Hello this is my first post. Hope I do it right.

I have a 1990 cherokee larado 4.0, auto trans . Getting it ready for deer season! My questio is----does a 1990 cherokee auto trans have a locking torque converter? Mine does't seem to lock up 1:1 . At 55 if I pess the gas to go faster the rpm's rise more that the speed. On my dodge truck when i go faster the rpm's are in sinc. with the miles per hour.

1. Does mine have a lock up torque converter, or
2. If so, what could cause it not to work?

Thanks

I will post pics soon.

 

Your XJ should have an AW4 transmission in it. If I'm not mistaken all AW4's have lock up converters in them. The first thing that comes to mind is engine temp. and temp sensors. Most vehicals with lock up converter's will not lock up until a pre-determined temp is reached. Beyond that there could be any number of reasons it doesn't work. I'm sure others will have some ideas.

 

Easy way to sense it unlock is get goung 50MPH on flat or even slight downhill so there is little load on the engine. Keep the pedal steady, then lightly press the brake pedal and watch tach and listen to engine. The lockup should unlock and engine RPM will rise instant and you will hear it. stay on brake it stays unlocked. let of brake and it should instantly lock. repeat as you wish.

 

Thanks
I will check those things out tomorrow. Thank you for the info

 

I do have a aw4 transmission. But have driven 65 mph dowhill and it still want lock up. When other locking tc's lock I can fill it like a gear change and see the rpm's lower. then if I press down on gas petal the rpm's will not rise more than the mph because of the 1 to 1 lock up. When not in lock up pressing the gas will make the rpm's rise more than mph.

Checked trans fluid and topped off, no help.

I'm going to google for more info, but if anyone has other thoughts please reply

Thanks

 

When was the last time the fluid and filter were changed? That would be my first suggestion. Next, go to a local parts store and have them pull the engine codes for possible transmission codes. You could have a bad shift solenoid.

Good Luck

 

did you try the brake tap thing I said? It could be your brake switch is faulty or needs adjusted. Does the cruise work? Cruise wont work if brake switch is on I assume.

 

my 90 is doin the same thing and my cruise does not work and mt tc dont lock

 

Hi and welcome to CF..
I wrote a writeup on manually locking your TC if you want to try that to see if you can get it to work...Tj
https://www.cherokeeforum.com/f51/ma...rter-tc-14114/

 

Back again to update on my 1990 cherokee aw4

Tried the brake petal lift - did no work--SO

I went ahead and installed the switch between the yellow and white/black wire on my TCU ( under passnger dash panel ). Works GREAT --Thanks for your support and feedback. This is a great forum for Jeep Cherokee owners.
Something else I did was install a switch so I could control the electric fan. Previous owner tried to wire direct but it didnot work. That works good.

This is my hunting vehicle and I have been getting it ready
New tires
Fixed Locking Torque problem
Fixed fan
Changed fluids and filters

Changed locations of the vacuum canister that was behind the bunper on the passenger side due to a crunped fender. Connected vacuun lines , now my air blows correctly.

Did not get a door key with jeep- parts stores show wrong door cylinder lock when looking up a 1990 model-- SO had a lock smith make a new key for $15 ( I had the lock cylinder from the drivers door removed already ) now I can lock all doors and hatch.

Cleaned a clogged ccv on the valve cover to stop it from blowing oil out the filler lid and into the air filter. Now no oil on top of motor.

Have one other leak to fix, I think it is the distributer base? working on it.