TH350 question....low fluid probably?

[Brian Lohnes]

Dudes,

Buford is official among the living again. Cruised the car with the basement TH350 in it this afternoon. All is good as far as shifting through the gears 1-2-3. One thing that it is doing though is that when cruising at light throttle, the trans will upshift from third to second and not back down into third unless I click it into neutral and shift it back into 3rd.

The dipstick does read a little low, so I need to glug some more fluid into it, was just wondering if this is a symptom of a fluid level issue or maybe something else (vacuum modulator adjustment?). I DO NOT have the kick down cable hooked up to the carb linkage at this point, FYI.

Brian

[andy30thz]

AWESOME!! Glad to hear its making tracks again!

I've never run into this exact problem....but I have had a vacuum modulator with leaky diaphragm that made for some wacky shifts. Throw a vacuum pump on it and see if it holds vacuum.

Also, I'm not sure how the governor weights are set up on a TH350...is there a possibility something is not quite right there after sitting all this time?

Did you have a shift kit in this thing? Is your linkage adjusted correctly? I'm assuming the 700R4 column shifter works ok with the TH350?

Unfortunately unless the trans juice is pretty low, I doubt that's the problem.... I HOPE I'm wrong!!

[Brian Lohnes]

Andy, it literally does make tracks, too. Burnouts were tested and successfully completed.

[tardis454]

I had a used TH350 that did that on my 78 Impala.
The valve body & governor were varnished up from sitting.
I dumped a bottle of Lubegard in it & woke it up.



Worked perfect for 4 yrs after that.

[Brian Lohnes]

I will give that bottle of magic potion a shot!

I could pop the governor out and clean it up some, too.

[oldsman71]

second on the varnish/crude!!! that bottle of stuff should help, i unearthed a 20 year old t350 and it did some crazy stuff
but after a while and some trans x it worked ok.... and still works

[squirrel]

One thing that it is doing though is that when cruising at light throttle, the trans will upshift from third to second and not back down into third unless I click it into neutral and shift it back into 3rd.

2-3 is an upshift, going from 3 to 2 is a downshift. You'd think a guy who runs a site called "bangshift" would know that! ;)

How low is "a little low"? It needs to be down about two quarts (so you almost can't see it on the dipstick) before it acts up.

fwiw, every used TH350 I've taken apart needed to have something in it replaced. So don't feel bad if it has a serious problem, although I hope it's just sticky valves...

[Brian Lohnes]

Good catch Jim....jeez, that was a bad one! I am hoping it is just sticky stuff, too. The trans was fine when it was parked (15 years ago!) so hopefully it will free up and be OK, but if it isn't I understand that a 15 year hibernation can have some ill effects!

[Deaf Bob]

I've used Trans X in alotta weakish trannies before derbying them... Woke them up..
Whatever you use.. Change the fluid after some miles to get whatever gets cleared off... And add more in with the fresh fluid..
Old Buicks (50's) woke up with a huge bottle of cheap after shave added... Could tell by the smell when it warmed up..

[Barry Donovan]

I recently used a miracle goop. not into them at all.

after cleaning up what you got to, try a few tablespoons of the at 205 reseal.
if you have nitrile crap for seals, it will let you know.(those have got to go today more than ever) Else, it even forces waters out..stuff you did not know was in there.

I recovered an impossible power steering... it forced a change of 1 seal. very bad sucker side seal.

[TheSilverBuick]

How many quarts did you pouring into it, plus torque converter?

[Caveman Tony]

andy, it literally does make tracks, too. Burnouts were tested and successfully completed.

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[Caveman Tony]

andy, it literally does make tracks, too. Burnouts were tested and successfully completed.

t h r e a d

[Caveman Tony]

Andy, it literally does make tracks, too. Burnouts were tested and successfully completed.

Is

[Caveman Tony]

Andy, it literally does make tracks, too. Burnouts were tested and successfully completed.

Useless