I "checked" the end play by eye but need to do as you said bigragu and use a caliper or something to really measure acurately.

On the crankshaft thrust bearing. If it was going and cause the flex plate to rub, the metal filings wouldn't end up in the fluid would it? They'd be outside the case right? Either way, I didn't see anything on the viewplate when I took it off but will check again soon.

 

I did the "check by eye" initially, too. I believe, with the fact that the movement is so minute, we have aging eyes, and that little guy in our head(his name is Inde Nial), will make for just a downright bad guess. When I was doing mine, I would relay to my father in law(retired Kenworth mechanic) "hey, Emery, it only moved like a sixteeenth, if that....I think....maybe a "hair" more"

After he heard the hair thing, he no jokingly blurted out, in a raised voice, "set the dial indicator like I said the first time. You said you have one- USE IT!! And remember, no more than .012!!!"

Well, I was at .045, and when I told him that, he said check it 3 more times. Same reading.

His final words to me, (after I pleaded "that's such a small movement, it should be okay, right?"), in a sad tone was "I don't know what to tell you, except that you'll have to drop that oil pan". Right then and there, I knew it was serious.

My point I'm trying to make is, how do you "guess with an eyeball" that small of a movement? All it would take, is for the harmonic balancer to be removed, pry the crank rearward, set the indicator on the front crank, and pry it forward.
Don't quote me on it, as I'm going off of memory, but Cummins spec is .009-.012 allowable.

In the end, I'm glad I did, cause it allowed me to not only replace the thrust bearing, but I installed all new bearings on the crank and also on the piston rods.
All those sounds we worry about went away.

 

Well my luck finally caught up with me, but then again, I was pushing it and I knew it was inevitable...

Had to haul a 16' box trailer lightly loaded (one fiberglass full size Holstein cow for milking demos but that's an entirely different story...) and the noise was much worse but would still go away when I shift to neutral and decrease when I turn off OD. On the return run it would even occasionally sound like I momentarily drove over the rumble strip and I even felt it in the steering. That was a new noise. I found I could make it happen when I let off or added more fuel. I turned the OD off, the roar lessoned, the new one went away and so I got it home and parked it. Temps never got above 180* with ambient air in the upper 60's but I had to fill up and it was off by about 2 mpg or so.

I feel like it is in the OD unit so I'll pull that first and see what I have. Then based on feedback here it looks like I'll investigate the flex plate and thrust bearing in more detail before dropping the whole unit.

Big bummer is my '77 W200 is already down right now while swapping transmissions. It lost reverse and was slipping bad in the forward gears. So my only running truck is my 1951 B3-PW which will work for firewood hauling and farm chores but nothing over the road any distance...

Good news is I got my '05 Jeep Liberty CRD back together so I at least have a 4x4 diesel to run around in.

 

Have you checked the carrier bearing at all?

 

You mean in the drive shaft? No. But I do have a new one that I was planning to swap in when I did the u-joints. I've just done the two at the rear end and so the u-joint at the transmission and carrier were next.

You think it could be as simple as that?

 

Could be.

 

Yes, the carrier bearing in the rear drive shaft. That's not typically how my luck runs but I would check it before I pulled the transfer case etc. You have to drop the driveshaft anyway. Sometimes its something relatively simple.


For example: I had an old Ford truck with a 400M motor. One day it started knocking. I thought it was a rod knocking. A more experienced friend of mine took a stethoscope to the engine accessories and found it was the 5 month old alternator making the noise. The front bearing in the alternator had failed and partially disintegrated causing the rotor to contact the stator.

 

Well, it was on the list and I have the part so I'll try that first and see. It "looked" OK when I started replacing the Us over the summer but it has maybe 75K on it too.

My luck is it would be as simple as that but only after I had redone the tranny anyway. Last year I spent considerable time and effort trying to chase down a no start on a John Deere 5065. Looked at battery, solenoid, fuses, relays, key switch, wiring, etc. Turned out to be that the PTO lever wasn't completely seated and the safety switch was activated. Very frustrating and very embarrassing...

I'll let you know what I find out.

 

Just a quick update, but nothing to report really.

Finally got all the u-joints in the rear replaced as well as the carrier bearing. Needed doing but didn't help the noise.

Over the holiday I had my daughter sit in the truck while it was on stands and put it in gear. I could hear the noise but not locate it. So I got my younger brother, with better ears, to listen. He couldn't isolate it either but he "thinks" it sounds like it is in the transfercase or front of transmission. Using a hose as a stethoscope didn't help either.

Only thing I haven't done is remove the driveshafts and listen, should have done that while I had the rear one out for u-joints...

Guess I'm back to concentrating on the flexplate and/or crankshaft thrust bearing.

 

Bummer. I was hoping it would be something simple for you. I would think something would be running hot due to friction if you lost 2 MPG.

 

One of the mods I had done on my tranny was a new OD planetary with five orbital gears. I think OEM has only four. I have greatly abused it and it still keeps going.

 

Yea, me too but not that lucky. I'm giving up and taking it to a friend with a shop today. I've got the '77 truck in my "shop" with a trans swap. My DD Corolla with a high speed miss and my Jeep KJ with the t-stat stuck open and needing a timing belt change in the next few thousand miles. I'm out numbered so doing what I rarely do and letting someone else look at it...

Boatnik- how did you learn about that OD upgrade and where did you get it?

My other frustration right now is that if it is the 518 tranny I had always hoped to be able to make a bunch of upgrades while I had it out & apart. Like new beefed up TC, pressure plate etc etc. But the Jeep t-stat costs almost $200 and to do the timing belt I'm looking at $400-600 and with Christmas coming up I just won't have any money so the trans will probably have to remain stock - but it really all depends on what is wrong, hopefully will know today. And it will probably make me look stupid and give myself a dope slap... DOH!

 

Hoping for a cheap and easy fix for you KRB.

 

Me too. Sounds like you need some Gremlin Be Gone!

 

Finally!!!

I finally got my truck back from the local tranny speed shop after 3 months. Turns out the rear bearing in the tailhousing grenaded into 4 pieces. Odd it didn't show up in the fluid or the Blackstone report. So, while it was there they completely rebuilt it, new tailhousing, new bands, shift kit, low stall converter and upgraded flex plate etc. I told him how I used the truck and he built to suit.

Good news is he had it for so long due to holidays, sickness and demand, and felt guilty so only charged me costs on all the new parts + labor. Bad news is I still had to take out a home equity loan...

Sure is nice to have the 1st gen back though. And man what a difference! Totally different truck, but I've only put a few miles on it and not hauled or hooked to anything yet. Can't wait though.

Next Wednesday I'm hauling some furniture down to my daughter 250 miles away. No weight but I'll get sustained 75mph speeds. Unless it is in a blizzard like last time and it will be sustain slow speeds in 4X4...