What would be the symptoms of a torque converter that was stuck in Lock-up for an AOD?

 

If the converter is stuck in the lock mode, when you pull up to a stop light it will die unless you put it in nuetral, basically like a manual if you don't use the clutch. If for some reason it makes it around that, it will be a real dog until around 30 mph or so.

 

Yeah, my symptoms are I can put it in D or OD and it will eventually bog down unless I put it in P, R, N or L. If I manually take it through the gears it appears to shift quickly from L to OD as soon as I come out of L.

 

Take it for a drive, if you sit at a light with your foot on the brake and the tranny in anything other than N or P you will kill the engine if the converter is still locked. Sounds more like a converter lockup solenoid going bad. It is letting the converter lock before all the requirements have been met. Generally the coolant must be 130 degrees, the car doing more than 24 mph/the tranny in either 3 or OD, somewhere around 20 inches of vacuum (no heavy loads on the engine) and your foot off the brake. Sounds like the solenoid is going anyway, or there is an issue with one of these or the computer that allows the path to ground.

 

Guys, I hate to tell you this but an AOD doesn't have a lockup torque converter. An AODE does, but not an AOD.

Instead, the AOD has two input shafts. The second input shaft splines into the torque converter housing instead of the turbine thus bypassing the "fluid coupling" and driving the 3-4 clutches directly. So the effect is as if the converter has lockup when in fact there is no clutch in it.

The problem isn't that its stuck in lockup, the OD clutchs are welded together. Very common problem in an AOD and fits the symptoms described.

Steve
'95 Clubwagon XLT

 

This is correct (though some still call it locking). It was not one of Fords better ideas but I have seen a few go a lot of miles in conservative usage.

 

So even though I hear it go through all gears (at least I think I do) when manually taking it through the gears the "welded" scenario sounds like the most likely culpret? This is a new rebuild albeit from other than a regular tranny shop and has maybe 15 miles on it. It did sit for 8 months (pan side down).

 

Oooo, a recent rebuild from an unknown source? That could be ugly.

First, are you sure its a rebuild? Can you verify that?

Second, assuming it was rebuilt, its very likely that the rebuilder made a mistake or missed something that's causing the problem. Automatic transmissions are very complex devices and even experienced rebuilders make mistakes or miss something that causes much anguish to figure out.

Also, its still possible that the clutches are welded up. It can happen in 15 miles too. Incorrect throttle pressure adjustment can do that very quickly.

Steve
'95 Clubwagon XLT

 

Yeah, I know. I believe it's a rebuild for a few reasons. I've had the pan off and everything was cleaned with no residue from even the slightest use. There was also a light weight red grease on the TC snout and new seals at the pump and tailshaft. The tailshaft also had been bead blasted. But you're right, anything could still be wrong. I really thank you for your replies - I was just hoping I could get to the repairs with either a pan drop or even a TC swap.

Steve

 

The story gets better. The tranny does appear to shift manually from 1-2-3 (not OD) and when put directly into OD or D it shifts after 5 seconds (while stopped or immediately after starting) into 3rd. Yesterday, after a 50 mile drive, it started working perfectly normal - downshifts, upshifts through all gears, and OD at ~50mph. It was thouroughly warmed up by that point and a touch on the trans cooler revealed mild temps (I could still hold my hand on the supply line to the cooler). This morning it was back up to it's same old tricks. :-)

 

Old post revised...
I gave up on the stack of unknowns, yanked the problematic AOD and replaced it with another. During the teardown I noticed the following and keep in mind I can speak internal combustion but am limited in ATF. I believe the OD servo was galled and scratched as it took some real whacks to get it to move. I also had a balloning TC with the ever telling bolt marks on the forward edge from the flex plate bolts. I enjoy my correctly shifting replacement, the very cool Lokar shifter, and not pressing that bazillion pound clutch pedal anymore.