April 17, 2024, 12:40 PM
ski_dwn_itWhat do you think..
This winter I took my internals out of my Rossler stock PG case and moved them to a Reids case. Bought new band, forward and reverse clutches. Also upgraded the servo to a sonnex guided piston.
Pressures were all good 1st @2200 230
2nd 2200 230
Reverse 230
Took it for some quick drives around the house totaling about 5 miles.
Went to strip and car made two solid passes 5.7@119. 60ft and 330ft were .002 different with. 02 variation occurring in last interval. Track was opening day. Started to tune the car with a reduction in timing to see if I could tighten the last interval.
Launched the car for 3rd run and it felt like it blew the tires off. Trans didn't feel happy after. Pulled it apart and it burned the band out. Pressures checked prior to disassembly were exactly the same as after rebuild.
Fluid level was set at pan rail. Deep pan with filter extension.
Band was adjusted to Reid's instructions at 40in lbs and 4 turns out.
What are you guys thoughts on the cause? Have new stuff coming tomorrow.
April 17, 2024, 12:55 PM
TH383I know my sonnax servo had instructions for making sure the servo pin fits correctly in case especially on a/m cases. I set my reid case to the old 72 in pds and back it off 3.5-4 turns and my band looked brand knew after 3 seasons
April 17, 2024, 01:32 PM
FTI40 in-lbs and 4 turns is too loose. We recommend 73 in-lbs and 3.5 turns. On new bands/transmissions we recommend checking this after the first or second race. Just to make sure all is well after any band stretch or part settling that may of occurred.
April 17, 2024, 08:44 PM
ski_dwn_itFYI. You guys use that sonnex guided servo?
April 18, 2024, 07:42 AM
TH383I went with the smart ratio servo. I believe its step above the guided servo. The guided servo I believe you have to shim the spring depending on what pressure you have.
https://www.sonnax.com/parts/4...atio-style-servo-kitApril 18, 2024, 07:50 AM
rustyi use the purple one.it does have to match pump pressure by shimming.there are many things that could burn the band.was this a new build,are there any other new changes,new or different valve body.was only the center of the band burned.
April 18, 2024, 11:23 AM
TOP38You also may want to have that case checked, I hear that there are copy cat Reid cases out there from China...
April 19, 2024, 07:00 AM
ski_dwn_itValve body was the same, case came right from Reid's.
I think I either set the band wrong.. Followed Reid's instructions for 40.inlb and 4 turns.
Had ATF at pan rail... Should have been 3/4 inch above.
Or the guided servo with green spring isn't compatible.
My pressure were all good before and after.
Last bit of info. Called two major trans builders. One says the servo is the prob and they've seen 8 bands burned using them. No rhyme or reason why. Told me to throw it in garage.
Second builder didn't even know what they were and they build some of the highest end stuff out there.
I put new band in, old servo, and going to fill it to 3/4 above. Would love to experiment to find out what exactly it was but that isn't happening.
The more I thought about the guided servo it really doesn't make sense why it's "better". It original design passes thru the case quite a bit guiding the shaft. There is no way it can **** in there with that much "land". The rear guiding I can't see adding much to it. I'm wondering if the rear pocket for the guided is becoming pressurized not allowing the piston to return as it should? There are grooves and a pocket they connect to. But not sure if they flow enough.
April 24, 2024, 07:49 AM
FTIquote:
Originally posted by ski_dwn_it:
Valve body was the same, case came right from Reid's.
I think I either set the band wrong.. Followed Reid's instructions for 40.inlb and 4 turns.
Had ATF at pan rail... Should have been 3/4 inch above.
Or the guided servo with green spring isn't compatible.
My pressure were all good before and after.
Last bit of info. Called two major trans builders. One says the servo is the prob and they've seen 8 bands burned using them. No rhyme or reason why. Told me to throw it in garage.
Second builder didn't even know what they were and they build some of the highest end stuff out there.
I put new band in, old servo, and going to fill it to 3/4 above. Would love to experiment to find out what exactly it was but that isn't happening.
The more I thought about the guided servo it really doesn't make sense why it's "better". It original design passes thru the case quite a bit guiding the shaft. There is no way it can **** in there with that much "land". The rear guiding I can't see adding much to it. I'm wondering if the rear pocket for the guided is becoming pressurized not allowing the piston to return as it should? There are grooves and a pocket they connect to. But not sure if they flow enough.
For what its worth, we don't use anything fancy on any of our servo setups. Just a traditional style dual ring servo and a billet cover with a servo spring.
April 24, 2024, 09:35 AM
rustythere are some really good vid on servoand how they work with the spring,explaining why the band burns.in the end if the drum is trying to turn the band cant hold it.matching the spring to the pressure is critical.
