Transmission question

[IowaTom]

Guys - I was running an errand this morning and on my way home, tried to downshift from fourth to third and it wouldn't go in.  !!!  Pulled over to the shoulder, tried 2nd and it went in fine.  Still no third gear, so shifting from 2nd to 4th just to get home.  Once in the garage, tried "granny" first; nuttin'!  I've determined I have 2nd, 4th and reverse.  

What the heck... Why all at once with no warning did my tranny break, you suppose?  Wasn't hauling or pulling anything.

I'd bet having a transfer case makes it more complicated to remove, right?  Oh well, it always something.  :-)

[81-F150-Explorer]

Sounds like a shifting fork problem to me.

What tranny do you have? T-18?

[IowaTom]

I'll go out and get under it!  Stay tuned!

[IowaTom]

I couldn't find anything but "C" and a line of numbers.  I know BW tranny's clearly mark their T designations on the older ones, but maybe you fellers would know what this monster is.  

[FuzzFace2]

Well it is 1 of 2 transmissions T18 or NP435

Before pulling the trans I would pull the top cover to give a look see as it could be a shift fork.
Just make sure the trans is in neutral before pulling the stick or cover off the trans.
Dave ----

[IowaTom]

Thanks, Dave, I'll do that and report back!

[IowaTom]

I'm assuming I remove the bolts around the perimeter of the tranny's top?
Nice that I'm able to get to it as easily as I can!

[IowaTom]

Sorry...this angle is better.

[IowaTom]

Turns out, it's a NP435.
I pulled the top cover and shortly noticed a spring that seems to have popped out of a synchro and the synchro itself is very wiggly.
The shift yokes are fine and even the plastic inserts are still there.
Ugh!  I'm probably going to have to drop the trans for the fix.  Mine would be a 4X4.  Any clues on how to get it out?
Thanks Guys!

[Gary Lewis]

I don't remember the shift pattern on the NP435, but I'm guessing that the problem is just the shift linkage rather than internal to the transmission.

There's a diagnosis section in the General Manual Transmission Service document, which you can find at Documentation/Driveline/Transmissions/Manual Transmissions/General Manual Transmission Service.  And there's instructions on how to remove the transmission in the page at Documentation/Driveline/Transmissions/Manual Transmissions/NP435.

[IowaTom]

Thank you, Gary!  That'll be SO helpful.  I'll do my homework!

[Gary Lewis]

Good luck, Tom!  

[IowaTom]

Gary - I'm beginning to think you're first guess is correct.  My first gear shaft won't go through the detents.  Tried using a screwdriver to force it, but she's stuck.  The larger yoke moves okay but the reverse pawl also feels stuck.



Thinking I'm going to have to get this plug out -



Wonder what would keep this slider from moving, unless something's broken in two within.

[Gary Lewis]

Have you tried pulling the driveshaft and turning the engine a bit?  Sometimes things get in a bind and you can't shift w/o relieving the bind.

[IowaTom]

Well, since the trouble began while driving, I kinda think something broke, snapped or unsprung.  I can get two of the three shafts to slide and I'm thinking whatever's behind that plug might be the root cause of my shift troubles.

Hoping to take the top to a mechanic friend tomorrow for his opinion and will report back.  Thanks again!

[Gary Lewis]