Jeremiah, when you say they rocked, do you mean rocked backward or settled forward from slop in the driveline?

quote:

Originally posted by Big Steve:
Jeremiah, when you say they rocked, do you mean rocked backward or settled forward from slop in the driveline?

They all rocked backwards, then MIGHT go back forward enough to reset the stage light.

Alot of back and forth so im a little confused. I have a Reid Aftermarket case, what servo would be best for me? 1000HP bracket car 2500lbs

I just installed the black Sonnex kit in my dragster trans (Reid case) last week after a band failure. I used the supplied green spring, along with a Abruzzi valvebody. 240 psi pressure. put 15 runs on it in last Saturday and it worked perfectly.

I had Abruzzi valve bodies in both of my TD transmissions using the Black cover servo, never had any issue with rocking.

Da Shoe, pick your poison black or blue and you will be fine. I have already stated my personal choice

Who knows why these particular ones did that. I had 3 come through the shop with burned bands, put the sonnax black servo in it, and they rocked. Put the abruzi spring in it, but left the black servo and it was perfect. I also know of several top dragster guys that had same exact issue. And they fixed them the same way i did. Ive heard of other not having problems just like Big Steve. All the transmissions were abruzi top dragster valvebodies that would make 275 + psi that had issues.

Jeremiah, are you saying Marco has his own servo spring?

quote:

Originally posted by Big Steve:
Jeremiah, are you saying Marco has his own servo spring?

Everytime someone brought me a new abruzi valvebody, it came with a servo spring, and it feels softer than a stock spring. It is longer, but it is softer.

329L....SEEN THE SAME THING...FTI ALUMINUM V.B. COMES WITH THEIR OWN SERVO SPRING....I TEST THEM IN A VALVE SPRING CHECKER...ONLY GET ABOUT 140 lbs. SOFTER THAN THE SONNAX GREEN SPRING...THE HUGHES SERVO SPRING TESTS THE SAME..140 lbs. I'VE AIR TESTED THE SERVO WITH BOTH .SONNAX & HUGHES SPRINGS..THE GREEN SPRING SLAMS
BACK WAY FASTER & HARDER...AT LEAST TO THE NAKED EYE...

And we need that servo to slam off as fast as possible, that IS the weak spot that has been in the powerglide from the beginning. A burned/tore up band is normally because the servo isnt coming off as fast as it should. A servo ALWAYS has pressure, it just changes directions, that is why you see pressure all the time if you data log it, and a spike when the car shifts. And the higher you run the line pressure, the more time it takes to switch the servo around.

But if it comes off before the high clutch is fully applied will cause a shift flare was always my belief. Even tho band release and high clutch apply are being fed pressure from the same circuit Its a timing thing in high HP applications

quote:

Originally posted by Big Steve:
But if it comes off before the high clutch is fully applied will cause a shift flare was always my belief. Even tho band release and high clutch apply are being fed pressure from the same circuit Its a timing thing in high HP applications

Correct, and removing some springs in the high gear clutch pack, will speed the apply up.

How many springs are you removing?

I went a different direction installing a flow restrictor in the case feeding the servo release. This was on a recommendation from Hutch

3 SKIP 1

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$35, plus the ride, will get you a new sonnax 28821-02K
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quote:

Originally posted by imakehp:
Reading up on these servo kits it appears they only help/improve things when line pressures are over 200lbs......correct?
Also, it was mentioned earlier that this servo kit is a must if you use a button to back up.....why?
Finally, can this kit be installed without dropping the pan or even further disassembly?

Thanks,

Dave you will have to remove the front pump to be able to access the band apply strut. When you pull the old servo out that strut can/will fall into the pan. You will have to hold the strut in place while you install the new servo.

I would imagine your trans has more pressure than 200 psi. With the higher pressure you need to at least change the servo spring due to the incorrect servo bias that is an issue with higher trans pressure and the stock spring.


I believe the reference of using the button and backing up is referring to what can happen when the band does not hold properly when being on the TB and the car rocks back.

It is pretty important to have a general idea on where line pressure should be, when installing the servo. Just because it was x at one time, doesnt mean it is still there. But if you do have an idea, just follow the instructions on the install and you will be fine. I have changed them before with trans on bench and pan and valvebody off. I got lucky and didnt drop the strut with having the transmission upside down on bench.

I just gotta say, this is an EXCELLENT topic, lots of good useful information exchanged, and no drama.
Exactly what the DRR Tech Talk forum should be.
Thanks Guys!

I use the 28821-20K in both my aftermarket cases with BTE Pro brakes, one cast one aluminum. Line pressure 225-230. Going in at idle 13-1400 no movement from the car going on TB. Aso using 668 fluid.