AW4 experts...what's going on ?

[kastein]

oh yeah. I forgot. Before you fool around with that so much like I suggested, measure the resistance from ground to the torque converter lockup solenoid pin (with the TCU unplugged.) If it's over (IIRC) 15 ohms by a significant amount, the solenoid is probably dead.

 

[TRCM]

kastein......that would be @ C14 right ? and you mean from D7 or from a known ground ?

Also, this switch would be on the opposite side of the TCU from the brake switch, right ?

 

[TRCM]

OK,

D7 - C14 gives 15.3 ohms

C14 to known good ground gives 5.0 ohms

So maybe the solenoid isn't bad ?

 

[kastein]

I forget what pin C14 is - is that the torque converter lockup solenoid?

 

[TRCM]

Yes, per this link


http://www.transonline.com/transDigest/magazines/1997-10/Shift%20Pointers/index.html

 

[kastein]

That's rather odd. Sounds like there is probably an issue with the grounding (cruiser54 is probably right on where that problem lies) and possibly also a shorted or burnt out solenoid. I'd expect 11-15 ohms or so from a known good ground (D7 is SUPPOSED to be known good) to each of the solenoid wires, C14/15/16. Since you get a different (significantly different) answer between a good ground and D7 it makes me suspect the grounding. Check the other two solenoid resistances though? I'm curious. I'm betting on something like 20+ ohms on the other two solenoids, assuming they are both functional since it shifts properly now.

 

[TRCM]

solenoid 1 D7 - C16 13.2 ohms C16 - good ground 5.2 ohms
solenoid 2 D7 - C15 12.9 ohms C15 - good ground 5.3 ohms

D7 to known ground gives 0.0 ohms so somewhere between the D7 & the C14/C15/C16 is a ~ 9 ohm issue



shifts fine now, just no lockup

kickdown could be better tho, but my 96 has me spoiled...just breathe on it and it kicks down

 

[kastein]

wait, volts or ohms? you listed volts. If you meant ohms those are both fine.

It is really odd that it gives 15 ohms from D7 to C14, but 5 ohms from C14 to a known good ground and 0 ohms from D7 to known good ground. Something seems fishy about that.

 

[TRCM]

should have been ohms for all (fixed it now)........and the TCU is unplugged

Just went and triple checked all readings....variance is ~ .1 ohms

 

[TRCM]

Ok.......went out today and worked on it some more

1) replaced the ground strap from the firewall to the block and cleaned all connections
2) cleaned the trans connecters by the dipstick tube
3) wired in a temp switch for tcc lockup

Now, when I am in gear, the TCC seems to lockup using the switch (based on speed change with no rpm change), but will have to see how it does on the road, and not just with the rear axle on jackstands, since there is no load that way.

 

[DrMoab]

Check your brake switch again. DaveW here did a manual to auto swap on an 89 and missed a plug for the brake switch. It caused exactly the trouble you are having with the lock up.

 

[Ecomike]

You should see a 400 RPM drop at constant vehicle speed on the road test

 

[TRCM]

Well, good news, I think.

The lock up switch I installed definitely works, and I've already gained back ~ 1 mpg. 60 mph is ~ 1700 rpm now.

But, I noticed if you have it engaged, and you start going down an incline, the trans starts bucking a little. Onbly way to stop it is come completely off the gas and get back on it easy. Trying to slowly let off doesn't work.

I'm not sure what's going on there, but it almost feels like the trans mount is made of rubber bands.

 

[cruiser54]

Sure it's the trans causing the bucking and not an issue with your secondary ignition like plugs, wires, cap and rotor?

You need to do a good visual inspection on both your engine and trans mounts.

 

[Ecomike]

I had the bucking recently even on a flat run with the TC locked up...... and it turned out to be conductive dust inside the Cap, and corroded/eroded tips on the rotor and cap. Cleaned it all, and no more bucking now. It only bucked giving it gas while the TC was locked up. So yes, check everything from the HV coil to the spark plugs. I would also check the TPS at some point. Bad mounts might make the shaking more extreme.

 

[cruiser54]

Ecomike confirms my suspicions......

 

[TRCM]

It does not buck when the TCC isn't locked up, which is why I suspectd the trans and /or trans mount.

But, it is under more load, so I will see what I find and post back the results.

It may be a while, as I only drive this cherokee when I go hunting, so basically the weekends.