Transmission lags in drive or third. But not first or second.

[wiltj]

Hey guys, I am having a slight problem with my transmission that I was looking to get some input on

I have a 99 XJ automatic, that when shifted into drive or third, revs up but seems to slip, as the power is not getting to the engine, the truck moves forward but very slowly, and at a very high RPM.

When I put it into the “1-2” gear the car moves fine and with all normal power shift points into second,

Once in second I can shift into third and it works fine,

At a stop a clicking comes from the undercarriage of the car and I am guessing it’s the transmission, its sounds like 2-3 clicks followed by a buzzing noise then 2-3 clicks again.

there is a check engine code however I am beginning to doubt the competence of the shop I left my rig at,

The shop has already suggested a re manufactured transmission, but then admitted they have not even checked the fluid levels. I did this myself and it was brown. So I don’t think they checked the codes either.

I had to leave it up north near dc, and drive back to school in NC so I will be conducting repairs by proxy. Sucks, please help. 

 

[wiltj]

i found yet another post, that describes almost the same problem, however i am lost as what to try next.

my trans is near mile 110k and i don't know what fluid is in the tranny, when i got it almost 2 years ago, i was no niaeve to ask,

here is the post http://www.naxja.org/forum/showthread.php?t=12575

 

[JNickel101]

I'd get your tranny flushed....the AW4 is very picky about tranny fluid. Make sure they use DexIII and not ATF3 or 4.....

 

[lawsoncl]

Start by checking the fuse for the tranny computer. If it doesn't have power, you get 4th gear is (D), 3rd in (3), and 1st in (1-2). Pulling this fuse is s actually the first test in the service manual, then shift manually using the shifter to verify the tranny is fine mechanically.

By all means, check the codes as they will likely point directly to the problem. If it's just a P0700 code and nothing else, that usually means the tranny computer isn't responding.

Skip the flush, btw. It's more likely to do harm than good.

 

[hidesintrees]

my jeep has the same exact problem! i put it in D and its in 4th, in 3rd its only in 3rd, and i have no 2nd gear cuz 1rsst wont shift. is it really just the fuse?! or do i need a new tcu?

 

[clunk]

check the fuse first, it's easy to get at under the passenger side dash (below the glove box). I remember reading that the TCU is a pretty bulletproof unit and is designed to last forever as long as it doesn't get swamped with water.


If you have a blown fuse or faulty TCU and it's been stuck in "limp mode" for however long, I would be a little worried about the excessive heat it has been creating if you are starting off in 3 or D though, since the tranny has to really rev before it will get going. I think the general consensus is that the AW4 is pretty much bombproof as long as it doesn't get too hot.

For the time being, you should be able to drive it like it is in "limp mode" as to not cause any more damage. Start out in 1/2 and rev it to around 2300RPM, then shift it to 3, then to D if you need to. You are basically driving it like a standard at this point. Just be careful to not leave it in 3 or D when you pull away from a light or stop sign, as this will just cause more heat, more friction and possibly more damage to your transmission. The torque converter will also not lock up without the TCU working, which isn't a huge except you'll notice a decrease in gas mileage.

 

[lawsoncl]

my jeep has the same exact problem! i put it in D and its in 4th, in 3rd its only in 3rd, and i have no 2nd gear cuz 1rsst wont shift. is it really just the fuse?! or do i need a new tcu?

Quite possible it's just the fuse. Actually I'd say likely as it's fairly rare to have a bad tcu.

Your profile says 1990, which I believe has the fuse in the wiring harness right up near the tcu. The tcu is located under the passenger side of the dash. If you stick your hand up just behind the lower kickplate you can feel it. It should have a big connector and a wiring harness going down and up through the firewall. The fuse sticks out of or is taped to the wiring. If you have a meter you can verify that you have +12 volts at the connector on both the red and yellow wires.

 

[hidesintrees]

well heres my lowdown, but first thank you for helping me out im so happy that i finally found some possible answers! up untill now anyone ive asked has just looked at me like im an idiot...
it had the 90 aw4-someone hacked into the tcu wireing and put a shift lockout switch in (before i bought it) to get 1rst in 1rst and 2nd in 2nd for the trails. i cut the switch and replaced the tranny with a 95 tranny everything bolted up fine the way it was supposed to; however, i havent had a chance to really test drive it because i installed an sye kit and dont have a rear driveline so anything ive testd has come from moving 10ft in my drivemway in 4x4.
i will drain the pan check out the solenoids and replace the filter and then check out all the adjustments that didnt know about, first the fuse though, thanks again