lt170chevelle

iTrader: (2)

Can i positeively benefit from enlarging the 3-4 feed holes on the input shaft ? Im having to rebuild a previously rebuilt trans that the warranty was not honored and looking to totally get rid of this reoccuring 3-4 clutch loss.
Any info on the holes or passage ways being enlarged for better pressure or lube please let me know. I cant afford a nice unit and have to get what i got reliable.

JUNK

I have never drilled holes larger in the input, BUT, 3rd oil feel in the separator plate gets the drill, 3rd accumulator gone via billet servo, and use the sonnax 3rd oil capsule in the case under the 2-4 servo. Use a z-pak set to .050-.070 clearance with #7 apply in the drum. Use a .490 or bigger boost valve and make damn sure u pressure check everything on the bench (check the input drum, then place the rev drum on the input, place the pump on top of them, and re-check with air at the pump to apply the 3 clutch packs one at a time).

Any leaks? Check the teflon seals on the input if it only leaks thru the pump check.....The trans will work fine with a small leak in the 3/4, coming from any number of places. Like a tire that leaks, it can get u pretty far but in the end u need a plug and more air.

If u are using quality parts, maintain spotless/clean area to assemble, set clearances right, and use quality parts while paying attention to detail, your unit with rock until your 4k stall bakes the fluid in traffic and it fails.

Been doing-repeating this cycle for 19 years with the 4l60 and it only gets better as better parts are introduced. There are 100 things in that unit that can ruin your day, but only if your not watching them all. Study everything ATSG has on the unit, and look at all the "fixes" sonnax has for them, this will give u a good idea what to watch for

mrvedit

JUNK is obviously an expert and I'm just a novice, but let me add this...

You might also consider the OEM checkball in the drum with the simple bleed supplied in the Transgo HD2 kit. Transgo claims that at high RPM the checkball unseats and creates a large 3/4 fluid leak. I tried the spring-loaded checkball from Superior, but the capsule is so large it hit my reverse drum. WTF - I called Superior and while they claimed it fit with all OEM parts, they admitted they were creating a smaller capsule. In any case, these two companies claim this checkball leaks at high RPM.

When air checking just the drum, plug the two bleeds in the drum with your finger when testing the 3/4 piston; it should be very solid then with no other leakage.
JUNK's tire analogy is not the best because additional fluid is constantly supplied; that is why the 3/4 piston can have two bleeds; the bleeds (or leaks) just need to be very small. Enlarging the 3rd feed hole in the separator plate will give you quicker engagement and help overcome any small leaks.

I am a bit surprised by JUNK's suggestion to use the Z-Pak and with such a large clearance. It seems many other trans builders don't recommend the Z-Pak over 400HP and suggest a clearance more in the .025 to .040 range for any 3/4 clutch. I look forward to his comments and advice.

Jake's Performance

iTrader: (2)

Enlarging the holes in the actual input shaft for the 3-4 will weaken it. This is where they break typically anyway.

I've never measured the holes and calculated the area, but it is likely larger than the feed hole area.

I wouldn't suggest it.

As stated you want to kill as much of the potential leak AND crossleakage on this circuit as possible.

The new drum mention in another thread is a promising piece. I still don't think 1000 HP is the place to attempt to run a 4L60E series unit but it's good to see the envelope pushed and the new parts developed.

I have some ideas to make some MAJOR changes to the 4L60E as far as the 3-4 clutches, 2-3 shift circuit, etc. However it will require a completely new drum, new reverse input frictions and steels, some significant valve body changes for the 2-3 shift, and other changes.
I have been super busy with some other projects for the 4L80E and TH400, but I may get back on some development work on the 4L60E soon.

lt170chevelle

iTrader: (2)

Thanks for the advise guys and i was pretty amazed about the zpak at such a big clearance gap especially after the break-in and clearance gets wider.
I have been debating that drum from patc , but looks to be allot of work to get that sucker swapped out for the price.
Maybe its just time for me to swap to a 4l80e..
This is for my turbo 6.0 chevelle and i daily drive it everyday so maybe i will get better durability with a beefier trans..

mrvedit

If I ever put in a turbo, I will swap to a 4L80E. If nothing else, it will give me a chance to learn all about another trans.

JUNK

mrvedit, every trans builder uses what works for them, in the latest z-pak kits, they state 5 times on 1 sheet of paper (in RED 3 times) to MAKE SURE clearance is at .050-.070 They even include a .050 spacer in evey z-pak #001 that I have seen in the last 12 months or so, and I use it as a quick "dry check" before soaking. U could set them at .020 if it made u feel good, but pull it down at 200mi and it will be close to the clearance of the .050 pack....only difference will be the amount of 3/4 material in the pan.

I am far from an expert, but I build 2-3 "race" 4l6"x"e units a month for the last 19 years or so. Safe to say hundreds.....I was building them when there was no "e" (700r4) and saw changes EVERY year until 96, and then every couple years or so after that. 90% of the units I put together have the crap beat out of them and many would come back at some point and I get to see 1st hand the **** that just can't take it. I have seen manufacturers including GM step to the plate and address many of these issues. I only know what works from fail-learn-succeed and I got 2 decades of this particular bastard under my belt. There is a whole lot of people on this board more knowledgable than me about this unit, but WAY more THINK they are.

I am sharing what works for me, and what my long-term observations are, I would welcome any further debate on the 3/4 clearance issue as I may still learn something myself. Always a plus

performabuilt

iTrader: (25)

We generally set dry uncompressed clutch clearance at .020 to .030 once compressed a few time is abit higher this has worked out well for us. Beware of excessive clearance in HP builds with large feed holes because of what I call the Hammer effect on the drum. The greater the travel distance with a given presure the more rapid the rate of travel this can place huge impact on the end of the drum and cause it to break the lugs off of the end. Just My two cents

performabuilt

iTrader: (25)

As for the feed holes in the shaft do not enlarge them this I agree will weaken the shaft and they are allready larger than the feed hole overall

JUNK

Your 2 cents are clearly worth more than a dollar
This makes perfect sense, and something to consider. But I can assure u it won't stay that tight for long. I also notice that the last plate with the thin strip of material mics out thinner on the used packs, though it is a non-wearing part. Compressed for sure.

mrvedit

Thank you for your feedback on that. The Z-pak is a unique and a very different type of 3/4 clutch. Certainly good idea to start with what the instructions say in RED. Interesting observation that the pack will quickly wear down to 0.050 clearance regardless.

I have the Z-pak, but also the Alto Performance pack and a variety of other 3/4 clutch frictions and steels. Still deciding what to put in my current build this week. Inclined to use the Raybestos GPZ105 as this is Raybestos' latest product which they say is based on the Z-pak but as traditional frictions. They also worked great in my last month's build with 7-frictions which I am driving now. This time I hope to build an 8-friction pack with those and 0.076 Kolene steels; still need to measure it carefully. The Alto Performance pack has 9 frictions and very thin steels which worry me.

Performabuilt: Thank you for explaining the "hammer effect". I feel more comfortable with a 0.030 to 0.040 dry clearance, which IIRC is the clearance recommended with the Alto Performance pack.

performabuilt

iTrader: (25)

Yes that compression is taken into account we figure on a final around .030 + or -

lt170chevelle

iTrader: (2)

Thanks for you guys 's input.
Speaking of clutches have either of you seen the new alto one sided clutches? I have bought a pack and plan to use on this build. Cant remember the exact name off hand bt its there newest design that uses frictions on one side