Auto trans extension (tailshaft) seal

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billr

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Wow, I was expecting everybody to advise this would be stupid to do! Only those allergic to cold/wet would understand...

The "direct" parts, that are probably bad, are way in the rear of the case, correct? Will I have to remove the VB, shift shaft, and stuff under the VB; or will the clutches/drums slip out through the bands once I remove the pump? What about the change to a "mechanical diode" in place of a sprag clutch; is there any "gotcha" there? Does the extension need to come off? Obviously, I would be keeping my eyes closed to all but the fatal problems in there; there is no intent to make this a "rebuild". BP, if you were doing this, would swapping out the bad parts be just a 2 hour job? (I would have to re-assemble the "bad" one enough to qualify as a core.)

PS: I watched a couple of videos on 4R70W tear-down last night, I see there are no special tools or tough procedures; just a lot of parts to keep track of.
 
JackC

JackC

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Bill: I have big channel locks and big C clamp if you need them.

Or course since I have seen your shop I am sure you have both.
 
bp042665

bp042665

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2 to 3 hours job and yes vb has to come off to get to the snap rings for reverse servo and over drive servo also when putting back together you have to install over drive band servo after the band to hold into place
 
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billr

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I am in dire need of help now!

I elected to get another trans from the JY, and managed to do that just before the rain started; I mean it began raining hard as we drove away from the yard.

We started it and it moved in R enough to get it out of the garage, but no forward gears. My Snappy brick shows that the range switch is giving correct signal to PCM, but the "gear commanded" is flaky, doesn't correspond to what I would expect.

There are lots of codes now, so lets wade through that: (definitions are from our Trouble Code link above)
P1000 "OBD2 monitor not ready" I think this is normal, since the battery has been disconnected for several days
P1288 "Cylinder head temp out of self-test range" I think this was there before, and see no way it would prevent trans operation
P1127 "Front O2 sensor connectors swapped" I'm don't understand what this means, I wouldn't think the cables could reach for a swap, and expect whatever it is would not prevent trans operation anyway
P1746 "LP solenoid low conditions"
P0713 "Trans fluid temp intermittent"
P0743 "TCC solenoid"
P0750 "Shift solenoid A malfunction"
P0755 "Shift solenoid B malfunction"

Obviously, a whole bunch of trans "electrical" codes, so I checked that the main harness connector is tight, seated properly. This is the same harness that was in the truck before, not one from JY.

The harness did, however, have a spot where it had contacted a hot manifold, one wire had insulation melted away and many strands broken. That has been fixed, but I didn't repair it personally. Regardless of the repair quality, I wouldn't expect that one wire to cause so many (new) problems.

The fluid level is probably low. Again, I wouldn't expect that to cause all these codes, and am reluctant to fill it any more since it seems likely the pan/VB are going to have to come off. That is the only thing I can think to try right now; swap the VB for the one in the old trans.

Any trouble-shooting tree or schematic showing what I can be testing for regarding the solenoids and such would be appreciated.

PS: This trans, the only one that had the right combination of bell-housing, VSS/OSS, and MY that we could find, already had the pan off. There was no apparent damage to the VB or indication it had been removed (and nobody would bother to put back a VB in a JY anyway), so we took a chance with it.
 
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billr

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Found connector pin-out and solenoid resistances on the Sonnax website, checking those now...
 
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billr

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Oh my, all circuits were open-circuit when tested at the trans connector. So we dropped the pan. Lo and behold! All the solenoids are missing. That's why the pan was off in the JY. I guess we were in too much of a hurry when inspecting and putting a pan back on it. I'm thinking that missing all the solenoids could account for the present problems...

PS: Just for added fun, this bell-housing has some tapped holes that are M10-1.5 (about 17 pitch) and some that are 3/8"-16. The heads on both types of screws are reduced, 13mm on the M10 and 1/2" on the 3/8", so a 13mm wrench fits easily on both; no hints there. Luckily my son felt that the M10 wasn't going into the 3/8" hole quite right before the threads in the bell-housing got damaged.
 
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billr

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It is on the road and codes are gone. I hope to post an "epilogue" to this sad tale tonight, by which time it should have about 200 miles on it.
 
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