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Torque Converter Question

V

Virginia John

NAXJA Forum User
Location
Martinsburg, WV
I have noticed at highway speed when you let off the gas the torque converter has unlocked and when you reapply the gas the torque converter relocks (based on the tach). It gives the sensation that the transmission is slipping. This doesn't seem right to me. Is it possible that the torque converter is going bad? The Jeep has 124,000 miles, fluids are changed regularly and is at the proper level.
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I think that is normal as some speeds and more noticable with a loud/er exhaust. The important thing is, it locks when you are on the gas pedal.
 
happens on all of mine too, if I let off the throttle for a short period (not sure, somewhere between a tenth of a second and two seconds, I generally don't let off the throttle) the torque converter will unlock.
 
Interesting. My 87, which is now working properly for the first time in 7 years (since I bought it), stays locked up, unless I get close to WOT, and then it only unlocks for 1 second as it down shifts gears. Even with the brake applied mine stays locked until the engine RPM is down to 1100 and vehicle speed is down to about 20 MPH (or a little less).

I have a dash light installed on mine to confirm TC lockup.
 
1987 had a TCU with different characteristics than the later models. In 88 they changed it. One thing they changed was torque converter lockup and shift sequence. 87 shifted 1,2 ,3 , 3+lock converter, OD, OD+lock converter. 88 and later shifted 1,2,3,OD, OD+lock converter.
 
cruiser54 said:
1987 had a TCU with different characteristics than the later models. In 88 they changed it. One thing they changed was torque converter lockup and shift sequence. 87 shifted 1,2 ,3 , 3+lock converter, OD, OD+lock converter. 88 and later shifted 1,2,3,OD, OD+lock converter.
Click to expand...

now that's an interesting tid-bit of info I've not heard before! I'm guessing my '88 has had the TCU swapped at some time then. I can feel six rather distinct RPM changes if I slowly run up to highway speed.

--Do you have a list of TCU part numbers associated with the '87 model year?

--Didn't the ECU get improved for the '89 or '90 year as well?

I'm thinking the '90 ECU with the '87 TCU might net better fuel economy with crappy gears and bigger tires (running in 3rd most of the time) and less slipping of the converter might generate a little less heat in the trans. fluid.
 
No list of TCU numbers. I happen to have an 89 TCU I could get the number off of. I don't think the TCU changed after 88.

88 ECU improved a bit over 87. That's where the HP was increased from 173 to 177. 89 and 90 ECU equipped Jeeps had 182 HP from an ECU change. Those part numbers end in 428.
 
My 98 stays locked until the load drives the TC to unlock. Sequence is: unlock the TC, then downshift to 3rd if required. The TC will lock up again if I lift the throttle.

Could be that I use less throtle than most so the TV valve is playing in the mix. But I did run out to the hiway and check it...
 
Virginia John said:
Where should I be looking - TPS, TCU, Torque Converter?
Click to expand...

TPS, Trans fluid level, the brake switch, other TCU and trans connectors and wiring, solenoid #3.
 
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