Hi everyone, I am getting ready to go back into the trans I built last winter to do some upgrades and fix some errors that I made in the build. I did pre-repair pressure tests this morning to get base line values and got some troubling results. Min TV, in P,N,D,3, manual 1 and 2, @ 1,000rpm pressure is 90psi. R is 110psi. At full TV, 1,000rpm, pressures are P-105, R-100, N-110, D-95, 3-100, man 1&2-100. At 2,000rpm, full TV, pressures are P&N-220, R-210, D-190, 3-200, man 1&2-210. When I open the throttle with the TV locked at full travel, pressure in R,D and 3 jumps to 240 before falling back to the readings above. I wonder if this is the pressure relief valve opening. I want that the hold to 300psi if possible. The pressure readings were steady(no wiggly needle) in all tests.

This unit has .500 boost and .296 rev boost valves with a high rate pressure relief valve spring, and a new 10 vane pump. I did a full rebuild with all new seals and gaskets about 2,500 miles ago. I know there are several things that could cause this behavior. Does anyone have any thoughts? What jumps to mind? Damaged pump? Blown gasket? Damaged sealing ring(s)?

Thanks for any help.

 

The pressures are ok at the 2,000 rpm mark, so you are ok. See what the pressures at WOT when going through the gears. If they are the same or even higher, then this is good.

 

Thanks Dana, and thanks very much for your help with this transmission. I am very happy that I chose to go with Pro Built Automatics on this redo.

For a quick recap on my transmission saga, I built this unit last winter after the 3-4 clutches failed in September. The unit had originally been built for me by a shop in Portland and had actually held up very well over 25K miles of abuse. It was probably the high rev 2-3 upshifts that eventually killed it.

On the rebuild last year, I went with a big company who has a great looking website and seemed to offer alot of great parts at good prices. I ended up having a tough time getting my parts order right and an even harder time getting any useful answers to technical questions. Aside from dealing with a big company because they had a "great looking website", my other mistakes on the build were as follows:

1- Using inferior 3-4 clutch material. 2- Not verifying line pressure before I drove the car. 3- Not verifying that the TCC worked before taking a long highway cruise in hot weather. 4- Not addressing the inadequate cooler system before running the new transmission. 5- Going with the cheaper alternative on torque converter choices.(just gave a year old $400 converter to my trans builder buddy as junk)

After 2,000 miles of pretty good shifting following the build, I took the car on a highway cruise in 95 degree heat. The TCC never worked after the build. I fooled with it for a minute one day to see why, then let it go(idiot). It was after this hot day cruise that I noticed the 2-3 shift wasn't the same. The shift had been nice and firm, now it was softer. Then one day it just wouldn't get 3rd at all. I also felt the trans bind between 2nd and 3rd a couple of times and thought that maybe it was a shift valve problem.

On teardown of the unit. I found the input housing full of 3-4 clutch material. It was as if the friction paper had de-laminated from the steel plates and come off in chunks. I also found that the input shaft had worn uneven, more on side, against the front stator support bushing. I was afraid the shaft was bent or something. After looking things over more, I found that the pressure plate also had a wear mark one side of it's interior radius. I realized that with the frictions gone from the huge 3-4 clutch stack, there was about .200" clearance in the stack. This allowed the 3-4 pressure plate to side step the apply ring and get caught in a bind between the apply ring and the input ring gear when the unit tried to engage 3rd gear. Fortunately, the input gear is fine and the pressure plate is made from some kind of ultra hard alloy so aside from being shined up a little on one, it's fine too.

Between the friction material and the side loading of the input shaft, the pump was also shot. So, now the unit has a new pump(really great pump from Oregon Torque Converter). The new pump came with stator support installed with updated bushings throughout and the high rev spring already in place. I swapped in Transgo steel pump rings. I replaced the damaged input shaft with the original shaft that I still had on hand. It has new High Energy 3-4 clutches from Pro Built Automatics. I went with a thick 8 x .080" friction stack this time, using 6 .080" steels and one .096" steel to set clearance at .045". Along with the new 3-4 clutches, I did a small modification to the Smart Tech Housing. The housing takes a bolt on backing plate that fits the housing rear tight. This allows no place for cooling fluid to pass through from the back of the 3-4 clutches. I drilled a ring of 1/8" holes(5 total) around the housing, right below the backing plate to allow fluid to pass through. I hope this improves cooling.

I also did the shift kit from Pro Built on the valve body. I installed the Sonnax superhold 4th servo(dual piston) that has the largest apply area of any 4th servo. I already had the Superior 2nd servo and reused it. Dana sent me a viton seal to replace the crappy plastic input/output shaft seal that came in the Transtek kit last year, along with all of the other seals and gaskets needed to complete the repair. Dana ordered up a 9.5" 3,500 stall Edge converter for me that works great. So much better than the 12" chunk it replaced.

All of the other clutches and the 2-4 band looked great, no sign of heat damage at all, so they all got cleaned and reused. After the redo, the pressures are better than before. Max pressure in every gear is 260psi and line rise is good. The trans shifts great, especially into 3rd gear. Light throttle 1-2 shift is a little soft and the shift kit did nothing that should have affected that shift. I'm wondering if I left the seal off of the 2nd accumulator piston(oops).

For now, it's raining and will be for the next 5+ months. The car is safely tucked away in it's dry winter resting place, under it's nice warm cover. Sometime in the next few months I'll drop the pan and check that accumulator. I'll also recheck the TCC since I didn't notice it engaging on the way home. Before next summer, I will make sure that the TCC is working and that all my shifts are perfect.

Thank you again Dana and Pro Built Automatics! Working with you on this project has been great.

 

If you installed my modified Shift kit, then the 1-2 part throttle shifts will be smooth and the shift getting quicker and firmer with more throttle. That is the way it is supposed to be.

 

That is how the shift is. I'm just not used to the soft shift at light throttle. The shift at half throttle+ is sharp and quick. I'll be driving it back to the shop at some point to recheck the TCC controls. I'll see if maybe the shift grows on me. Thanks again Dana.

 

I am using Dana's shift kit aswell and at light throttle you can almost not feel it shift. Once you start to press the go pedal though, the shifts become quick and firm.

 

Thanks morgsie, I took the car out this weekend and that is what I'm feeling. I was just caught a little off guard by the change. I did this unit last winter and got good advice from Dana then. That's why I went with Pro Built Automatics on this repair. I'm very pleased that I chose to go this route. Once again, Thank you Dana.

Now I just need to get this TCC working. I'll have to get the car to the shop and do some testing to figure out what's missing. I'm either not gettintg power from the relay, I don't have good ground through the pressure switches, or the solenoid is no good. I'm thinking it's probably the solenoid.

Right now, my wife just bought a new car and money is tight, probably through Christmas. So my car has sit in it's warm safe garage and wait.

 

I was caught off guard aswell. At light throttle it doesn't even feel like the trans made a gear change, which is usually a bad thing! But at light throttle and light load I doubt this will hurt the clutch packs at all.

I bought a brand new Delco (internal) trans harness for $50 for my TBI B-body trans. The outer insulation was very brittle and falling apart. If you're interested I can look for the part number, it should be the same harness as the F-bodies.

PS: The Delco harness comes with a new lockup solenoid already wired.

 

The new harness sounds interesting. My harness is in good shape though. The only question is my connections. I'm thinking I may have crimped over the insulation at the solenoid. I'm going to do pinpoint testing either this weekend or next and I should be able to get to the root issue pretty quickly.

Yeah, the 1-2 shift is not what I'm used to. For a bit of history on this thing, before last winter's build, the trans had bang shifted into 2nd ever since I had it professionally built in 2000. What I found on teardown last year was this weird spring in the 2nd accumulator that was soft but also had so many coils it only allowed the piston to move about 1/4 travel. At light throttle, the 1-2 shift would bounce-as in engage, release, engage real quick and hard. I figured that it was the weird spring that was causing this. At hard throttle the shift was fast and solid.

I replaced the funky spring with a stiff brown spring that I got from another source, and put the Transgo black spring in the 2nd accumulator valve, like Dana uses. The shift after that was perfect for my taste. It was firm but not harsh at light throttle, definitely felt the shift. At heavy throttle, it was very firm and quick, like it is now. When I did Dana's upgrades, I used the same brown spring in the 2nd accumulator rather than use the Transgo accumulator stack that Dana gave me. Dana uses the same black Transgo spring in the accumulator valve that I already had. That's why I think I may have left the piston seal out. The 2nd gear shift should have been the same as before. I still have the old accumulator too and it's in good shape. I may just swap it back in. I'll at least check to see if I left the piston seal out of the one Dana supplied.

You see, the way the 2nd accumulator and accumulator valve work is that at light throttle, there is low pressure behind the accumulator valve and only the small black spring holds the valve at rest. When pressure is applied to the accumulator valve from the accumulator piston being forced down it's bore, the valve moves easily and the pressure is exhausted though the accumulator valve. In this case, the only thing holding the accumulator piston from easily moving down the bore is the accumulator spring itself and the tension of the small black spring against the accumulator valve. At greater throttle opening, MTV pressure increases at the back of the accumulator valve, preventing it from moving and creating resistance against movement of the accumulator piston. This produces a firmer shift with more throttle opening.

Dana uses the Transgo black spring in the accumulator valve and the Transgo accumulator spring stack to produce a shift that is mild at light throttle and progressively firmer as throttle pressure increases. What I had before the shift kit install was pretty much the same but with a stiffer accumulator spring that produced a firmer shift at light throttle, which I prefer. The only thing that would have made the shift softer would be fluid getting by the accumulator piston. Or else maybe a leak at the servo itself but I'm pretty sure that went together right. I'll check it though if I find out the seal is on the accum piston. It will suck to have to redo the servo piston seal now since there is no way the Sonnax superhold 4th servo is coming out with the trans in the car. But I'll do whatever it takes.

I love the hi energy clutches Dana provided for me. I can already feel the difference in 3rd gear. Plus, with his shift kit I can shift between 2nd and 3rd and back without worrying about burning clutches. I also love the Edge converter. I am very pleased that I chose to go with Dana on this. Dana knows these transmissions and I've learned a lot from him. I will always recommend him for anyone looking for parts, advice, upgrades or a pre-built unit.

I did like my old 2nd shift better than what I have now. Good thing is, I have learned enough playing with this thing and from guys like Dana that I know how to change it back without affecting all the other good stuff in Dana's shift kit.

 

Ha! I just pulled the 2nd accumulator and guess what? No piston seal! I'm so glad that it was something so simple. This trans works so well now with Pro Built's upgrades. The soft 2nd shift was the only shifting issue.