I noticed today that when i'm at 40-45mph my rpm is at 2000-2500 rpm. Am i stuck in 3rd gear? The 4th gen gets into 4th gear and the rpm goes alittle below 2000.

P.S. i just installed a new 2.5" exhaust from y-pipe to muffler.

 

is your overdrive OFF, OD OFF on the dash?

 

over drive is on, i tried taking it off yesterday and that takes my rpm to 3000-35000 rpm at 40-45 mph

 

at 45mph, the 3 gen may not be locking up the torque converter so the engine rpm may still be higher.

both cars have nearly identical final drive ratio and same 4th gear ratio, so they should read within 100rpm or so at same speed.

try getting it out on the highway and cruise at 60-70 for a few miles and get some heat into the transmission. once it fully warms up to operating temps, they should run just about the same rpm.

 

This morning i was able to count the shifts and it went into the 4th gear, however the 4th gear shifts from 3000rpm to about 2000-2500rpm. I did about 75 this morning on the way from school to work (roughly 30 mins of driving). Could this high rpm be caused by a 2.5 exhaust or the car ignition timing being off?

 

Neither would cause that.
sounds to me like the torque converter isn't locking up for some reason.
even in sub-freezing temps in winter, it should lock up after about 10 min of driving.

 

I think I have the same problem. I call it the pseudo-shift. My car pseudo-shifts between 35 and 45. But at 65, I'm at 2.5 krpms.

 

..new tranny? Or is it fixable?

 

The lock-up converter is both temperature and load dependant amongst other things - When the box is cold it will refuse to shift to overdrive and also lock-up if the speed is too low ................. once you get to the normal op temp, the box will shift to overdrive and lock-up the TC (see FSM) - if all is working as per design you should be seeing around 120kph/75mph @ 2500rpm on the VG once normal op temp is reached at constant speed.

As for the rest - its gonna be an absolute function of temp, load, throttle position and speed as I said and your results will undoubtedly vary

 

75 = ~2500 rpms instead of 65
I not sure what it means for my tranny.

 

Well - not much more I can say or suggest to help unfortunately.

Get on the highway with both the motor and box at normal op temp (drive around 10miles with ambient around 20C) and when travelling at a constant 75mph on a flat surface you should see 2500rpm (VG box anyway) ..................... if you only see 65mph then I guess one could say your TC isn't locking up or you are not getting into overdrive (if you have a VG with std wheels and the OD switch on your selector is working - and assuming you don't have a custom fancy ratio box or TC with non-std stall speed with the over-dive light on the dash off).

Guess its time to acquaint yourself with the extensive fault-finding trees in the FSM on the auto boxes

 

Update:
The RPM drops alittle below 2000 RPM at 45mph when i enable cruise control.

Edit:
Here's a pic with cruise control on.

 

Extrapolating from that pic:

(44/1900) x 2500 = only 58 mph@2500rpm ................so some thing's funky. Post the same pic @ 75mph (TC and overdrive MUST be working there when box is hot - perhaps 45 is too low)

Do you have a GPS or mobile with GPS functionality that independently can confirm the speed seen on the dash?

 

Thanks for all your replies.
I double checked my speed with an iPhone app and also with a NY speed radar. My speedo is correct.

So it's official my torque converter is not locking . I'll get a fsm and go through the diagnostics..if that doesn't work I'll take it to tranny shop.

 

update:
Didnt get any codes when doing tranny check from fsm. I went ahead and changed my throttle position sensor, the old connector had green corrosion, so i cleaned and replaced with a new TPS... this didnt fixed anything

heres a video, i was driving for 30mins. I believe i had cruise control on.
http://www.youtube.com/watch?v=MCRKIDQE-O0

i'm also getting 160 miles per tank

 

You still have not responded to this.

See the table on FSM AT330 - TC lock-up specs - 40mph is IMO too low to judge ................... imo 40mph is just about guaranteed NOT to cause lock-up[

 

I'll be hard for me to take it up to 75mph, i'll see what i can do over the weekend if i find a nice long stretch of road. Cops are cracking down in long island highways for speeding But i just read page 330 and you are right, would it be the same if i jack the car up and take it to 75mph?


Thanks
Khemraj.

 

If you are stuck in an area where you can never actually reach a speed to satisfy the lock-up pre-conditions then you are chasing your tail here - it simply will never lock-up. Yes it may cause your bad fuel consumption as a result.

2500rpm constant on the ground or in the air will result in the same indications on the dash. If you have to do it this way make sure both front wheels are off the ground to prevent the diff having a cadenza (or if you have a LS unit in there somehow to make that cause the car jump off the supports) - IMO this is unsafe practice but there you go

 

Just make sure the car is VERY well supported (good jack stands and wheel chocks on the rear) and there's nothing in front of you to nail, and you can do it..
I do this all the time on my race car when I'm checking for drivetrain vibrations and when switching differentials.

drive it around for a good 20-30 min to get everything nice and warm, then pull it into the driveway and jack it up and such.

 

my car used to lock up at 45mph on 1-10% throttle. if he can get it to 50mph then it should lock up for sure, if it's ever going to.

thing is that running the car up in the air is that without any load to put a drag on the unlocked TC, the RPM difference between unloaded unlocked tc and unloaded locked TC might not be noticeable since it takes practically no power at all to make the wheels spin in the air. whereas it would be a noticeable difference with the wheels on the ground pulling the weight of the car around locked vs unlocked especially up a very slight hill.

i have put the car up and run it in the air before tho... biggest thing besides improper support that will mess you up is unbalanced wheels.. kinda makes the car feel like it's gonna fall apart if they are vibrating about with no weight on them to dampen it.

 

As I said - never had the want/need to check the TC in this way but if its in the air as per the experiment, I would say that you can slowly chase it up to 80mph in "power" mode and let go of the throttle ............... the unlock point as the speed drops will then surely be noticeable, but IMO find a proper flat road is the correct answer

 

Update. Last night i drove the car for 30-35 mins up and down the southern state parkway at 45-50 mph. After i was confident that they werent any cops around i took the car to 75mph. The RPM at 75mph is around 2800-3000. If i give it more gas, the RPM rises and so does the speed. I drove it steady at 75mph for about 15mins. I'm sorry i couldnt make a video of this, i felt it was a bit too dangerous to so.

Also RE: the transmission diagnostic, i'm a bit confused with a few steps:

Step 1: Start engine and warm it up to normal operating temperature

Step 2: Turn it off and set the Power/Comfort to Auto ( So while warming it up from step 1, i should put it in either comfort or power so when it turn it off, i put it in auto?)

Step 3: Set over drive switch to on ( Same goes for this as step 2? Set it to off while doing step 1?)

Step 4: Set gear selector to P (Wouldnt this be in P already? since i had to start the car and warm it up??)

Step 5: Turn ignition to ON and power indicator should be on for 2 secs

Step 6: Turn ignition to Off

Step 7: Push shift lock release button and move to "D" (Is this the big button to the left side of the gear selector? Or inside/under the gear selector/trim? If its the big button to the left, then the ignition needs to be in the ON position before i can move the gear selector to "D")

Step 8: Set overdrive to off position

Step 9: Turn ignition on, wait for more than 2 secs after ignition switch "on"

Step 10: move selector level to "2" range

Step 11: Set overdrive switch to "On" position

Step 12: Move selector level to "1" range

Step 13: Set over drive to off position

Step 14: Depress Gas fully and release it

Step 15: Power indicator lamp will bling codes...hopefully.


Sorry for the long post, i'm going to try this diagnostic again today, but want to confirm it.

Thank you very much,
Khemraj

 

Then you have a non-locking TC ..................... time to drag the AT section of the FSM closer and start following the excellent fault-finding trees

 

Been there done that
I'm gonna save up and get the car fixed by a tranny shop or see if I can buy another tranny.