was on a jack and i couldnt see mcuh above the wiring harness. There is very little room between the tranny and the tranny tunnel. At most 3 inches. Everything else is dry and the conncections show no melting or corroding but i have yet to really get into it.BTW I did check the fluid it seemed fine but then i checked the stick and it said to check while hot and idling and the fluid seemed to dip low so i added some fluid so it will register where it should be when the car is hot and idling. When the car is off tho the fluid on the stick is well above the line it needs to be on. But agian when i check it at hot idle it goes back to where it should be, hopefully i didnt overfill it.

So in endind what could cause this? Should i just change both the VSS and see what happens bc that in its own looks like a task in a half with a 4l80e in a camaro.

Cliff notes:

*Cold tranny wont shift from 1-2 no speedometer
* Sky rev tranny just to get to shift
*Gets better after few minutes
*acts normal when fluid is hot
*got code p0502
*Speedometer does seem as if it takes a second to catch up even when acting normal
*fluid is pink and "full"
* Tranny was rebuilt
*small amount of fluid on round conncection possibly from rear VSS??
*At highway speed the speedometer is 10mph retarded (speedo says 65 in reality its 55)

What do you guys say?

Injuneer

Have you tried replacing the output VSS? Output is the one toward the rear, above the large connector. I would assume this is the sensor feeding the PCM. It also appears that the trans controller looks at the input sensor and the output sensor to determine shifting. If you are getting P0502 and the output sensor is feeding the PCM, that would appear to be the one with the problem.

https://www.novak-adapt.com/knowledg...atic/4l80e.htm

CamaroSS30thAnn

Thank you injuneer. I have not replaced the rear sensor yet. I was looking for opinions first tho this sensor has been on my mind as to try and replace but wasn't quite sure if I should u til get a second opinion. It might take some time but I'll get it done and come back with results..

Mystery Bird

It would seem to me that it's a VSS or a programming issue with the control unit. I used the stock PCM to control mine.

CamaroSS30thAnn

Thank you for all the info guys keep it coming I'm going to go ahead and replace the vss and see what happens. Only one issue here is this doable on the car without removing or dropping down the tranny?. There's not a whole lot of space I'm not sure how far in the sensor go in I'm just worried about space between the tranny an the tunnel.

CamaroSS30thAnn

Alrght guys heres where I am at I cannot get at the rear sensor so well wthout a lift and theres a possibility i may have to drop the crossmemeber to access more room.

I did notice a few tings that did seem odd to me. The round electrical connctor like i said did look to have some kind of fluid that looked like tranny fluid on it but it is completley dry under there,

Snother thing i noticed is that when i remove the electrical connection to the front and rear sensor it was wet on the inside not sure if it was tranny fluid or not but yet again everything was was dry no liquids on the outside of the sensors or around where they enter the tranny its all dry. The tranny has been in there for years and i dont drive it in the rain. Whats going on here.

Also another thing i noticed is when the fluid is cold and and im sitting in my driveway i manually put it into first gear no problem but if i bump it up to 2 it it "clunks" then the car shuts off... Does it everytime, But if i go out driving and get it all warmed up and its running "normal" this does not happen.

Im really beginning to lose it with this car. Are we still betting on the input output sensors here should i even get them chnaged or are we looking at some other kind of scenario?

Mystery Bird

at this point.

Injuneer

I've pretty much exposed my limited knowledge on this subject. The fact that the code sets would appear to indicate an intermittent problem with the sensor or the wiring harness. But that's just a guess.

CamaroSS30thAnn

lol u guys are awesome. I'm going to talk to the tech that rebuild my 4t60e in my van at thr transmission shop. He been there for 40 years so I'm pretty sure he would be very knowledgeable about these situations. I'll also see if If the man that built my tranny is still around. I've been out of the car game for a while bc of my children and haven't kept much contact with most people. I do remember the guy at the transmission shop was real interested in seeing my car bc of the setup so well see what he says and I'll make sure I get back to guys so that it will help you with any future knowledge. In all honesty I have thought about going back to a nice built 4l60e by selling my setup I ha e now but what's the point it's already in there and would be helpful once I start making some good power. Hell I haven't even spray this setup yet

CamaroSS30thAnn

Hey guys just wanted to give u an update. I brought the car to the transmission shop that rebuilt the tranny for my van and got the sensors replaced. The had just enough room where they could "slip" them out and get the new ones in. They had to remove the shift cable and get all the wiring out of the way but they did it without even having to remove the crossmemeber to lower it. Apparent;y they were in there so bad that they both broke off upon removal. Im glad i didnt have to deal with that. BTW i had both input and output sensors changed tho the output one was 99 percent sure to be the culprit.

I have only been able to dive it a few miles but it seem to have solved my problem. Ill keep u updated in a later date to confirm as i drive more.

But for now problem is SOLVED

I know not all trannys are the same but i hope this thread helps someone someday

Mystery Bird

Excellent.

CamaroSS30thAnn

Hey how did u use the stock computer to control the 4l80e I thought that couldn't be done hence y I got the TCI controller

Mystery Bird

I turned a couple codes of, switched a wire or two on the harness and adjusted the shift point accordingly. It was really easy.

Injuneer

Does that mean you are ignoring the input VSS and only reading the output VSS?

Mystery Bird

That is correct.