TH350 tricks and tips

[turbobitt]

Anybody have any advise for a TH350 rebuild I'll be doing for a buddy. I am looking for making this shift hard for show and would like to know what holes in the seperator plate should be drilled and if there are any benifits to leaving any of the check balls out.
Thanks
Allan G.

 

[jakeshoe]

Best advice is don't make it shift to 2nd too hard....

Tips here:
You'll see which holes to drill. I use all the stock checkballs.

TH350 Rebuild Tech

 

[turbobitt]

Best advice is don't make it shift to 2nd too hard....

Tips here:
You'll see which holes to drill. I use all the stock checkballs.

TH350 Rebuild Tech

Thanks Jake,
I found this on a search and was very informative. The Transgo plate that I have was a little smaller on at least one of the holes. I was wondering if I should do anything to block the accumulators or something. The reson that I was asking about the checkballs is that some shift kits ommit a tleast two and I don't have a case in front of me to trace out the fluid paths. Why are some left out ? Some of them look to have an orfice near the ball to control flow. I'm assuming that maybe its for softer engagement into the foward clutchpack or reverse.
Allan G.

 

[GNeric]

I drill the same holes that Jake does out to 3/16" and the one hole I have circled at the bottom of his pic, (reverse feed) I block off for dual feeding the directs instead of blocking the hole in the case at the pump facing. I also remove the center sealing ring on the stator. Jake is absolutely correct about shifting too hard into 2nd. Lots of my customers want the neck snapping shift and I won't warranty that with stock components in there. Not good to have it shift that hard anyway.

I also use the later model 4L60 low one-way roller as there is more surface area of the rollers compared to the TH350 roller assembly.

 

[jakeshoe]

IME,
3/16 is too big for the 1-2 feed, it kills the sprag, even with a hardened sprag race.

You could make the 2-3 feed as big as you want and block the accumulator and there's nothing to break on the 2-3 shift but it will cause issues if you do 3-2 downshifts.

 

[turbobitt]

Guys,

Thanks for the input. Blocking the hole circled on the bottom makes sense for dual feeding since one of the TransGo plates with dual feeding doesn't have it drilled.

 

[GNeric]

I use the factory "LT-1" orange spring in the 1-2 accumulator with a 1/8" shim in the piston side and never killed a sprag. Only had one outer race shatter into about 60,000 pieces and told that guy it would do that. Mine still don't shift that hard. Just as fast as possible. I know too many people who want the tires to bark in their 15mph shift. Things don't last too long that way. Plus, the police love to pull people over for stuff like that.

 

[GNeric]

And now that I have mentioned this...every one that I build from now on will probably break.

 

[jakeshoe]

I don't drill them over .135" for the 2nd feed ever, even on the trans where I build the 36 element drums.

No reason to do so, and I keep the 1-2 accumulator in play as well as all the checkballs.

My build is proven to over 660 ft/lbs for over 2 years, raced almost weekly.

No reason to make them shift killer hard, crisp is all you are after, no hard parts breakage and no friction failures.

 

[jakeshoe]

I block the hole in the plate on some builds, it doesn't matter how you do it, as long as you do it so drive oil doesn't piss out the manual valve in 3rd.

 

[dr_frankenstein]

I know too many people who want the tires to bark in their 15mph shift. Things don't last too long that way. Plus, the police love to pull people over for stuff like that.

Picking on me again?

LMAO!

A.j.

 

[matt69olds]

I block the hole in the plate on some builds, it doesn't matter how you do it, as long as you do it so drive oil doesn't piss out the manual valve in 3rd.

Can you explain further? Ive had trouble in the past with direct clutches sometimes having hot spots. Could this be the cause Ive been trying to find? Ive tried tighter/looser cluthch clearace, heavier P/R springs, disabling accumulators with little success. BTW, I always daul-feed 3rd. Thanks!

 

[GNeric]

If I am, I didn't realize it. Didn't realize you "like it hard" since I am not into that.

Picking on me again?

LMAO!

A.j.

 

[chris718]

Best way to dual feed is block the reverse feed hole in the case below the pump and leave out the center seal on the drum and pump cover.Block the 3rd acc hole bore under the 2/3 acc piston with 3/8 cup plug.

 

[WINDMILL]

350 trans

I just a a 350 turbo trans go bad.... have no took it out yet to see what happen,, but slips bad in 2nd gear...

You guys keep adding to this.... might help me out, especially the guy going to build this trans back...... give me some more tips,,,,,,,,,,,,thanks guys

 

[jon86]

350 build

buy a superior th350 hp shift kit it will do the job up to 550 hp street strip all day

 

[jakeshoe]

No need to buy a valve body kit for the TH350, the mods are already covered here and proven to over 600 RWHP/TQ.

 

[j-6]

350

I just put mine in last week man its a HOSS