salemetro

iTrader: (5)

I just completed vacuum testing of a 4l60e valve body, and Am curious as to what some of the more experienced builders here might think of the results. This is my first time testing a valve body, so I have no idea what is acceptable or not. The valve body was spotless, and lightly sprayed with wd40 prior to assembly. The test bench was calibrated to 25" hg as a reference.

Thoughts?

clinebarger

Anything under 15" means there is wear, The Forward Abuse valve (12)reading is pretty low, Sonnax has a drop in oversized valve.

TCC PWM actuator (13) could use some help, But could be the End Plug. Though it is in acceptable range, It won't get any better. If your going to run a PWM delete valve, Install the new valve & retest. The TCC PWM Isolator valve (5) test will not be valid with a aftermarket delete valve.

The Actuator Feed Limit (4) looks good.

Accumulator Bushing & Valve (3). Again while 15" passes, It will wear more in service.

Vacuum testing is usually because of symptoms/failures. Example, Car comes in with a P1870 code (TCC Slip), You concentrate on the TCC PWM actuator/isolator bore, Ream/Sleeve or a Delete valve with wider lands & retest to "prove" your work.

When I first got my vacuum test kit....I used it a lot, But I find myself using it less & less (The gauge part). I use the Mat, & Plate, Pour ATF in the worm track to be tested & apply shop air to the plate so I can SEE where it is leaking (End Plug or the Bore). I find (wet air testing) to be faster & more reliable method....Mostly faster.

But doing both Vacuum & Wet Air testing is a good thorough approach!! Have fun with your new tool! Don't forget the pump testing.

salemetro

iTrader: (5)

Thanks for the reply. I had decided a few days ago to order up the Sonnax O-ringed end plug kit, and new bore plugs....as well as the sonnax forward abuse valve. The results were pretty good....almost all circuits are now at 20"....with the exception on the TransGo Acumulator bushing and valve (New) refusing to test any higher than 15". I decided to reinstall the OEM Acumulator bushing and valve...and Presto!....20" . I then mic'd the transgo valve (.460, if I remember correctly) vs the OEM valve (.327). DO you think that it's likely a defective Transgo valve? There is no visible wear in the VB bore where the accumulator bushing intalls....and again, the OEM piece is much more acceptable in terms of leakdown. Is it possible it's just due to more surface area of the Transgo valve allowing a greater percentage of leak?

I also just ordered the Transgo 4l6-iso-3 to hopefully fix the TCC PWM actuator....hopefully it fits, or I'll have to have it bored to install it.

The reason for my testing all of this, is that this is my first auto trans build....one that has had almost $4k in parts (not counting converter) thrown at....and I need to eliminate as many problems as possible. Admittedly, it's been a long headache with MANY hours of research and talking to other professionals to gain as much insight as possible. I've learned a great deal, thanks to folks like yourself being willing to share the knowledge....and it is MUCH appreciated

clinebarger

Trans Go's quality of parts vary greatly! I fear it will only get worse now that Gil Younger is no longer with us.

You need to size the Accumulator Valve diameter & Spring weight to the 2nd servo size & 2nd accumulator spring set-up. Using a TG shift kit for example, With their "Over-Under" spring set-up to extend the 1-2 accumulator range....You can run a large Accumulator valve diameter/Spring weight.
Example 2. Using a Pinless Sonnax 1-2 accumulator piston with a "single" Purple accumulator spring will require a smaller Accumulator Valve & lighter weight spring to keep the 1-2 shift firmness in check.

The Transgo 4l6-iso-3 is for GM SRTA reconditioned valve bodies ONLY.
If you purchace a TG HD-2 or Sonnanx performance pack shift kit....They come with a stock sized TCC PWM delete valve.