Last points race the sprag quit doing its job. Pulled TC and guy said is destroyed. Went spragless and tested last night. Old converter tied down on trailer against brake no 2 step stalled at 4550 on peak. New spragless goes to 5250, looser than expected.

Went to TNT and tested, few cars and not many slick cars.

1st pass .005 RT, 2nd -.004, after that felt small shudder on brake release .045, .041 RT. Pit help missed vid of rear tire. Last pass got vid of significant tire slip. Track going away, not unusual and car moved right on last pass.

My primary question: is there anything in glide that can shudder or give that feeling on brake release? Car sounds runs different off converter but ET and MPH was right where is was during sprag failure. Final pass matched dial still on back window from prior race. Is possible was just track going away.

Car is 3250 lbs, 357 SBC with 12.4 CR and small port aluminum heads. Sportsman brake glide, 9" moser w/35 spline axles and 4.11 gears, 29.5 M/T (could not find Hoosier 29s) 7.1x to 7.2x @ 94 MPH.

First gear is the band, check band adjustment to see if it's loose. How does the fluid look? probably track on TNT night.

Fluid good, no burn smell or discolor. Will verify adjustment to be safe. If camera had not got goofy on the passes would have been certain. Last pass camera worked and tire slip at release was clear and felt like extended version of earlier runs. First 2 passes felt nothing.

Thanks for point about band.

is this the same brake,solenoid and brake vale.are you leaving at higher rpm.the brake valve may not hold pressure at peak rpm right before relase

Yes all identical to sprag converter. Never tried to back or move, just slight shudder on release of button. Caught last extended shudder on vid and was real tire slip. Gave extra time to cool before last pass in case heat related and it was worst but shudder felt same only extended.

Pulled pan before pulling converter looking for metal, nothing of consequence other than light spot of clutch dust. Trans came out of high 5 second doorcar.

if it is tire slip causing what you are feeling, it may be as simole as new convertor hitting tire harder due to more stall,try lowering launch or work on suspension

quote:

Originally posted by rusty:
if it is tire slip causing what you are feeling, it may be as simole as new convertor hitting tire harder due to more stall,try lowering launch or work on suspension

Definitely a likely item. I set car up to react as fast as possible to see how much spragless slows it. The only adjust was to raise high side limiter as it was tickling smart rev limiter top of 1st and in high 1st pass. That eliminated that. Tires had more PSI, air bags higher, no extra weight to slow rise. Would be way red with unbroke sprag converter. Likely just overpowered then tnt track conditions.

When trying new combo/setup I always make first passes at quickest VRT and work back. Only 1 lane sprayed on TNT and 1st 2 passes solid off line, got progressively worse through night. I got baseline and can work toward getting competitive again. The shudder only concerns me as T400 in past would feel same when tires, pump or clutches going away. No band/drum in them.

That was simple, put gauge on servo cover. Pressure low, 180 initially, dropping to 130 as it warmed. Recovery really slowed on transbrake application. Time to swap trans and take apart. Worn pump, internal leaks or seals?

quote:

Originally posted by muggs:
That was simple, put gauge on servo cover. Pressure low, 180 initially, dropping to 130 as it warmed. Recovery really slowed on transbrake application. Time to swap trans and take apart. Worn pump, internal leaks or seals?

Do all your pressure tests at 2,000 rpm's plus, where pressure tops out.

Anytime you communicate transmission pressure's, you should be referring to the pressure at 2,000 rpm's plus, where it tops out.

180 psi @ 2000 rpm's plus, is stock powerglide transmission pressure, it's good to probably 550-650hp possibly.

Make sure to do stall test after freshen up. Getting the line pressure up, will most likely drop the stall a touch. I have seen as much as 200-300 stall loss when pump pressure was really low, and it was brought back up to 225 psi.

Was at 2000 RPM. Have experience with T400s, little with glides. Started out 180 and recovered quick with brake application. Few minutes warming, not hot dropped fast. Most common I seen with T400 was worn pump gears. Even cold never saw 200, this trans came from 5.70/80 car. The shudder did not equal tire slip feel, felt like something rotating few turns and getting worse. Trans had sat few years after refresh before install. I am thinking put spare trans in and take this one apart.

quote:

Originally posted by muggs:
Was at 2000 RPM. Have experience with T400s, little with glides. Started out 180 and recovered quick with brake application. Few minutes warming, not hot dropped fast. Most common I seen with T400 was worn pump gears. Even cold never saw 200, this trans came from 5.70/80 car. The shudder did not equal tire slip feel, felt like something rotating few turns and getting worse. Trans had sat few years after refresh before install. I am thinking put spare trans in and take this one apart.

Sounds reasonable.

You could try a pump in it, test again. I got a pump you could try I freshened, cheap - $100.

Pumps are high rent these days.

Pull the pump and high drum, inspect band and high clutches. Put back together accordingly.

Just did a full test again. Even bled gauge line before and picked up nothing. At 2000 after start up, 175 -180, brake application recovered reasonable? Let idle in park, into 1st gear 160 at 2000rpm. At idle (1150) 80 -90 in 1st. Bring up to 2000, 160 and very slow recovery with brake application. 3rd try below 150 at 2000.

Appreciate the insights. Will swap other trans in and take this apart. I swapped trans before world finals in 20 when end converter bearing failed. Took apart to look for seal pump damage from metal found in pan. No damage in pump so screen kept it out.

quote:

Originally posted by muggs:
Just did a full test again. Even bled gauge line before and picked up nothing. At 2000 after start up, 175 -180, brake application recovered reasonable? Let idle in park, into 1st gear 160 at 2000rpm. At idle (1150) 80 -90 in 1st. Bring up to 2000, 160 and very slow recovery with brake application. 3rd try below 150 at 2000.

Appreciate the insights. Will swap other trans in and take this apart. I swapped trans before world finals in 20 when end converter bearing failed. Took apart to look for seal pump damage from metal found in pan. No damage in pump so screen kept it out.

Yeah, your fine with that one.

Split the pump on the other, it'll have noticeable observable wear or damage most likely.

Good you did these checks before it sizzled to worthless.

Have you pulled the Valve body apart during the R&R and inspected the boost Valve and spring?
This regulates line pressure. Various spring colors with various pressures. How much metal was in that trans?

Will have apart next week. Pump bad will send you PM.

quote:

Originally posted by muggs:
Will have apart next week. Pump bad will send you PM.

I got a bunch of em. The uptown crackers like the 7 bolt $500 pumps, been using those more. They are pretty nice for high power apps.