[chuckies76ta]

Hi: Looking at advise to upgrade a TH400 for fully automatic mode to improve shift and some performance with a Trans go kit.
Looking for a part number for kit that works well with a dual feed direct drum.


Thanks
Charles

[Half-Inch Stud]

Transgo th400 shift kit, go for Level 2 program,

Budo not do the 1st gear shift valve mod option; too dangerous and no reason to select 1st at any speed.

[zippy]

400 1-2 is a great one. The 400-3 is full manual, which I had in my last trans. Gov removed. Just put together my own diy version of the 400 1-2 kit and it seems to work well. Trans needs disassembly to take some seals out of the intermediate drum tho

[KEN CROCIE]

No question--level 2. I have level 2 in my GTO, 81 3/4 ton pu, 72 Riviera

[chuckies76ta]

Originally Posted by zippy

400 1-2 is a great one. The 400-3 is full manual, which I had in my last trans. Gov removed. Just put together my own diy version of the 400 1-2 kit and it seems to work well. Trans needs disassembly to take some seals out of the intermediate drum tho

Did you mean seal in the direct drum for dual feed, and second sealing ring on intermediate .. Thanks

[chuckies76ta]

Thanks Guys. The 1-2 kit is the go to. Kit 3 is no automatic as mentioned so that's no good. What about the Go Pro? I've also read somewhere that the dual feed mod done doesn't play well with the kits, as the 3rd clutch dual feed separator plate to achieve same results. Thoughts?

[zippy]

Originally Posted by chuckies76ta

Did you mean seal in the direct drum for dual feed, and second sealing ring on intermediate .. Thanks

Yes, Left off the 2 seals 1 on the drum, the other on the center support.

Last 400, was similar to the 400-3 kit. Full manual, with dual feed separator plate. Old kit tho, separator plate is only 1 plate. I've read transgos kits now have multilayer plate.. This trans I made my own manual/auto with internal dual feed. It performs exactly the same as my manual kitted one. Except retaining the Gov and auto mode. Not sure how I like the auto mode LOL. It's been almost 20 years of driving her Full Manual.

To convert from Manual/auto to full manual is an easy VB mod. Plug Gov tube holes and drill a 1/2 bleed hole in passage to bleed the gov feed pressure. Lots of youtube help on that

[chiphead]

The Pro kit is the most comprehensive street or strip kit. It retains automatic shifting and dual-feeds the direct clutch using a multi layer separator plate that routes fluid to both sides of the direct clutch. It also comes with a replacement 2-3 accum piston, shift valve springs, accumulator springs, a PR spring and a few other goodies.

This is the one I used on my TH400. It replaced a slam-bam TCI kit. I think it will work with an internally dual-fed unit, assuming the reverse feed near the center support bolt was plugged.

You can also re-use your existing separator plate if you're internally dual fed, but use the TG shift valve springs. Mind the recommended feed hole sizing on your separator plate. Large feed holes and 160-180 line pressure will really shift hard. You can also use the accumulator springs in the TG kit, to impact 1-2 shift feel. Use the balls like the TG kit recommends.

I blocked the 2-3 accumulator, used the mid-range 1-2 accumulator springs. I drilled the 1-2 and 2-3 feed holes to .120". With a TSR PR spring, its got pretty quick shifts but not harsh. You may want to try .095-.110 on the feed holes if you block the accum and raise line pressure to 170-180PSI.

Compare the feed holes, accumulator holes and 3-2 downshift holes between what you have and the TG plate. You'll see critical differences. You get into trouble when you mix home brew mods with actual shift kits.

https://tsr-racing.com/th400-heavy-d...ef-spring.html

If you buy a dual-feed kit and don't use the plate, I'll buy it from you. I think 120 is a bit on the aggressive side, I should have gone smaller on the 1-2 hole. Hitting the 2nd gear sprag too hard at WOT is a bad thing.

[chuckies76ta]

Well, I decided to grab the 1&2 kit. It says it does 3rd clutch dual feed separate plate. I've never done a full automatic tranny. The tranny I want to use, I built with a Hughes full reverse manual valve body. That was an easy upgrade as that's what we have always used. I already have the direct drum and Intermediate sealing ring removed to dual feed 3rd gear. It is rated for around 1000 hp with the mods I did. I also used the 4L80 direct drum with 34 element sprag. I also did some upgrades to rollerized it. Did new 1st gear drum. New pistons and center support and thick snap ring. Also has a JW bell housing on it. Upgraded to five clutches and steels. Four pack steels and clutches for 2nd gear. I'll have to take it apart and install the automatic pieces. Oh, the pump is already done with the higher pump spring, and tapped and drilled for .125 orifice converter feed.

[chiphead]

I don't know how much HP you're making, but Jakeshoe had some thoughts about the TG kit and high HP. He recommended doing the internal dual-feed instead of the TG dual feed plate over 600HP. He claims the TG plate dual feed is too slow for applications that need a very fast 3rd gear apply to keep from burning the clutches. He did say you don't need more than 185 PSI line pressure up to 850 HP or so.

When you say Intermediate sealing ring, you mean the correct seal ring on the center support, correct? See below thread.

"unknown member" is Jakeshoe, I guess he deleted his account


https://www.chevelles.com/threads/in...-th400.185541/

[chuckies76ta]

When you say Intermediate sealing ring, you mean the correct seal ring on the center support, correct? The kit will be here next week and I'll try to figure out what needs to be done. Ya, I've read lots of post on Jakeshoe.

Yes, second sealing ring. Thank you Chiphead for all your time and help.