TH400 help

[AKbigsub]

My tranny is not working right. It takes anywhere from a few seconds to a minute (or more if it is cold outside) to go into gear. It is most pronounced when I first start it up. For a while (a couple weeks) it was shifting fine after it went into gear the first time. Then last night, I apparently lost second gear
*If I leave the selector in D, it wil not shift until the RPM's are way high (I have no tach).
*If I start with the selector in 2, it will not shift out of first.
*If I am in D and going 20 mph and I manually shift to 2nd, the engine revs an the tranny disengages (it feels like a manual tranny rig feels when the clutch goes out).
Now a little background: two winters ago I swamped my rig and got water in the tranny. I dropped the pan right away and pulled ice chunks out of it. I replaced the filter and promptly had the fluid flushed. Everything was fine until about a month ago. I had the tranny flushed again and developed a small leak (so i thought) from one of the lines. On New Year's Day I went wheeling in -35 deg F cold and had a blast. Right after that the tranny started the I don't want to go into gear until the engine runs for five-ten minute thing. I checked the fluid again last night. It smelled like new fluid still (not burnt at all) but I had to put two quarts in. The shift problem is still there. I have not looked at the filter yet.

What do you all think?

 

[GsxrMike]

Sounds like it is toast! My tranny shops don't charge much for diagnosis. My local tranny shop does it for free.

 

[K5dreamer]

my th400 is doing the same thing. sorta, as far as the not going into gear for a while after startup, if i have it in drive, and rev it, it will drop into gear, it drives normally, but sometimes when i come to a stop it will be in neutral again when i try to move, i have to rev the engine for it to drop into gear again. not only that, but my mileage seems to have dropped.

from what ive looked into, it seems to be the pump, and pump seal. causing either the converter to drain empty into the transmission while its sitting, or the pump dosnt create enough line pressure to clamp down the clutches.... or both. but i am far from being a transmission technition so thats a rough guess from my limited knowledge.

 

[shaun89]

i would guess the pump also...i think theres not enough pressure in it to work correctly

 

[dyeager535]

Pretty easy to check if you can test line pressure. Hopefully you can find a place that will do it for free.

Or just bite the bullet and rebuild it yourself.

My speculation would be that it's nothing external that is affecting it. You can check the modulator, but that's shift firmness, not timing. Check for case cracks or leaks, if you are losing fluid.

 

[K5dreamer]

oddly enough i also think the previous owner overfilled the transmission, as i did have a rather bad leak that i tracked down to a loose trans pan. after retightening all the bolts, i havent had any more leak, but the trans still shows full, and there was a signifigant ammount of fluid on the undercarrage. and im pretty sure im testing it correctly, warm, in park, with the engine running. other than that, i havent detected any external leaks.

if nothing else, im looking at this as an excuse to put the 700R4 in there.