Hello everyone ! I used to read this forum every time when I have tranny issues )
Now I have strange (for me of course) felling when my tranny shifts 1-2 and 2-3
So
Astro VAN 4.3 AWD 1996
Engine is stock
PCM was repaired (faulty ground on early 1996 PCM -TSB from GM)
Tranny was rebuilt by myself couple of years ago
I used new rev drum with wide alto red 2-4 band , beast sunshell and set of red alto and colene steels . Into VB I installed set HP4l60e-01 from SONNAX and 46-96 plt from TransGo (and drilled it according to SONNAX instr)
After assemble I felt 'double' 1-2 shifting and replaced oem 2nd servo to superhold servo from sonnax. So far so good but a couple month ago I felt vibration at 4th locked TC and after that lost my reverse (
Pan vas full of metal derbis and chocked oil filter.
After disassemble I found that overrun and 3-4 completely toasted and teeth stripped a half of wide cuz(or not?) torrington bearing on reaction shaft was broken and needles trapped into planet gear . Maybe I missed right rear end clearance or just '**** happens'
I replaced overrun with oem frictions and install 3-4 raybestos Z-pak (onesided fric material) and replace all bushings - all else i left as it is (looked good for me). Replace 4th servo to SONNAX superservo to complete 2-4 servo mod)
Replace accu valve pressure reg to sonnax 77777m-k (I thought it was the cause of bad shifts)
And of course I was afraid of 3-4 lost and read here on forum that it will be better to block 3-2 valve and sol and drill bigger orifice holes and block 3-4 accumulator.
So I did )
Block valves (I have a lathe at my work) and trew away 3-4 acc piston with checkball above separator plate and block oil passage to 3-4 accumulator
"I'll Add E...my personal favorite...drill 3rd feed about .140, don't block the checkball hole...block the 3-2...drill the band release hole to about .104" - did this.
Also drill 1-2 to .100 and 4th to .120
And my problem with inadequate shifting starts )
Sometimes it shifts flowless
Sometimes it kicked my *** hard
And I dont know when and how next ***** will be
My first thought was -too much drillings
So I replace my transgo separator to oem and drill 3 ,4 and band release to .093 as it was before(as sonnax recommends-but leave 2 as it is -.076 ) -and almost nothing change in shiftings ((
I check line pressure and :
70psi at idle
220 at STALL in D and R
190 at WOT on 1 and 2
120 (!!!) at 3rd
150 at 4th.
If I cruising at 10-30% of throttle in D
90-100 psi 1and 2
drops to 70 before upshift to 3rd and after change to 3rd rise to 90 for 1/3 sec and lowering to 70 (but sometimes PCM forget to lower and pressure stays 90 after rise)
4th TC lockup -still 70 even if i drive 70 mph
If I WOT -rise simultaneously according to gear
When I shut off engine (and EPC closes instantly but engine revs ) pressure rise from 70 to 120-140 and fade with rpm drops
If I rev the engine to 3000 and shut off -it rises to 240-260 psi
So I think pump is okay
I turned EPC 1/6 -and pressure rise to 90 psi at idle
1,2 -220
3-160
4-180
But shifting is hard, whinning noise at light trottle - tranny unhappy
And I turn it back
Now shifting at light throttle changes from flawless(u don't feel shift) to crisp( feells as strong pushing but uncomfortable)
At middle throttle it shifts fast and fairly good
3-2 sucks (cuz sonnax drilling small to 3-2 blocked) -eng overrevving and bump
At full throttle it shifts as DSG in sport mode and chirps tire sometimes (but shift points inadequate to engine torque)
The problem only with 0-30% throttle shifting
Why its different ?
Then I start engine and drive -it flawless until I brake before first bump stop (2 min from start). after that next upshift will be 'strong' ... or not...
when it shifts 1-2 -line pressure dont drops to 70 -stays at 90-100 -is it normal ?
Why 3-4 pressure so low ? (i understood it because pressure map in PCM -but what for?)
2-3 shifting sometimes fells like 3-4 rattles like worn off clutch before completely lock (is it raybestos clutch pack sticky enough ?)
Im kinda nervous cuz when it shifts hard -it stripped teeths onto 3-4 clutch (found such debris in pan)
What drillings will be best for this setup ?(my car is DD and i dont wanna bite my tongue at shiftings)
Sorry for my bad English (I'm non native speaker)

 

C'mon guys -nobody drive it with pressure gauge on it ?

 

I may get flamed for this because I'm new here but here goes.

Why are you putting all of these aftermarket parts and mods into this unit? Some I'm familiar with and some I'm not.
Your vehicle is probably one of the most difficult to RnR this trans out of. It's an AWD van and a 4.3, it's not a drag car.
A 60e with a few tweaks is more that capable being a great trans in you application.

You've done so many mods to your trans I don't know where to begin to advise you and maybe that's why no one else has posted?
If I were you, I'd yank it back out, fix what's broke, and put most of the stock parts back in. Get yourself an ATSG manual if you don't already have one and start over.
Sonnax makes some of the best products on the market but it doesn't mean you should but them all into your trans.

Couple things, Sonnax servo calls for way more clearance than is needed IMO. I like .040-.050". All you really needed was a $20 vette servo and superior 4th apply servo. You did well in replacing the reverse drum as most of them aren't flat anymore. Stock borg warner high energy band and a 7 count BW high energy friction in the 3/4's are all you need. I like the 3/4 clr. at .040.
Did you check the PR valve bore in the pump? Sonnax Oversized Pressure Regulator Valve - 77917-07

 

When I rebuild it I've checked everything of course (but I'm not a pro tranny builder -actually I'm a pro auto electrician )
I didnt like soft shifting at WOT -so I read the forums and ordered that I thought will be the best for it (alto red and colene steels) -now I understood that I wasted my money cause stock frictions enough for my engine
All clearances was made 0.025- 0.040 and the band 0.065 (checked week ago)
The problem is that shift feelings constantly changes from good (when I start driving) to worse (when I stop n go several bump stops ) -no constant (feels like pcm tired do the same work twice )
And also I aware of pressure map in my PCM -cause there no problem with pump and tranny itself when the same rpm: in 1-2 -190 psi , in 3-4 -150 psi at WOT
Actually I wanna know is it normal pressure for every 4l60e or I should change PCM?
And should PCM drop pressure during shifts ? Cause mine didn't
I looked to aftermarket PCM that can retard or cut sparks(ignition) on shifting to softening shifts
And I'm planning to install twinscroll turbo under the belly cause have no room under hood) but it will be not tomorrow )

 

Its perfect drag car for traffic light races ))) Nobody believe that this rusty freezer on wheels can jump

 

If you installed the Sonnax 77701-076 Servo Release “Check Valve” I would start with removing that, it does not work very well. It will cause funny 2-3 shifts at times. If the 3rd accumulator checkball capsule is leaking replace it with a stock capsule or use Superior K0136 Directional Switch Valve/Servo Capsule in place of the stock capsule. The Superior part is expensive but I like it, no more leaks at the 3rd accumulator capsule.

Yes line pressure will drop momentarily when it 1st shifts but should rise back up quickly. 120 psi in 3rd gear is low. The Superior K0136 Directional Switch may help with this.

Most builders don’t like the 3-4 Raybestos Z-pak and you couldn't pay them to use them. If the Z-pak fails on you in the future use Borg Warrener Hi-Energy green frictions.

All that said I would remove the Sonnax servo release “Check Valve” and see if that helps your problem.

 

I've checked 3rd accu checkball (In case behind 2-4servo) -its OK
Mine didn't drop pressure during 1-2 shift (my pressure gauge quite fast - I were see if it changes)
When I done drillings like it was suggested if I blocked 3-2 -I removed sonnax servo release. I didn't feel much difference with or without
Should line pressure be the same in 1-2-3-4 ? What safe pressure for 3-4 (input dram)?
After I turned EPC sol to increase pressure and turned back -I missed exact point where it was be from factory and now my pressure at 3rd = 4rd =150 psi at WOT (maybe I should replace EPC sol? What sol is better -03 or 03- ? After 03 is significantly cheaper)
Should I replace spring in accumulator valve to softest (now its medium) cause 2-4 super servo has much bigger area ?

 

Yes line pressure should be close to the same for all forward gears.
You should be safe with line pressures up to 250psi.
What is it that your transmission is doing that you are not happy with. I got lost in all of the information that you have supplied.

 

My weak 4.3 broke input shaft in half (
I was in the middle of overtaking when PCM shifts '2' and I lost thrust
3-2 shifting too slow with 0.093 band release if 3-2valve and 3-2 shifter are blocked
Engine overrev and bumps tranny
What if I drill it to .104 -.110 without enlarge '3' drilling from 0.093 to .140 as suggested here? https://ls1tech.com/forums/automatic...l#post20070196

 

Need to lay off those AWD neutral drops so the input lives longer.

 

I replaced input shaft , stator and forward with overrun clutch packs. Also drilled band release to 0.104 -downshift from 3rd became much better but 2-3 seems that band release drum too early and there is a gap in thrust
But it not always happens
Now I inclined to replace TPS nevertheless that I checked it with oscilloscope and don't find any spikes in it signal

 

have you shortend shift times in tune?

 

Nope
My PCM not supported by HP-tuners (they claim 98+ PCM) so I don't by license for my VIN (and also I don't know if I change adapter -will my license be valid on another Hp-tuners adapter)
Maybe I should change fluid to dex6 - I heard that it will be better for smoothness

 

I don't think that changing to dex6 will make a difference.

 

This is how I have my trans set up.

With Sonnax Super Hold 2nd & 4th Servos

Clutch Clearances
Reverse Input Drum .040" To .070"
Forward Clutch .030" minimum and .063" maximum
3-4 Clutches .025" minimum and .040" maximum
Band clearance of .060´minimum and .080 maximum

Separator Plate Feed Holes
Reverse .104”
Band release .104"
1-2 feed hole to .078”
2-3 shift feed hole to .155"
3-4 feed hole to .125” with a blocked 4th accum
3-2 hole to .120"
AFL balance leave it stock
Must block the 3-2 control valve to use the larger 2-3 feed hole and band release hole.

 

not saying it will fix your problems, but I believe upgrading to a '98 PCM is a straight forward upgrade. Pretty common in the GMT400 circle. That or upgrading to a '411 LS PCM but not sure if there is V6 calibrations.

 

Dexron-VI will often very slightly increase shift firmness.

I will sometimes go down one Orifice size when switching to Dexron-VI.

 

Thanks for your help Guys!
I wrote so much but my text is gone (
So i write it again in less words )
I dont know where 3-2 feed hole -its stock now
2-3 shifting now float from perfect -to harsh
3 scenarios
Perfect -fast shift without shaking my car -just exact moment for exact RPM
Sluggish - 2nd off but 3rd not ready to engage (power loss for 0.3 sec or less but it feels like I hit brake between shifting)
Too fast - 2nd not release completely when 3-4 clutch is locking -feel like ABS sys ON for 0.3-0.5 sec (or maybe its Zpack too sticky and 3-4 itself made vibration )
I can handle this, but I'm afraid of brake my second input shaft
I near to buy another more younger PCM (98+) even it wont fit my connectors (reassemble mine or build new wire harness -not difficult but takes time)

 

I do a handful of transmission flushes a year usually on other peoples vehicles. Drain pan, fill with new, remove cooler line and pump out a litre or two at a time and refill with new. On GM or anything that uses Dex III my goto is delco Dex6. I wonder if a better shifting transmission afterwards is just because of the Dex6 and not new fluid!

 

Bought P01 PCM from blaser with red and blue connectors- 12201281 serv. 12200411
And ordered OBDlink USB cable for PCMhammer
To be continued )