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I've been doing some research and it seems like the internal dual feed mods are a better approach than using the HD2 kit if the trans is already apart.
My question is, what parts/steps in the HD2 kit are still useful even with the internal dual feed mods?
Is there a cheaper shift kit out there that doesn't have the parts/steps for the dual feed? I'm curious if I can sell the HD2 kit and get another kit that has just parts that I will actually use.
I'm doing a full rebuild/overhaul of the trans with Borg Warner high-energy clutches, 6 disc direct, all new solenoids, gaskets, seals, pistons, billet input shaft. Looking for it to be comfortable with 700-800rwhp.
We internally dual feed. The HD intermediate clutch snap ring is similar to what we use on our builds.
The boost valve and spring are decent.
Don't use the pressure relief parts.
Thanks Jake! Would you be able to guide me on what steps in the HD2 kit are not necessary with the internal dual feed mod? I understand that Transgo has done their homework and the kit is meant to be installed per their instructions, but if the direct clutch is dual fed internally then I'm guessing some of the steps are unnecessary or downright shouldn't be done.
Step 1: Drill the hole in the valve body between the torque signal and "void" passages. I think this is only if using the Transgo pressure relief valve.
Step 2: Install blue springs on accumulator valve for firmness.
Step 3: Remove o-ring on shift solenoid feed filter, install new tapered plug with o-ring, install filter and orange spring, install new end plug. What does this accomplish? Is the filter not supposed to have an o-ring?
Step 4/5: Drill for Transgo pressure relief valve.
Step 6: Drill the separator plate for shift firmness. Can this be done with the stock plate?
Replace 3rd gear accumulator spring with white spring.
Discard reverse check ball in the case but keep the other 7? Is this necessary with internal dual feed?
Step 7: Install new reverse boost valve and springs into pump. Is this where I would use the Sonnax boost valve instead which is self regulating and eliminates the needs for steps 1, 4, and 5?
Step 8: Install new stronger 4th bolt and washer. I read to not do this since the ID of the Transgo bolt is smaller than stock?
Step 9: Install hollow sleeve on short end of 1-2 servo pin.
Step 10: Install new orange 1-2 accumulator spring.
Step 11: Change release springs in direct clutch. I heard this is good to do.
Step 12: Install thicker intermediate snap ring. No brainer.
Step 13: Enlarge hole to prevent pump front seal blowout. Seems like this is good to do.
Step 14: Drill a 3/64 hole in the pump between the "line" passage and the converter feed passage. Does this just boost pressure to the converter? Necessary? I read the PI recommends doing this with their converters.
So I'm thinking of skipping steps 1, 4, and 5 and doing the Sonnax valve instead. Skip installing the 3-piece separator plate and using a stock or HD one instead. Skip step 8 and use the stock bolt. And do everything else?
I also heard to not remove the inner seal from the direct drum because otherwise the fluid from the 3rd gear side will centrifuge out to the reverse side, and since all of that fluid is trying to leave through the same small hole the disengagement is lazy. Any thoughts on this?
Sorry for the mass of questions. I'm hoping to get this thing built as reliably as possible, but I also want to understand why I'm doing this mods and what they accomplish. Thanks.
Step 1: Omit
2: Sure, not super critical.
3: Not necessary but not detrimental. Some early 4L80Es would have runaway line pressure, blow the end out of the filter, and hydraulic pressure could cause the shifter to be moved to reverse.
4/5: NO! Causes pressure control issues and trans may burnup. We tear down many cores with this mod, the valve is stuck causing minimal pressure and burnup.
6: Yes, drill to desired specs. Stock plate is OK as long as it's not worn.
7: Use one of the other. The issue is you won't know what line pressure is until you check it with a given setup.
8: NO! POS bolt will break and strip on disassembly. Stock is fine.
9: I don't like this mod. It reduces servo travel but can cause drag.
10: Not mandatory but OK.
11: If you are in the unit, yes, and drill a .060" bleed hole in the drum, irregardless of transbrake or not.
12: Yep
13: Not necessary. I've only ever seen 3 front seals blow out. One was on a high mileage motorhome, 2 were on a Supra we have dealt with that had an alignment issue with the Toyota-GM adapter.
14:Yes.
You're the man Jake! I appreciate the guidance. Should the reverse checkball still be removed with the internal dual feed?
What is the purpose of step 9?
The 0.060 hole is drilled in the bottom corner like of the direct drum like you show on your site? Is this to relieve pressure in the clutch faster? Is 0.060 okay to use regardless of what size holes I use in the spacer plate?
You're the man Jake! I appreciate the guidance. Should the reverse checkball still be removed with the internal dual feed?
What is the purpose of step 9?
The 0.060 hole is drilled in the bottom corner like of the direct drum like you show on your site? Is this to relieve pressure in the clutch faster? Is 0.060 okay to use regardless of what size holes I use in the spacer plate?
Thanks again!
#9 reduces servo travel. I prefer to keep plenty of band clearance to prevent dragging.
Yes, like the pics on my site. It prevents centrifugal apply.
Awesome, thanks for the explanation. My last question is do I still remove the reverse checkball if I'm doing internal dual feed? What about removing any of the other checkballs?
Transgo says to remove the reverse checkball in the VB, that's the one I'm referring to. Does removing this one accomplish the same thing as removing the one from the case?
I'm having trouble figuring out which checkball you're referring to (I think I messed up my wording and confused myself). In the 4L80E manual (the colored one, not ATSG) they show checkball #9 as the one Transgo says to remove. The manual says it's located in the case on the valve body side (along with 7 other checkballs). Looks like this check ball regulates reverse flow through the spacer plate, but doesn't have anything to do with 3rd.
And then checkball #11 is the one that's in the valve body on the case side (along with 1 other checkball) and this one is a 3-way valve between 3rd Cl, 3rd/Rev, and Rev.
From studying the circuit diagrams, I'm guessing that #11 is the one I should remove for the direct to be dual fed?
I'm having trouble figuring out which checkball you're referring to (I think I messed up my wording and confused myself). In the 4L80E manual (the colored one, not ATSG) they show checkball #9 as the one Transgo says to remove. The manual says it's located in the case on the valve body side (along with 7 other checkballs). Looks like this check ball regulates reverse flow through the spacer plate, but doesn't have anything to do with 3rd.
And then checkball #11 is the one that's in the valve body on the case side (along with 1 other checkball) and this one is a 3-way valve between 3rd Cl, 3rd/Rev, and Rev.
From studying the circuit diagrams, I'm guessing that #11 is the one I should remove for the direct to be dual fed?
Thanks again Jake!
I was tempted to let you learn this one the hard way...
Not to pick on you or single you out but, THIS is a good example why I recently quit selling parts, valve bodies, and transbrakes.
First,
I shouldn't be telling you to alter the TransGo instructions. You paid for their product and they should provide tech support to you, but when you don't follow their instructions, you are on your own.
I'm sure it's as frustrating for them, as it is for me, when people can't follow instructions, or think they can outsmart your design by modifying it.
Secondly,
You stating "in the valve body on the case side" or "in the case on the VB side" makes absolutely no sense. The checkball is either located on the case side of the plate, or in the VB. So you're adding to the confusion, for yourself and possibly others.
There are two checkballs in the VB itself on a 4L80E. There is one near the manual valve that separates manual low band apply from reverse band apply.
There is another near the 3-4 shift valve (outboard of) that separates 3rd gear direct clutch circuit from reverse direct clutch circuit.
LEAVE THESE ALONE! DO NOT ALTER OR REMOVE EITHER OF THESE CHECKBALLS.
The reverse checkball in the case can be omitted or installed, it doesn't really matter. I omit it.
As I stated before, when using a stock plate, the 3rd/Rev checkball in the VB needs to be there or you will have a massive leak in 3rd gear.
I haven't used a TransGo VB kit in years. When I last used their kits, they had you modify a stock plate. I know now they send out a sandwiched plated to dual feed.
The 3rd/Rev checkball in the VB will technically dual feed if left out, but there are other things that must be done to prevent a pressure loss in 3rd gear.
You are dual feeding by removing the seal on the direct drum and/or 2nd ring on the center support, and then plugging the reverse side of the center support. That is all, no other mods are required to complete the dual feed process. You can do this using an absolutely stock VB and plate.
You are drilling holes larger in the plate for firmer shifts.
You are omitting checkballs for firmer shifts.
You are installing a different accumulator valve spring and 3rd accum spring for firmer shifts.
You are installing a boost valve assembly for more line pressure, which gives more clutch clamping force and firmer shifts.
You are not doing their pressure relief mod because it's a problem waiting to happen.
You are not using their sandwiched plate because it has potential crossleaks and limited flow.
Thanks for bearing with me Jake, and I appreciate you not letting me make a mistake. I was taking what you are suggesting and applying it to the circuit diagrams to better understand how the dual feed process functions, not just how to do it. As an engineer I prefer to understand why I'm doing something rather than blindly following someone's advice. I believe I understand how the dual feed works now. Thanks!
Did you seriously just use your first post as a member to revive a 6 year old thread? Really?
Get outta here.
If you're internally dual feeding...don't even buy the HD2.
Just get a sonnax boost valve, drill the sep plate, and internally dual feed. That's it. Use a snap ring from a TF727 (.106 thick usually works best)
When internally modifying it to use both halves of third (high) gear, I will leave off the second ring on the center support. I do not like leaving off the center seal in the direct drum, as this can slow down the 3-2 downshift some. I like using the "peek" step cut sealing rings here in all TH400's & 4L80E's, as they work very well. The .106" snap ring for the intermediate clutch from the TF727 has always been a good idea.
When internally modifying it to use both halves of third (high) gear, I will leave off the second ring on the center support. I do not like leaving off the center seal in the direct drum, as this can slow down the 3-2 downshift some. I like using the "peek" step cut sealing rings here in all TH400's & 4L80E's, as they work very well. The .106" snap ring for the intermediate clutch from the TF727 has always been a good idea.
I have experimented over the years with the late 4L80E Peek style sealing rings and have gone back and forth between them and the solid Teflon rings.
I like how well the Peek style rings hold up especially to excessive heat.
However I really wish they would air check better...
For the pump (Currently at least) I use the smaller Peek rings on the THM400, the larger Peek rings on the 4L80E (of course), but I have been using the solid Teflon rings in both units for the center support as apposed to the Peek rings.
I prefer the original lube circuit design (THM400 and Early 4L80E) over the new lube circuit (Late 4L80E), even though I use grooved bushings in all the units regardless (Late design sun-gear shaft/ stator support tube bushings) But I do use Peek rings on the center support in units that I find are regularly run excessively hot. Especially Late 4L80E Units that run excessively hot. I also usually use a hollow main shaft in the Late 4L80E Units for improved lube as well.
For the intermediate clutch snap-ring, I like to use a very large spiro-lock instead.
Last edited by vorteciroc; 06-05-2019 at 10:27 PM.
has anything changed over the years with the recommended steps? I see I'm not drilling a couple steps which I've nice. I'm partially tearing my 4l80e down to see what's inside. was gonna do the HD2 bit then nearly got shotgun blasted into not doing it, or at least ommiting several of the steps lol
im at the blue springs step lol so nothing has been irreparably modified yet lol
im following allong thia video currently that doesnt do the pressure relief modification.
Having been down this road before myself jake's comment in post #12 rings true. either use transgo's kit or don't. if you do follow their instructions, that's what you paid for. you've been informed in other post(s) on the "modified" transgo instructions, not sure why you need to dig up a post that's almost a decade old. if you want my 2 cents: the trans is out, tear it down and dual feed it "the right way". get a sonnax boost valve and use your stock regulator spring. drill out the shift holes to quicken/firm up the shifts. you can also block 3rd or 4th accumulators, I would block 3rd accumulator myself if dual feeding. sell/return/throw out the transgo HD2 kit. Having done a few of these now and learning from some builders on this forum the transgo kit is a waste of time/money. I have used the HD2 separator plate on a few transmissions that we did not want to tear down and were trying to lengthen time between overhaul. these were STOCK applications with trans in the vehicle still. After my last adventure with an HD2 plate (manufactured wrong) I will never use the HD2 plate or kit again.
EDIT: get AFL reamed, either buy Transgo reamer and valves or find a shop thay can do it (Sonnax apparently works fine too but expensive)
08-29-2013, 01:28 PM
4L80E internal dual feed vs. Transgo HD2 
