So now we’re into the internals of the transmission. This is the modifications that are necessary in the 68 RF II starting with the pump going to the clutch drums and all the clutch packs, and the shafts in the planetaries. All the things would be modified. And again, with a 68 RFE, it’s required some pretty extensive modifications because it’s pretty wimpy training, you know.
Obviously, the 68 was started out, started life out as a gas transmission. This is a 545, one was kind of grown up in the 68. Of course most of the parts inside the 68 are interchangeable with a 545 transmission which is your gas tranny or your gas hemi tranny.
Of course, a few cars got a little bit bigger and that’s what we have to deal with. So it started in front of the tranny, the heart of the transmission of course is always the pump.
The pump is kind of a unique pump design. Instead of having just kind of a crescent style pump, it uses a pump with a high and a low pressure design, which has a pump on the inside which is hooked to your crankshaft the torque converter. Then you use your two pinion gears to compress fluid in the high and the low side, which is a great design, but the problem is it really wears out. This is the front of it where the torque converter goes into it, and all your torque converter weight is supported by the pump gear. In that pump gear it literally just grinds into the mystery metal that we call aluminum.
So again, Chrysler decided not to put a bushing in the pump, which really needs a nice babbitt bushings or a bronze bushing. But they just machine it one-piece so there is no bushing in this pump, which is kind of retarded, but anyway, that’s what they did. So, considering, it is just the aluminum riding on a steel pump gear with using ATF it is it’s lubricity it’s relatively reliable, but not reliable enough.
So again, what we’ve done is we bore the pump out, we put a nice bushing in it, so now we have this bushing that fits inside the pump and all your thrust or all your load relies on this bushing. So it’s like the conventional train again. So we have our bushing, we have our pump gear, and the pump gear rides on the aluminum, or, I’m sorry, the Babbitt bushing, and it rotates, and then you have your compression of oil.
So then we increase oil pressure up to about 270 psi, we don’t have that failure of the aluminum pushing into the steel because you lose your oil barrier and then it wipes out the pump. So now we have a pump that’s sustainable of living into higher pressures for the longevity of, you know, as much as 500,000 miles I guess you should say.
So we made that with the stator, and the stator is another area that is kind of a big deal, because the torque converter that we build has such a high torque multiplication stator on it that I’ll talk about in the torque converter portion coming up, that the stator will twist the stator out of the stator support so we’ve redesigned the stator where it goes into the pump, so we’ve had hardened bolts and a pin support pin that holds the stator, so when it’s all part of the pump assembly that the stator doesn’t twist out of the pump and create a hydraulic loss again and broken stator. So that’s another little modification that’s taken care of in the stator.
And then of course you’ll see a lot of familiarity with the valve body cavity and hydraulic ports. This is all your lockup portion and your pressure regulator system. So the pressure regulator is redesigned to essentially not wear out. The same technology I was talking about in the valve body. And your lockup assembly is redesigned so as its modulated it doesn’t wear out the valve body.
Now, one of the interesting things is because the way Chrysler modulated this lockup control system, the Lockett valve modulates at a frequency that has a tendency kind of wearing out the valve body because of this modulation, so when we add the copilot, we actually take that modulation and we remove it, and we turn the torque converter clutch on over about a 500 millisecond to one second application rate. So it literally turns that valve instead of modulating so much it goes from off to on.
So that in itself the copilot will make your normal transmission or your factory transmission live longer because it is not cycling that lockup valve, because if it cycles at about 60,000 times per second it literally just wears out the oil fitment, wears out the valve body. So some of the stuff in these valve bodies can be controlled, like trying to electronically give you some longevity.
Of course doing the valve modifications, you know, the machine is flat, it takes you have all the hydraulic leaks and then, you know, you add your co-pilot, you get that much more out of it. So there’s a lot going on here, you know.
You have hard parts, you have hydraulics, you have clutch bags, you have electronics, kind of everything together. As we move on to some of the other components. We now get into the Shabs of the transmissions and these are our Shabs that we built, and of course the planetary, and then the overdrive and underdrive clutch assembly. Now when you line these things up, you basically have your shaft that sticks to the torque converter, then this hooks to the clutch drum and then the clutch drums hook to your overdrive hub, and your forward clutch hub hooks to the clutch packs, and then this splines essentially to the planets and then power goes to the rear wheel. So this is going to the rear wheels and this is from the engine.
So what happens when you start clamping all the clutches down so they’re not slipping, you begin to torque on these components so heavily that it breaks the shafts.
So again, we have a billet shaft. I wanted to point out this particular shaft, this is one I just went upstairs and grabbed out. The machine shop doesn’t have splines on it yet because we’re machining that operation the next few days, but this is a piece of 300 mm and the way we machine it, the reason we build a 300mm is because you have your yield, right.
If you go beyond a certain yield, which means when the material doesn’t return back to its neutral shape, then you begin.. it creates stress risers and then it blows up the shaft. Well that happens in the input shaft, it happens in the forward clutch hub and it happens in the overdrive clutch hub, and then ultimately it happens in the output shaft. So we have redesigned or we strengthened all of these components so you don’t have the fatigue and the splitting.In other words, these hubs will break out around the hub, they’ll split down the shaft, I mean they just blow up, they just come apart in every conceivable way. So pretty much in order to make the transmission live, you start having to increase the shaft. So you’ll see our stages as you go from stage 1, stage 2, stage 3, stage 4.
As we start to move up those stages, then we begin to add different components of these shafts. Some of them come just right out of the gate.
For instance, the planetary. These planetaries blow up, the pins come out and wipe it out, which is kind of unique, but again, because the planetary was kind of wimpy the way they built it, you needed a lot of strength. So we’ve redesigned it so we have a complete strength in the system inside, then everything’s tied together. So now these pins are tied together to the carrier, so now they don’t come out, so that’s a huge deal. So you get that with all of our trainees, as far as the back of the trainee, that’s another section. This is a one-way roller clutch that holds power to the transmission in first gear, so manual low and this is hooked to the case, and then this portion is hooked to the load drum, and then of course it’s all put together into an assembly and it freerolls one way and holds the other well.
Your factory Spragg, it’s not a one-way roller clutch, very very wimpy, extremely under-designed, is a Spragg design which is this little guy, this plastic race. So this guy is supposed to handle all the power in manual low or in first gear. So you think about this, you hit a stop light, you have your toy hauler behind you, you accelerate on the throttle, all that power winds up, it goes through the back of this planet, multiplies torque, you’re holding it in the first gear and then this little bitty plastic Spragg has to hold all that power, it doesn’t work, it blows up, so it has to be upgraded.
So we upgrade it to this guy which is basically stronger than the back of the case and it corrects the lower verse or the low roller clutch problem in first gear.
Now there’s a bit of a caveat to this the problem, it is you fix this, then where’s the power go, then it goes in the back of the case, so all that power is held in at the back of the case by the back support, and that means that everything is being held in the back. Well, the problem is once you fix this, then all that power goes to the back of the case if you accelerate too hard, even though cases blow up. So the way we fixed it and the only way to fix it is by using the co-pilot.
The co-pilot actually looks at engine load, and when you go ahead we throttle, we turn these clutches on this big huge clutch pack that ties in directly to the back of the case, this big clutch back is splined to your low reverse hub, right, so now all that power goes through this, directly through these clutches into the big portion of the case with your pan and your case brace. So now this Spragg doesn’t even need to be in the case, it doesn’t even need to be there when you hook the copilot up. All the power goes around this, goes through the clutches and applies 100% of the power through these clutches into the case, and then when you go to second gear, then these clutches are released and the two c’s come on, or the C two’s.
So that’s a, that’s a really cool deal and that’s one of the one of the hidden things about the copilot that a lot of people don’t realize, because the technical aspects of it is we found these things are blowing up and it’s still breaking the cases, so of course, you know, Chrysler D rates the engine well in our mind. Let’s make the training stronger. So by adding the copilot, it utilizes the low E versus clutches that Chrysler doesn’t use, unless you’re in manual low and override the low roller clutch, it gets rid of that condition.
So again, super heavy-duty getting to the kind of the soft parts of the tranny. You’ll see all the clutches here. These are the clutches that we actually upgrade in the tranny, the clutches are probably the least amazing thing about this tranny because our clutch bags, or essentially we’ve selected a clutch bag that we’ve deemed, the best for the application whether it’s a static clutch or just a just a basic dynamic clutch, right. A static clutch kind of holds power like a low roller. It doesn’t have to do much, abuse the dynamic clutches.
Our clutches that you’ll see here and these are.. this our clutch pack for the OverDrive’s.
These guys take a ton of abuse, so how we’ve addressed that is a bigger clutch drum which are overdrive clutch drums, so use the big overdrive clutch drum assembly, replace the thinner clutches with the big clutches, use a coaling steel which allows you a little bit more abuse, because these clutches are sliding a lot, and then, with this bigger clutch drum, this piston is redesigned, so it’s a much bigger hydraulic surface. So there’s about 15% more hydraulic force on this, which means a ton more clamping force, so when you apply this entire thing together and you add all the clutch packs inside here, and then clamp it all down with the nice pressure plate, then this pressure plate clamps everything.
It’s bolted together and it makes it an assembly that is capable of holding lots of power, like lots of power, thousand horsepower.
So I don’t ever recommend a 68 for that kind of power level, but 68 sold really well, you know, over up to about 800 horsepower for the size of it.
I mean, still you’re limited to the size of everything, it’s not like it’s a, you know, massively huge tranny, like an Allison Transmission for instance, because the Allison, for instance, is just bigger, everything’s bigger about it, so inherently, it’s going to hold more power easily.. err, but the 68 does really really well when everything’s redesigned.
So we talked about the case modifications, taking care of that the pan, all the hydraulic modifications, the valve body, the hard part modifications, all the clutch packs you can buy in all of that together and then control it with a nice electronics package, and you have a transmission for its small application behind a huge motor that does really really well. And we’ve had great success with it.
Basically ready. Two different power levels. So hopefully this was helpful.