TH350, Early shift to 3rd

[jakeshoe]

Hey guys,
WHY is it that I can build 50 trannies for anybody else and they work flawlessly.
When I build one for myself it takes forever to get it right...???


OK,
Finally got back to meesing with my '72 Camaro (anybody wanna buy it?)
Trans shifts good, firm but not too hard, etc.

I replaced the governor with a new one due to the old one having too much wear.
This thing has a TransGo Reprogramming kit by the way...
Swapped out the governors, put the TG springs in it, slapped it in, was shifting to 3rd pretty much immediately after the 1-2 shift.
I can FEEL the seperate shifts, 2nd works great manually shifting, but in auto mode it shifts to 3rd TOO quick.

I pulled the governor today, drilled a 3/8 hole in the outter weight to delay 1-2 shift slightly, then took quite a bit of material off the inner weights to get the 2-3 shift up there.

I've adjusted the modulator, kickdown cable is good, kickdown works great, shifts too soon also but everything works OK.

I have the correct TG shift valve springs in the VB, etc..
Those yellow gov springs are the heaviest I have so....

Do I need to find a stiffer 2-3 shift valve spring or ?

1-2 shift seems good, all the time, but 2-3 needs to be later at all throttle positions.

Any suggestions?

Thanks in advance!

 

[blackplague]

WHY is it that I can build 50 trannies for anybody else and they work flawlessly.
When I build one for myself it takes forever to get it right...???

Answer: the natural law of physics > anything that can go wrong, will go wrong,especially when it's yours. {happens to me all the time}.

The Trans go kit should have had you put a White spring on the 2-3 shift valve. To my recollection that spring is pretty stiff.

In the 2-3 line up, there is a valve that rides in the aluminum bushing you have to remove to get to the 2-3 sping, that valve that rides in that bushing has a little spring in the snout, it could be missing.

Did you put the gold spring on the modulator valve?

 

[jakeshoe]

I had the gold spring on but removed it, this thing is in a 72 camaro with a 454, healthy solid cam, and 2800 converter, so part throttle shifts need to be kinda late.

Pretty sure the small 2-3 spring is there. Might be worth checking though...

 

[blackplague]

What color is the stripe on the vac mod?

I'd leave the gold spring off the mod valve for sure. Is the white spring on the 2-3 valve {between the 2-3 valve in the case and the aluminum bushing}?

 

[jakeshoe]

Well,
I'll go over the history of this trans.

Got it together,
Wouldnt shift to 3rd automatically. I could manually shift it, get 3rd, and held good, but would "fall out".
I thought it was a governor problem, so slipped another gov in, same deal.
Dropped valvebody, checked 2-3 shift valve, felt a little sticky, so I recleaned the VB totally, deburred shift valve, reassembled, same problem, better but same deal, fall out of 3rd.

replaced VB with another, totally disassembled, cleaned, installed TG parts, installed.

Same deal.

Finally bought a NEW governor, as all my used ones had .001-.0015 wear.
Replaced gov. fixed my 3rd gear shifting problem.
Amazing what .001 will do.

Except now it is early.
Holds third, will manually shift great, but shifts too soon in auto.

Pulled governor, took quite a bit off the inner weights to increase 3rd part throttle shift.
Seemed to have help SLIGHTLY.
This thing would be HAPPY with a 6000 rpm WOT shift, so I'm not worried too much about taking the weights down to nubs, but they are small now and the PT shift is way early.

So in the process, it is possible i fouled up the SMALL spring on the end of the 2-3 shift control valve.
I DOUBT it, but might have to go back and check.
Kinda running out of possibilties here.

 

[chris718]

jake it sounds like governor endplay is excessive or there is bleed of of modulator downshift oil at the 2/3 shift valve sleeve.make sure with the tail shaft off and the governor cover on that the governor doesnt float more than .020 thousandths between the cover and the pin .if it does bang in the governor cover until it has the .020 and move to the 2/3 sleeve and replace it or use a spring with the same working height but more tension.

 

[jakeshoe]

Thanks Chris,
I'll check that today, if it doesn't seem to help then I'll drop the VB AGAIN