Th350 lost all gears

Discussion in 'The "Juice Box"' started by Moral Decay, May 27, 2017.

  1. Moral Decay

    Moral Decay Member

    So I was driving out to my shop to work on my 64 special and I think my C10 got jealous and decided to give up, well the tranny did.

    I was behind a few other cars that slowed so the lead car could make the slowest turn eveeer. As traffic resumed a half sane speed I gave the truck a little gas and started to move forward, as I started going it acted like it slipped out of gear, the engine revved high like it was in neutral, so I let off the throttle and reapplied it once the room lowered again, same thing happened except I kept a steady Rpm on the engine, the tranny keep grabbing then releasing. Did that cycle constantly before I found a spot to pull off. I put the truck in park, then reverse ( backed up ok but I was backing down a slight hill) put it back in drive, started out (I was .5 miles from shop so I was hoping to limp there) I had just a little acceleration then it was gone, I pulled off again and now i had nothing but park, no reverse, 1st, 2nd or drive. There was no noises, no grand finale, just gone. I have a Hurst ratchet shifter in it so I racheted to each gear, nothing. I shut it off and crawled under making sure each ratchet position was actually moving the manual shift rod which it was so got her towed.
    I am just curious if the symptoms point to pump or converter. I know converter was replaced not long before I got it but it was a reman. I yanked it out, got it apart except pump. Some metal in filter. But everything inside looked solid. I plan on rebuilding the pump either way but is there sure fire symptoms that point to pump or converter? I just don't wanna go through all this and put a bad converter back on, but also don't wanna replace it for nothing.. sorry for the long windedness I just wanted the situation and all that happened to be clear. Thanks guys!!
     
  2. BRUCE ROE

    BRUCE ROE Well-Known Member

    It could be a failed torque converter, I've had a couple. Apparently the turbine
    gets unconnected from the shaft. good luck, Bruce Roe
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I would think to diagnose this properly, you would need to do some pressure tests. I don't think most torque converter failures result in complete loss of drive so I would lean towards something else.
     
  4. 64 skylark mike

    64 skylark mike Well-Known Member

    I had a similar problem in my '64 Skylark last summer. I had just installed a sbb 350 and th350 only 200 miles before that. I had installed a new torque converter, seals and anything else short of a rebuild. Pulled trans and took it to a shop. When he took it apart he found the pump gear had stripped off both keys that engaged the torque converter.
    He had told me to pull the cooler lines from the radiator and start it briefly and see if it was pumping, but I had already pulled the trans. That will at least tell you if the pump went out.

    He figured that most likely I didn't get the converter engaged completely during install, a common cause of my situation.
     
  5. Moral Decay

    Moral Decay Member

    Thanks Mike! Ill keep that trick about checking the pump in mind if I come across this again, I also had the trans out pretty quick after so I couldn't check much. They keys look to be intact, but I will get a closer look when I tear down the pump.
    I've heard about not having the torque converter seated properly and it tearing the pump up, I will find out soon if that was the case.
    Seems like something that would happen quick if it were my problem but I drove the truck 3 hours home when I bought it and light almost daily driving since OCT.
    Thanks again!
     
  6. 64 skylark mike

    64 skylark mike Well-Known Member

    KIMG0039.jpg KIMG0040.jpg Mine didn't go out right away either, but I had only put 200 miles on it when it did go. Of course some of those miles were a bit aggressive :D. After driving the car for 4-1/2 years with a tired 300, couldn't help getting on it with the extra power in the 350. Here's pics of the pump gear. Sorry they are so big.
     

    Attached Files:

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  7. Moral Decay

    Moral Decay Member

    oh damn, those are stripped! both of the ears on my pump gear were intact and not damaged that I could see. throughout the entire rebuilding process I found no real damage. I did find something missing, inside the intermediate roller clutch (springy one with large bearings that can fall out if you are not careful) the inner metal ring that is grooved to lock that assembly was missing entirely. I had a box of several other 350's that cases were damaged but I saved parts so I had a replacement. the only thing I found that was bad was the gasket the last person put on was done poorly
    there was def metal in the filter but what worries me most is how blocked the filter holes were.
    Any who I reinstalled everything after I rebuilt it (including the same torque converter) problem was not fixed so I ordered a new TC and should be here WED for me to try that.
     
  8. Moral Decay

    Moral Decay Member

    I got to thinking while I was sitting here looking at this thing do nothing I could try pulling the lines while it was running to see if it is pumping fluid. No fluid... In either line. Does that absolutely mean bad pump? Or would a bad tc not engage the pump? The tc looked ok on the end and the gears in the pump spun fine, and had both teeth that connect to tc.. I didn't find any major issues in the pump when I had it apart. Got me wondering now..
     
  9. Moral Decay

    Moral Decay Member

    Also, i read somewhere low fluid could cause lines to not have anything in them. I check fluid before I started it, just cause lol. And then started it and checked it running, readings were identical, I'm used to it at least seeming splashed around looking when I check it running, never really moved. It was at the top showing full the entire time without any really change after multiple checks.
     
  10. 64 skylark mike

    64 skylark mike Well-Known Member

    Hmm. I don't know a whole lot about these transmissions, I just remember the tech told me if I didn't get fluid out of the lines while running, it was not pumping. I understood him to mean it would most likely be the pump gear or the pump died. Hopefully some of the gurus on here will chime in.
     
  11. BRUCE ROE

    BRUCE ROE Well-Known Member

    The trans has pressure ports; zero pressure means the pump isn't functioning. I think
    broken pumps are caused by improper trans building or installation. Bruce Roe
     
  12. Moral Decay

    Moral Decay Member

    Took the pump back out and took it apart again, no real signs I noticed of wear but I have a parts box of 350 parts so I replaced pump gears, reinstalled pump, put new TC on and filled her up. Problem solved, tranny shifts a lot easier than before to so all is well thanks guys for all the info and tips it was a big help!
     
  13. 64 skylark mike

    64 skylark mike Well-Known Member

    Glad to hear you got it going again!
     
  14. BRUCE ROE

    BRUCE ROE Well-Known Member

    So, the pump was OK, it was the torque converter? Bruce Roe
     

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