Line pressure help

[Dave Levey]

I recently rebuilt my trans to the specs by CK in his manual including dual feeding direct, at extremely light acceleration the shifts are very very soft at 1/4 to 1/2 throttle they are tire barking crisp. At WOT they are back to soft. another unique thing is that with the convertor locked when shifting from two to three it unlocks before the shift occurs then locks again after the shift.
Pressure readings are

p 65 -225
r 100-150
od 65-175
d 65-160
2 160-160
1 150-150

Any ideas where to start, without better guidance I will start swapping parts, (PR springs, valve body and spacer) The last build on the trans had the red TCI spacer plate and a shorter pr spring and pressures in OD were 75 and 190 if that helps.

 

[jakeshoe]

What pan are you using?

Static pressures don't look out of line to me, but if it's sucking air while driving, pressures will suffer.

 

[Dave Levey]

I run a stock pan with a 700 filter, the pressures are rock steady with only a blip at the shifts, I ffel the pressures are low be cause in CK's manual he specs 90 psi at min tv and 240 at max tv in p-n-od and d I am only seeing 65-170 on avg. IN d1 and d2 he specs 155/300 and I am at 155/160.

 

[chris718]

remove and inspect boost valves in pump.verify oil signal pipe on the valve body is installed and doesnt leak.in vbody check the tv limit valve that feeds the plunger as well

 

[Dave Levey]

HI Chris,

I tried calling you a few times today, I will try again tomorrow.

I did drop the valve body and recheck all the springs and valves and they all seemed ok, for kicks I did try another valve body after swapping the springs from your shift kit but there was no change, I pulled the pr valve, boost valves and spring and found nothing wrong. I did reassemble it with a stiffer PR spring and it only picked up the pressure 10# at min tv with no change at max tv.

 

[jakeshoe]

What are your pump clearances?

 

[Dave Levey]

The pump was supplied by a reputable trans builder so I never checked it, I never even checked line pressures before as I ASSumed I was buying good stuff, seeing as the last rebuild only lasted a handfull of passes and the 2-3 shift never felt great I did the dual feed thing this time and drilled the .060 hole in the direct drum and the shift feels worse then before so I do not even want to take it to the track, I checked line pressure as the first step of diagnosing the problem and this where I am at.

 

[Dave Levey]

update

I may have found the problem, upon disassembly I found a foreign object embedded in the case between cirquits 13(drive 3) and 28(mod.throttle valve) the gasket was worn through from the object the entire width of the case passage so I believe I had a cross leak. I also found that the band was burned only in the very center about 1/2 wide but the entire circumfrance of the band, there was no other abnormal wear on the band. The direct koleen steels looked as if the koleen coating was worn very thin to allmost a shade of gray, the direct clutches appeared darker then normal but could this be caused by the kolleen coating ?

 

[chris718]

the oxide coat on the steels will go thin after start up and initial appy,no worries.center burnt in the band is usually an uneven band surface on tye drum or too much pressure causing the band to apply only in the middle during initial application.

 

[bison]

The pump was supplied by a reputable trans builder so I never checked it, I never even checked line pressures before as I ASSumed I was buying good stuff, seeing as the last rebuild only lasted a handfull of passes and the 2-3 shift never felt great I did the dual feed thing this time and drilled the .060 hole in the direct drum and the shift feels worse then before so I do not even want to take it to the track, I checked line pressure as the first step of diagnosing the problem and this where I am at.

The pump clearances could be a problem. I would verify all clearances before putting it back in.

 

[Dave Levey]

good news on the directs but does the cross leak in those cirquits explain the shift or pressure issues ?

 

[Russ Merritt]

I did the dual feed thing this time and drilled the .060 hole in the direct drum

A .060 hole in the direct drum?