TH350 Problem, 3rd gear

[jakeshoe]

OK guys,
I have one that is eating me up.

TH350, fresh build, TransGo reprogramming kit, mild governor mods for higher WOT shifts.
Nothing real fancy.

It was hunting from 2-3. Would backshift to 2nd, then go to 3rd, etc..
Sometimes it would backshift and would not shift into 3rd. Hang in 2nd.
I dropped the VB smoothed the shift valve, cleaned it again, and had to hit the valve bore with a lifter bore hone to smooth up an apparent burr, it didn't travel smoothly enough.
Fixed the hunting by adjsuting modulator.

So now it shifts into 3rd fine.
But intermittently it still drops out of drive. It feels like itis slipping on first instinct but if you continue to throttle it pulls in 2nd. It is freewheeling in 3rd.
I can shift to 2nd and manually shift to 3rd and it goes back into 3rd fine and will stay.
It seems to "drop out" only when it is very warm. Like 20 minutes of driving.

Anything I'm overlooking?
don't have a pressure gauge immediately available.

Obviously it is a VB or direct clutch problem. I air checked the clutch packs on assembly though... Very careful with seal install.

What did I mess up?

 

[blackplague]

It may be in the governor circuit.

Remove the governor and measure the lands of the governor. They should measure .800 and up. If yours measures under, you may want to try another governor. Put index finger in the governor hole and make sure the governor hasn't wore grooves in the case. The last thing to try requires removing the tail housing. What you do is put the governor back in and install the cover, Then get a set of feeler gauges and stuff all the feeler gauge sizes you can except for the .010 between the governor gear and the case, when you can't get anymore in, jam the .010 in with the rest of the feeler gauges, then with a ball peen hammer, smack the center of the governor cover, Then put it back together and try it.

 

[jakeshoe]

I swapped governers once. I at first thought it was a governer problem. It MAY be.
I haven't set the lash though. Will try that. Thanks.

 

[blackplague]

When you swapped governors,did

you swap over the springs for the governor they give you in the kit? It's not that important i'm just curious.

 

[jakeshoe]

No I used the springs in the original gov. but just plugged another one in because I had a couple of thou wear.
New governor made no change to the original problem of no shift to 3rd.
found the binding shift valve, repaired, shifts good now, but had a hunting problem, seems I fixed it with a modulator adjustment.
Also thought maybe I had killed the 3rd gear dropout, but it happened once yesterday.
Feels like the directs are disengaging. I'm sure they are, but not sure if it is caused by the VB, Gov, or a sealing issue internal to the direct drum, pump rings, or what?

I may swap those springs back when I check the gov lash. Should only have a major effect on WOT shifts right?