At 106k, I am one cranky chick, my AT feels as though its failing and I need help in diagnosis.

POINT ONE: NO CODES SPIT OUT BY THE ECU.

THE ISSUE:
She doesn't shift at the proper RPMs, in fact from a stop ...to get into 2nd I either let her hit 4k/rpm or let completely off the gas at 2k. There are no problems in any other gear EXCEPT when I'm cruising the highway at 60 to 80MPH- the engine screams and she sits at 3k/rpm no matter how fast or slow i cruise. She just sits there at 3k like somthing is holding her back. Decelleration causes NO issue...what the heck? NO leaks either.

Since I have nothing to lose, I went ahead with a tranny flush and added Lucas Oil- NO difference afterwards. I wanna try all options before a tranny rebuild obviously...and the symptoms are stumping me.

Perhaps its the Throttle Position Sensor malfunctioning?

Perhaps its the solenoid pack not receiving the proper amount of voltage?

Perhaps its the differential pinion shaft being worn to bits?

What should I start with first?
Any advice or a similar experience with the AT is greatly appreciated!

 

Well I think you are going to have to face it, your tranny needs attention. It is not the TPS, that's got nothing to do with the symptoms you describe.
Using logic:
The transmission doesn't want to change into a higher gear except at rpm's very much higher than normal. I have doubts that this is an electronics problem. Seems to me that it's going to be the valve body or the transmission oil pump. The symptoms do not fit a problem with the TC; I'd guess the turbine is perfectly ok. No slipping evident, so probably the clutches are also in good condition. Take it to a transmission specialist first, to see what they diagnose.

 

take it to a transmission shop, it might be a bad connection. I had a bad connection on mine but that is after i put a whole tranny in.

 

I guess I'll try a transmission shop. Let you know what they say.

 

Best of luck. Those symptoms on my car equalled a fried tranny. When you changed your fluid out what colour was it? If it wasn't pink and smelled burnt...

 

Nah...surprisingly it was a promising redish color...that's why i hoped for an alternative diag. I will hit Aamaco this weekend anyway.

 

um..well if anyone else has tranny issues i found another diag...connectors which later develop into slipping issues...I'ma try that and run a TCU diag tonite:

"I had this veeery soft gearchange which (I guess) could develop to slipping. After all connectors cleanup, all slipping vanished from my transmission.
Conduct connector cleanup. One major cause for slipping is the oxidized connections that starve the actuating hydraulic solenoids inside the tranny..."

 

Sounds like bad selonoids in the trans. My friend had that problem in his 95 max, it wasn't shifting right at certain RPMs and speeds. Could also be the speed sensor on top of the trans, not functioning or time to time. I would get a VLSD from a 1st gen I30, around 400-500 if you have to replace it, just need drivers' axle.

 

Thanks Tim...guess i'll find out tomorrow as I bring the max into the trans specialist...i better clear my other codes (o2 and knock) before they freak out.

 

Well I ran the codes myself...

PO600 - AT communication line
PO734 - 4th gear failure or Torque Converter C. Signal

and ofcourse the knock sensor was thrown by the prior codes.

I went through the service manual trouble shoot leading to 4 possible issues:
1. the TPS - which btw i changed myself...it cost me about a hundred at the dealer and I simply thought cheaper than a rebuild. It didn't help though...big surprise!

2. The Control valve

3. The solenoid valve/ assembly

4. My tranny's screwed and i need a rebuild.

So I decided to get another opinion from tranny specialist and the guy just ran the same freakin codes I did. I mean c'mon, I told the guy i wanted to replace the control valve and the solenoid valve assemby after conducting my own diag and he does the same. His diag suggested that I replace the Torque Converter and a rebuild ...with a final cost of $1,500-1,600.

I think I need a second opinion. I mean if the TCC were freakin blown wouldn't i be having huge issues like getting the car into R or any other gears? I mean- I ain't a genuis but doesn't the TC send power from the engine to the transmission via fluid?! Then he goes on to say he checked the fluid and it smelled burned and it was brownish...hello--- I changed the fluid the otherday and i checked it myself...blood red!!!! Besides, I only have an issue with getting into 4th period...and then it runs to 3k before it shifts into 2nd! Feels like something is stuck in the valve!

HELLLLLPPPPP MEEEEEE! I'm defintely bringing it elsewhere for a second opinion, But i'm open to suggestions.

 

BUMMMMMMPPP!

So I called another local mechanic for a second opinion and he was smart and honest. He said even if it were the control valve or solenoid valve ...it would just get lodged down the line with shards of my tranny...re-clogged and more tranny problems. I'm bringing it to another transmission specialist for a second opinion this afternoon.. recommended by that same mech.

SWAP...or REBUILD or replace the valves? I DUNNO!

 

I've seen a lot of connection problems with the brown connector that all the trans signals go through. Especially if it's ever been touched. You might want to ohm out all the connections before you rip the trans out.

 

You mean the one behind the center console?