Here it is two weeks later, and my DIY rebuild of my 4R70W is complete. Not that it took two full weeks to do it (actually, the entire process was more like 8 hours, and even that is probably 2-3 times longer than it would take somebody who knew what they were doing to do it.)
I'm here to tell you that while it isn't that hard to rebuild one, the proper tools, or lack thereof is what makes it impossible for average joe to do.
I converted this trans to full manual, w/ an electronically activated OD, and Lock up of the converter. That requires the installation of a transgo kit. The valve body part is typical if you've ever installed a shift kit before, but to give the transmission it's full manual capability involves replacing the electronically controlled EPC solenoid w/ an old school vacuum modulator. That also required drilling the case for the vacuum barb that acts as a pass through for the vacuum line to that modulator.
There is one small problem w/ using a vacuum modulator to control the line pressure that will allow me to manually shift the thing though, and that is the turbocharger. Vacuum will cease almost immediately in this combination, and the diaphragm in a vacuum modulator will cease to exist equally quick once boost is applied. There are two solutions to the problem, one of which I am unsure of.
1. Use a Transgo sourced vacuum bypass kit. (a glorified check ball in a tee w/ a spring out of a Bic Click to shut off boost pressure to the modulator, and vent it to atmosphere.
(in my mind, this creates a boost signal leak)
2. Tee the vacuum reference from the intake of the turbo.
( This is the one I'm unsure of,..is the vacuum signal in front of the impeller the same as intake manifold vacuum?)
Anyway, I digress.
The only real tool to take the transmission apart is a homemade bridge to span the servo covers w/ a bolt threaded through it to compress the servo pistons enough to get the snap ring out. That and a slide hammer to pull the front pump. I made the tool, and had a cheapo slide hammer and in about 30 minutes the whole thing was apart and on my bench.
The valvebody mods were next,..... again typical if you've ever did a shift kit before.
Getting the clutches replaced in the three clutch drums was a little more difficult. Fortunately I have a guy at Mr. Transmission, and leaving the three drums w/ him for a couple of hours netted me three drums w/ new Alto red clutches installed when I came to pick them up.
Net cost= 0$
Old sealing rings used what was/is called a scarf cut seal. Simply stated, its just a diagonal slice to allow you to spread the ring enough to get it over the shaft, and into the groove. New sealing rings are solid, and made of teflon. They require yet another tool to install them, and then compress them after installation. (which I don't have as well) That required another trip to yet another trans shop down the road where the guy stops what he's doing, and installs my 4 sealing rings for me while I stood there.
The "special tool" he had was knowledge in the end, he simply used a pick to stretch the rings over and into their respective grooves. Once they're stretched they need a tool to compress them to their final shape. On one set of rings, he used that tool. On the other he used two standard fuel line clamps, and sent me home with them clamping the rings. "Take the clamps off when you get home, and you'll be good".
Net cost=0$
Once back home w/ everything in hand, I start the process of assembling the trans. This should've take about an hour.
Remember however, we're talking about me."Do it twice Mike" is what my friends call me.
Apparently for good reason.
The trans assembles like a tower. Stood up on end each sub assembly stacks on top of each other until you reach the top of the tower where you cap it off with the pump.
Round one had me at the top when I remember that I wanted to ck clutch pack clearances.
I pull the stuff back out. I measure clearances.I build the tower again.
Reading the assembly guide, I become aware that in order to properly guide the servo pins onto their respective bands, you should install each servo at the stage of each band install.
One of those bands is now three assemblies buried in the tower.
I pull it back apart. Install the OD servo, and start to build the tower again.
Completely assembled, this trans is a heavy pig. Each sub assembly is heavy in it's own right. Some of those assemblies are merged together with other assemblies w/ nothing but gravity holding them together until the whole thing is bolted back together. I was lowering one of the assemblies into the case when, as I moved it from the bench to the trans, one of those "merged assemblies" came unmerged, and hit the floor.
What followed next was another slow motion moment for me, as I watched 15 lbs of planetary gear set w/ a one way sprag attached fall to the floor and promptly explode across the garage floor. 13 roller bearings scatter to the four corners of the room.
NOOOOOOO!!!!FFFFFUUUUUUUCCCCCCKKKKKK!!!
I spent the next hour crawling around the floor looking for those stinking bearings.
Once I find them all, I reassemble the sprag, attach it to the gearset, and reinstall the assembly into the trans. The rest of the build moves along w/o incident.
All through the whole build, there is reference to a little tubular screen that was supposed to be in the case. Mine didn't have it. There was a hole where the screen was supposed to go, but I had no screen. I simply figured that my version must not have had one. I put it together w/ out one.
I'm putting on the pan, and I notice this little bag laying on the floor. Inside that little bag is this little tubular screen.
Go figure.
I take the pan off, remove the filter, unbolt the 20 some odd bolts that hold the valve body in place, remove that, and stick that little stupid screen where its' supposed to go.
Put the valve body back in place, bolt the pan on, and just as I'm tightening the last bolt, finally done w/ this b itch once and for all, I notice the filter is still laying on the bench.
