[6426yy]

TH350 This thing has been kicking my ***! It air checks fine I've went through the VB nothing, changed the governor (first one had a transgo kit in it) nothing. Second is like neutral hits everything else fine. Any ideas I'm gonna swap the VB tomorrow. This time I even changed the case and pump housing because I didn't find anything inside.

[Crosley]

Originally Posted by 6426yy

TH350 This thing has been kicking my ***! It air checks fine I've went through the VB nothing, changed the governor (first one had a transgo kit in it) nothing. Second is like neutral hits everything else fine. Any ideas I'm gonna swap the VB tomorrow. This time I even changed the case and pump housing because I didn't find anything inside.

I need clarification on operation.

In "D" the trans will move the vehicle from a full stop?

When 2nd gear shift should happen... the engine revs up ? Or is there simply no shift? Then the trans shifts to 3rd gear and drives fine down the road?

Or does the trans pull a 1 - 3 shift and skip 2nd gear completely?

[6426yy]

It will pull from a stop in drive. There is no 1-2 shift, it's not like neutral then shifts into drive fine. I have good vacuum at modulator and it is new. It's like it won't come out of first when shifted into second. My other builds have been fine, don't know why this one is fighting me so much.

[gmc1990rodder]

just wondering , probably a stupid question.... will it shift into 2nd gear if you manually come from 1st to 2nd to drive? or is it just seem to be stuck in first gear all the way?

[SSedan64]

Does a 1st to 3rd shift? Just no 2nd?

[6426yy]

manually shifting from 1st to second, stays in first, from second position to drive shifts fine.
when left in drive is stays in first and will not shift up. I think it's a modulator problem but can't figure out what. I'm gonna go check the mod real fast. maybe the diaphragm is bad even though it is new?

[6426yy]

Modulator checked good. Any ideas?

[tnsmith10]

Originally Posted by 6426yy

Modulator checked good. Any ideas?

if its shifting 1-3 and no second, id be looking into the valve body, or checkballs/location.
2 ways for 2nd gear to work, manually through the band, or in auto where it uses the intermediate clutches. if both ways are in proper order, then its going to be most likely valve body/serparator plate, or checkball/s.
its not going to be modulator related, as it in auto is shifting 1-3 from what i read. and a modulator is not going to cause a skipped shift.

[6426yy]

Thanks for the replies. There is only one check ball in it, the one by the modulator. I'll try and pull the VB off again tomorrow. Doesn't make sense.

[tnsmith10]

heres another thought... i was just talking to the old man a few days ago about these trannys and he told me that theres a difference in the separator plates on 350's between early and late. now, ive never seen a difference personally, but hey, i havent seen it all.
maybe crosley can shed some light on this???
one last thought, do you have the valve body gaskets on the correct sides of the separator plate?

[Crosley]

Originally Posted by tnsmith10

heres another thought... i was just talking to the old man a few days ago about these trannys and he told me that theres a difference in the separator plates on 350's between early and late. now, ive never seen a difference personally, but hey, i havent seen it all.
maybe crosley can shed some light on this???
one last thought, do you have the valve body gaskets on the correct sides of the separator plate?

there are a pair of holes that will create a non shift situation, actually the lack of the hole in correct location. this may be the problem here.

This would be on an OEM plate, not aftermarket.

After market plate or the proper OEM plate with current v-body gaskets solve the non shift problem. I will look for photos.

If you have the v-body off, compare gaskets to the OEM plate in the area near the accumilator hole , the large one it's near 2.250 inches in diameter. Couple of holes moved slightly in that area. they are oblong , not round

[6426yy]

Thanks guys I'll pull the VB tomorrow. It has a stock plate in it now that I drilled the 2 and 3 holes out. The first time I rebuilt this trans I used a transgo kit with the Z plate for dual feeding but I've done that internally now. Thats why I went back to the stock plate. So I don't know why it didn't work the first time around. It has to be something simple stupid like that. I'll let you know.

[6426yy]

Well I pulled the VB today and took a couple of pics. The used separator plate is the one that was most recently in it. The zinc(?) plated one is one out of a B&M kit I believe. Dual feeding the directs shouldn't mandate a aftermarket plate should it? That would defeat the purpose. Both stock plates that I have are identical so I'm not sure if there early or late.

[Crosley]

here are the areas I speak of;


Late design plate:





Early plate that can cause a 'no shift' with common gaskets used, holes are covered :

[Crosley]

Originally Posted by 6426yy

Well I pulled the VB today and took a couple of pics. The used separator plate is the one that was most recently in it. The zinc(?) plated one is one out of a B&M kit I believe. Dual feeding the directs shouldn't mandate a aftermarket plate should it? That would defeat the purpose. Both stock plates that I have are identical so I'm not sure if there early or late.

If you dual feed internal, did you plug the proper hole in the OEM plate to avoid a large internal leak while in 3rd gear?