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No 1st?

M

Muddy89XJ

NAXJA Forum User
Location
Mansfield, Texas
I have been having transmission problems for a while now and i still cant figure it out. First the transmission would shif into some gears and not others, so i pulled the TCU fues, everything checked out ok. I checked the TPS and it was shot, so i replaced it along with replacing the tranny fluid and filter (it was due, super burnt) and that helped out a little bit but it still wasnt right. So i checked the solonoids and one was bad so i replaced all of them with new ones. and it didnt change anything. Im at a loss, when you take off the first time, first works, second works, 3rd wont go till about 3k and half throttle. then as you come to a stop it wont go back into first unless you restart my Jeep. I dont have the money to just throw at it, any help will be appreciated. I also checked the tps again, and its adjusted close enough to where it should still shift on time, and goes thru the voltage with no hiccups. Can anyone help me?
 
check the throttle cable that goes to the tranny, it may be lose/broken/almost broke.

and check the connections for the tranny wires...right side of the engine at the firewall, just in front/to the side of the dipstick tube.

if those don't work, check the connections at the tranny computer...perhaps they are corroded, or the computer is bad.
 
ive checked all that, and cleaned them just to be sure, it did nothing.

Someone told me that a malfunctioning speed sensor could be it cause it would tell the tcu that im still moving thus not letting it go into first. If its that, what one would i test, theres one on the output shaft on the tcase and one on the back of the transmission. Im assuming that id test the one on the back of the transmission. What purpose does the one on the tcase serve. Im sorry im asking so many questions, but im eager to fix my Jeep and get it
up and running right again.
 
Muddy89XJ said:
I have been having transmission problems for a while now and i still cant figure it out. First the transmission would shif into some gears and not others, so i pulled the TCU fues, everything checked out ok. I checked the TPS and it was shot, so i replaced it along with replacing the tranny fluid and filter (it was due, super burnt) and that helped out a little bit but it still wasnt right. So i checked the solonoids and one was bad so i replaced all of them with new ones. and it didnt change anything. Im at a loss, when you take off the first time, first works, second works, 3rd wont go till about 3k and half throttle. then as you come to a stop it wont go back into first unless you restart my Jeep. I dont have the money to just throw at it, any help will be appreciated. I also checked the tps again, and its adjusted close enough to where it should still shift on time, and goes thru the voltage with no hiccups. Can anyone help me?
Click to expand...

ok, wow so im not the only one.... well my trannys doing the same thing...(i have a TJ) but yea mines doing it with all the gears.... im taking mine to a (trans) mechanic tomorrow to look at it ill let you know what he says... he told me today that jeeps ,XJs TJs and YJs have common trans problems
 
it's the one on the output shaft of the t-case. I'd just replace it and see.

there's only 1 speed sensor, any other "speed" sensors are more like tachometers...which there is only one of and that's on the engine.

the other sensor on the tranny is the NSS switch
 
ok so i took my jeep, they cdrove it and hooked it up to a machine and looked over it. they found little scraps of metal (tiny) could only get with a magnet...for me it was my gearing was striped.... take it to a trans place to look at it,:dunno:
 
stimulatechamind said:
ok so i took my jeep, they cdrove it and hooked it up to a machine and looked over it. they found little scraps of metal (tiny) could only get with a magnet...for me it was my gearing was striped.... take it to a trans place to look at it,:dunno:
Click to expand...

i did the other day to see if they had any insight and they told me pretty much what i knew. i know its not mechanical cause i unplug the tcu and gears work fine.

Jeepcomj: Theres two IIRC. these one on the top part of the rear of the drivers side of the transmission, and then on the output shaft of the tcase. I guess ill search how to test it, cause i dont have any money to just throw at it. Money is really tight right now.
 
Last edited:
I just posted some instructions for checking the tranny speed sensor here http://www.naxja.org/forum/showthread.php?t=919015.

Normally a failed output shaft speed sensor produces no pulses and the computer thinks you are not moving. On 1998 and later, btw, there is a n additional sensor for the input shaft so the trans computer can diagnose speed senosr problems and shifting problems.

The sensor on the xfer case (or tailcone for a 2wd) is for the speedo.

Based on your symptoms, it sounds like a bad shift solenoid, but you just replaced those right?
 
lawsoncl said:
I just posted some instructions for checking the tranny speed sensor here http://www.naxja.org/forum/showthread.php?t=919015.

Normally a failed output shaft speed sensor produces no pulses and the computer thinks you are not moving. On 1998 and later, btw, there is a n additional sensor for the input shaft so the trans computer can diagnose speed senosr problems and shifting problems.

The sensor on the xfer case (or tailcone for a 2wd) is for the speedo.

Based on your symptoms, it sounds like a bad shift solenoid, but you just replaced those right?
Click to expand...


yea and they werent cheap. i dont think its a solonoid cause 1st works when you first start off. ill check that seed sensor tomorrow and post back
 
unplug the tranny fuse and manually shift it. it will shift from 1 to 2 but not into 3 manually without the computer powered. if it does that, then it's the computer that is shot.
 
strange
 
if your tps isn't working right, then your whole truck wouldn't work right.

check all the connections?
 
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