If you think you found the problem, yoke's on u!

One thing I can't be accused of lately is having a surplus of free time.  I mean, I guess someone could make that assertion, but no way in hell would it hold up in court.  That's why my updates have fallen in the band of "infrequent to rara enough to start assuming the project went dead".  My odd jobs have consumed far much more of my time than I think anyone could reasonably assume, and Eagle has become very cranky as this never-ending winter continues to grind down on this god-forsaken territory.  These factors combined have slowed my progress on the Gremlin to the pace of a snail on barbiturates.  Despite this, I still have some news to report.

The last few days have been spent by my friend and I investigating and attempting to remedy the cause behind a 1978 F150 with a 4.9L I6 being unable to hold idle.  I'll bet I'm not giving anything away by saying that it was determined to be caused by the Carter YF that it came equipped with.  After a rebuild and attempted tune, idle is now maintained on both circuits, though low RPM is accompanied by loss of vacuum, making the slow idle circuit require a much higher RPM than is advisable.  Consequently, we may have further work ahead of us in the form of installation of a new manifold gasket.

I've also managed to install the Gremlin's flexplate, though my clearance situation demands an open-ended torque wrench.  I'm hoping to find a clever solution that doesn't hinge on spending more money, but I'm not sure that's in the cards. 

Speaking of things around the transmission and clever solutions, I came across this video that would've been a godsend when I was pulling the trans and will be a huge help when I finally get it bolted back up.  The video covers taking care of those damn top three bell bolts, and the access via the firewall is the same for my '78 Gremlin with AC (not a big surprise there).  Really handy info- check it out here:

    https://youtu.be/Hf3usGA0-78

While Gremlin sits neglected, Eagle is still playing little brother.  Recent developments and persistent behaviors have steered my attention with it towards it's flexplate, but I'm getting ahead of myself.

If I didn't mention it, the problem that prompted me to do the trans fluid change was a resonant groan that would come from. . . somewhere when I was moving uphill under load, accompanied by a lack of power.  If I didn't let off the gas, this would be followed by a hard shudder.  The fluid change had no real effect, and the behavior was intermittent.  Since I usually drive with my window rolled down, it began to sound like it stemmed from the front left wheel.

I checked the torque on the spindle/axle nuts on all four wheels and found that the suspect wheel was slightly below spec.  The issue persisted.

I thought that it could be the slip yoke, so I greased the hell out of it.  No change.

I had some u joints that fit, and Eagle was overdue for a change, so I got that settled.  It made zero difference.

I should mention at this point that the knock I was hoping had been coming from the AC compressor returned.  This is important because I found a video that featured a 4.0L Jeep demonstrating a condition that I had previously never heard of: torque converter to flexplate knock.  Suddenly, all of the problems I thought previously to be unrelated, the bad radiator, the knock, and the slug groan could all explain a cascading failure.  If a torque converter is cooking and ballooning because of a failing radiator, it could make the flexplate to crack, or at least work the bolts loose.

Tomorrow I'll be pulling the inspection cover and counting my blessings that the cat is still pulled to aid in other troubleshooting efforts.  Reason being is the small switched exhaust pipe that runs right in the way of the inspection area won't be an issue.  As an aside, it's pretty irritating that this piping is run like that and the service manuals say jack all about how you're supposed to deal with it in a stock configuration.

Regardless, here's hoping that the lack of usual symptoms of a failing torque converter means that I just have to tighten the bolts that attach it to the flexplate. . .  Good god, do I hope that's all that I need to do.