AW4 slipping, overheating. Pump/Torque Converter troubleshooting

[driveslowsnackoften]

Or I guess more likely at this point is the pump is blown.

[Dzimm]

3 hours ago, driveslowsnackoften said:

I used the opportunity to thoroughly test this and for a minute thought it was going to be the solution but climbing back up to the house it eventually started slipped again.

If it slipped at all with the TCU unplugged you can now focus entirely on mechanical things. 

[driveslowsnackoften]

I'm guessing next thing I need to do is drop the pan and have a look at the internals, filter, solenoids and such. In the meantime, I did just jump on the other AW4 I found, on account of it be close and if I do end up needing one I don't want to have to scramble.

Not sure if it's worth the price, but I'm sure I'm going to learn a ton for having a second one I can tear apart. It's said to have 168k on it (compared to 238k on mine) and was dropped by the PPO (not who I bought it from) for an AX15 conversion that never was completed. I bought it from the new owner who's finishing the conversion.

So... as I'm cleaning and inspecting that I'm going to keep digging into my current AW4 to see if there is any glimmer of hope for it. Below is a recording I was finally able to make now that power steering is fixed. One of the recording sounds more metallic than it is in reality. I'm going to try draining the fluid today to recheck for metal flakes. My rather uneducated guess is that sound is the pump, which is why I'm not getting proper cooling.

transwhine1.mp3 transwhine2.mp3

[driveslowsnackoften]

I've got most of tomorrow off so I'm planning to drop my pan and have a look see. In the meantime I've cleaned the worst of the crud off the 'new' AW4 and pulled it's pan off. Nothing seemed immediately amiss, didn't smell burnt, no metal flakes, pan and magnets didn't look too different from what I've seen in other pictures.

Some of that even looks red

 

Note the finger wipe on the filter

 

 

MMmm, forbidden transmission chocolate.

 

Will post an update tomorrow on what mine looks like but this one I'm calling backup plan...

[driveslowsnackoften]

On 3/20/2021 at 4:29 PM, cruiser54 said:

Okay. How does the fluid look now?

 

Does your Power/Comfort switch light up when switched to Power? Is the "trans" fuse in the fusebox good?

I also checked the trans fuse just in case. It's fine.

[driveslowsnackoften]

Alright, dropped the pan on the truck and immediately the filter jumps out as looking clogged compared to 'backup plan'.

 

 

And I guess one of the previous owners hated magnets because those have been removed. And unfortunately this time I did see 'star dust' metal flake. Not sure if I missed it last time (it is much sunnier now) or if its because I overheated it again on Saturday.

 

 

 

Not sure where to go from here, I've got a new filter and gasket but it seems like the overheating could have damaged either the pump or torque converter. I think the pump can be inspected without a complete teardown but don't think TC can be inspected at all. This sound about right? Anyone want to weigh in on the audio I posted before? If the pump does go out will it make noise?

[driveslowsnackoften]

I changed the filter and installed a temp sensor (what a pain) and sadly it's still overheating. Did a repeat of last weekends drive and it failed about the same point. What's worse is because the dual radiator system or what ever its called it's overheating the entire engine. Really bummed about this, what a stupid mistake to make and potentially (likely?) kill my transmission.

[cruiser54]

I'm not comfortable with your TV cable adjustment. With the gas pedal fully depressed, see if there is any slack in that cable.

[driveslowsnackoften]

Doesn't seem to have any slack and there is no discernible difference in cable tension between no gas and full gas.

 

Another thing I forgot to note, while it did still unfortunately overheat the filter replacement did seem to address sluggish shifting.... until it overheated.

[driveslowsnackoften]

Did a bunch of reading up on the cooling system in general last night and some things of note.

 

First, I reread my manual and found I have not been filling the pressure tank to the right level, just under what it should be but possibly enough low to cause problems. Doh! This is my first closed system radiator.

 

Second, reading some threads on here one thing stuck out. I've heard a gurgling noise after shutting the truck off that seems to indicate air in the system, possibly from either running low or a leak in the system.

 

So as the truck seems to be doing fine until it inevitably overheats I'm going to start focusing on cooling system. Just idly poking around yesterday the large hose running from the engine block to the radiator (towards the left) leaked a bit if I wiggled it around. Not sure if that is high or low pressure (<sucking air) side but assume if it's leaking other parts could be too. As a start I'm going do a flush and fill. I've got a vacuum pump to degas but not sure were to do that from, the pressure tank seems to be the top so unless suggested otherwise I'll pull from there.

[driveslowsnackoften]

More poking, more testing. Went over the cooling system pretty thoroughly and it appears everything is in order. I'm not getting bubbles in the pressure tank (head gasket/exhaust leakage), and while the color isn't perfect, it's green. No chunky bits or 'milkshake' as I've heard it described for a head gasket issues. Despite this it happily climbs up to 200F, 220F with moderate hills and broke ~230F with a sustained hill and I quite pushing it at that point.

 

On a positive note when the transmission temp read 220F and falling at idle, the upper radiator hose held at 165F with an IR thermometer. I think this supports the idea that the cooling system is in fact working, but the transmission will overheat them both if allowed to.