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Performance transmission build
Ok, time to prove the rumors right and start unveiling the performance 4eat build. I've been working on the ultimate 4eat rebuild for the svx. There's a lot involved in this so documenting and illustrating what I'm doing is difficult. Expect the thread and organization of pictures to be sloppy. There will be a a huge # of pictures posted; even still a lot won't be in pictures because no one was around to take a picture while I had my hands in that particular part.
The original plan was put together the ultimate rebuild kit consisting of the parts I am using to build the transmission for the sub 10 second car I'm putting together. It turned out more practical to offer the compete built transmissions (and I came back and edited this line to say that). The build is a job and a half and I found several critical points of failures that most transmission shops will probably just ignore even given the correct parts. I'll try to point them out as they pop up in pictures. The build parts start with a complete set of super quality seals and gaskets. Most of these seals are from the same manufacturer as OEM but there are also some that are improved to prevent the leaks that create the pressure drops that are partly responsible for clutch pack burn outs and planetary over heating. On to that are added parts to modify the fluid pressures of the various circuits. These are mostly springs and plungers in the valve body and accumulators but we also modify some fluid paths. What we are doing here is increasing the apply pressures on the clutch packs to increase their holding power, increasing the fluid flow to the planetary to improve lubrication, and modifying some shift pressures to quicken shifts. The next major group of parts are the friction sets. Here we are replacing the frictions with graphite frictions which both last longer under daily driving conditions and have a higher friction coefficient under higher power levels. We use some special retaining plates to let us fit in more clutches for even higher power levels. This is most of the parts originally planned to be used in the kit. Some more have been added during the course of the project. On the transmissions that I'm building I also replace the solenoids and torque converter. http://www.ecutune.com/posts/4eat/DSC_3910.jpg |
Here are some photos of the valve body removal.
pan off http://www.ecutune.com/posts/4eat/vb...l/DSC_3782.jpg bolts reatining valve body off http://www.ecutune.com/posts/4eat/vb...l/DSC_3799.jpg valve body pulled up and flipped over here you can see the accumulators in the transmission body..more on them later http://www.ecutune.com/posts/4eat/vb...l/DSC_3796.jpg valve body removed now you can see the planetary set..on it later http://www.ecutune.com/posts/4eat/vb...l/DSC_3816.jpg |
With the valve body removed we clean the parts with kerosene and make the modifications to it modify the line pressure and various circuit pressures. Most of the modifications involve replacing the springs on the plungers which maintain the pressure for their particular circuit. We also replace a couple plungers and enlarge a fluid path in the plate between the upper and lower valve body halves and block off another.
http://www.ecutune.com/posts/4eat/vbmod/DSC_3920.jpg http://www.ecutune.com/posts/4eat/vbmod/DSC_3922.jpg http://www.ecutune.com/posts/4eat/vbmod/DSC_3923.jpg http://www.ecutune.com/posts/4eat/vbmod/DSC_3924.jpg http://www.ecutune.com/posts/4eat/vbmod/DSC_3926.jpg http://www.ecutune.com/posts/4eat/vbmod/DSC_3927.jpg |
Here are some sparse pictures of dissassembling the transmission.
gear case with extension housing and differential case removed http://www.ecutune.com/posts/4eat/di...y/DSC_3961.jpg Staked nut on drive gear on back end of pinion. http://www.ecutune.com/posts/4eat/di...y/DSC_3964.jpg drive gear being pulled off pinion http://www.ecutune.com/posts/4eat/di...y/DSC_3966.jpg pinion unbolted from pump and being pulled out of case note the tube around the input shaft..this tube has bonded rubber seals on each side and is a special order part most rebuilders don't replace...that's the cause of contamination between the gear oil and atf. It should always be replaced. http://www.ecutune.com/posts/4eat/di...y/DSC_3968.jpg pump being pulled off of gear case note the lathe cut seals on the pump..they shrink and are another point of failure..these are replaced with better versions http://www.ecutune.com/posts/4eat/di...y/DSC_3969.jpg gear case with planetary removed and the accumulator for the band apply in my hands note the seals on the band apply accumulator..another point of failure..they wear and cause poor apply pressure and brake band burn out http://www.ecutune.com/posts/4eat/di...y/DSC_3970.jpg |
I'll have a lot more planetary pictures soon. For now I just have some of the forward clutch drum to illustrate how they work and why most transmission rebuilds done on the 4eat skip right by a couple importan points of failure.
the forward clutch drum houses both the forward clutch and over running clutch. Each is a stack of frictions, alternating steel plates and friction plates, plus dish plates, retaining plates, circlips, and pistons which under hydraulic pressure engage the clutches. The friction sets are easy enough remove and are what the transmission shops usually remove and replace in a rebuild. The pistons are more difficult to remove only because you have to either have the special tools from the factory or just the right set up to be able to press the spring loaded pistons in order to remove and install the circlips that retain them. The truth is you can pretty much count on your average transmission shop skipping right past this step and there are several piston seals in this trans that are prone to failure. We of course replace those seals with improved seals. empty forward clutch drum in the press to remove the circlip retaining the forward and overrunning clutch pistons. http://www.ecutune.com/posts/4eat/forward/DSC_3983.jpg forward and over running clutch pistons removed and with new seals installed note each piston has seals on both it's inner and outer seals and grooves are covered with trans gel http://www.ecutune.com/posts/4eat/forward/DSC_3987.jpg forward clutch drum reassembled with new improved friction sets installed. graphite frictions are used for both the over running clutch and forward clutch A special retaining plate is used and the # of frictions for the forward clutch are increased. http://www.ecutune.com/posts/4eat/forward/DSC_3988.jpg |
each clutch pack in the planetary is done much the same as the forward clutch pack. I'll post pictures of each as the planetary goes back in soon.
The low reverse clutch set mounts in the transmission and has a couple points of failure in it. I'll post pictures on that soon too. The transfer clutch is a little different and has a point of failure that not only takes out the transfer clutch but clogs up other fluid paths and takes out the whole trans. Another of those special order parts that no one ever has on hand or bothers with. I'll post pictures on that soon too. we make some modifications to the shift accumulators. I'll post pictures on that soon too. that's it for now |
I've asked a few customers what they think and I think what I'm going to do is offer the two toms the option of getting either complete transmissions for them to install or rebuild kits and give the general public only the option of getting the complete transmissions.
Everyone seems aggreed that the local transmission shop can't be trusted to put in the huge amounts of time required to do it right. |
another thought I just had was that it would probably work well for people to order the complete transmissions from me and have me ship them to the two toms so that they can put the transmissions on credit card and I assume pay whichever tom cash for the install
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speeking of installation. A dedicated transmission cooler with it's own fan and 180 degree thermostat should be installed in the drivers fender. The radiator cooler should be bypassed.
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Finally!
Someone we know is working on the auto. Instead of just saying "just get a manual". I emailed Level-10 with questions several times and they never even bothered to email me back. Awesome job! |
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Cool, lot of technical pictures.
Are you going to improve the gear ratios and the differential too? If you want to buy an used SVX stock ratio tranny, let me know. I have one sitting in the storage. The front differential was bad but the tranny itself was still shifting fine, was told it was rebuilt 20k before I bought the car. But I replaced 4.44 tranny on my yellow. |
Wow. Can't wait to hear about the results. Might want to enlarge the casting slightly where the brake band outside bolt is. That way a gear wrench will fit on the 17mm bolt and make adjustments easier. The wall of my gear wrench was to thick and the casting was in the way.
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Michael,
Nice! I like the idea of the two Toms doing the build-up/install. Shipping transmissions around is going to add cost that may put the mod out of the reach of many. 10 second SVX? Gonna have to take some weight out of that bad boy first!;) :cool: -Bill |
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