Just to recap to this point, in 3 previous threads I have:

1) Torn down a 1990 C4 Vette transmission.
2) Completely disassembled it, and inspected each and every part.
3) Built up the "Back Half", or output side of the transmission.
4) Rebuilt the input drum.
5) Rebuilt the reverse drum, and installed the guts in a brand new drum to facilitate the wider band I intend to run.
6) Rebuilt the Governor.
7) Rebuilt the servo assembly.
8) Installed the tailhousing and speedo gear (driven)

I wanted to cover the pump next. The pump is a vane style, and contains a rotor and vanes that spin with every revolution of the motor. The pump produces maximum pressure, and is regulated by a bypass valve to limit pressure on the low side. The boost valve controls pressure on the high side. Lo-Rev boost valve controls pressure to the lo-reverse clutch pack.

Below is the 2 pump halves disassembled, and cleaned up for inspection. A straight edge and feeler guage reveal they are dead balls flat, as expected. The center areas that are scarred up are not as bad as the pics make them appear. A certain amount of wear here is typical, and this one(in my opinion) is acceptable. There is less than .0015 depressions in the pump, but as I said, the pics make them look worse than they really are.







Once bare and cleaned, I install the teflon lined bushing first. I like the teflon bushings, and I secure them with locktite. Because this one has been replaced more than once, I use green sleeve retainer for extra security.





The bushing is driven in carefully, to a depth specific to a very small, machined ridge in the pump bore. I had a machinist friend make the driver below for me. It cannot over drive the bushing, and snap the delicate lip.





Next, I stake the bushing, and deburr the sides.




I clean the residual locktite, as ATF and locktite do not play well together.
At this point, the front pump seal is ready to be installed. Although there are special drivers for this, a block of wood and a hammer work fine.



Then the front seal retainer is installed.





At this point, I decide that the pump core that is "acceptable" is not. I have come this far, and want this trans to be perfect in every way, so I call a place in Tennessee that sells used trans parts, and he is shipping me a hand picked core that is near perfect. I shall repeat the process on that one once it arrives, an continue the pump build up at that time.
God, I am too damn fussy sometimes.

While I wait for my used pump core to arrive, I can rebuild some of the other parts.

Tha aux valve body is small, and easy. It is used to cushion the blow to the driveline when shifting to drive, or when banging gears back and forth between reverse and drive, such as when stuck in the snow or mud. Basically, another accumulator in the trans.

In mid 87, GM used a cast iron end cover, instead of the typical aluminum. I had one laying around, so I will use it on the 1990 aux valve body.
Photo below shows the difference.




The next pic shows the completely disassembled aux vb. I always replace the accumulator piston and seal, as they tend to wear in the center hole.




The aux valve body is spitshined in and out, new piston installed, and reassembled.

Incredible Job Pete !!

I'm following every step.... I only wish this was done a year ago before I bought my 700R4.... I would have attempted the rebuild myself. I've always stayed clear of transmissions out of fear....

I think when done, this might be the best transmission technical thread ever done on the Internet.....

Keep going, I'm paying attention.

Quote:

Thanks!
I am trying hard to walk the line between being way too specific (boring), but not leave out anything important. Most guys get bored if it drags out for 10 pages or more. After it is complete, I may add some more pics and details so it could be most helpful to someone that wishes to build one up from scratch.

In my opinion, this thread has long-lasting implications. You're probably not going to get a lot of people to follow it word for word as you do it..... that is until they need it, then they'll go back and read it word for word while their transmission in on their work bench.

I would suggest, that when you are done, combine all build-up chapters to just one long thread and put it up top as a long-standing sticky. I'm pretty sure that this tech article will prove to be an incredible resource for the latemodels for many years to come.

Moving forward, I rebuilt the valve body, and made the nescessary mods to the separator plate for some custom tweaking, and for the requirements of the B&M Shift Kit.

Pic below is the reassembled valve body.



This is the view most are familiar with, when they drop the pan, and look up.
The valve body is responsible for opening and closing valves to allow fluid pressure to activate a clutchpack or band. Small holes in valve body are fluid dumps. After a given valve does it's thing, it must blow off the pressure.


The pic below shows the worm track on the top of the valve body. When a valve opens or closes, fluid travels the path, and then goes through the seperator plate that is between the valve body, and the main transmission case.




If you look closely, I have retained the required checkballs in their correct spot using vaseline. Shop manual and/or shift kit determines their location for a given model year. There are 3 styles of valve bodies for the 700r4/4L60:


82-87 (non aux valve body units)
87-92 (aux valve body units)
1993 - *specific to this year only

It is critical to properly disassemble, and clean the valve body. When a trans wears and fails, the valvebody becomes filled with trash. The trash must be cleaned, as a fleck of dirt the size of pepper can block up a valve.

I normally disassemble and lay everything out like the photo below:




I then block out the machined side of the valve body gently with a fine stone, to knock off the slight burrs only. The purpose is only to dress the surface, not change it.

Then, I use a couple of cans of good carb cleaner to get it clean. I then use brake cleaner, followed by a soap and water bath., then completely air dry the casting.


Next, each and every valve is inspected with a magnifying glass, and by feel for any minute burr.
If I find one, I use a small piece of gray scrubby pad to knock the burr off.
Then each and every valve, spring or sleeve is cleaned with carb cleaner, blown dry, and installed into the Valve Body one at a time, using only ATF as lube.
Once completely assembled, I place the checkballs in as per the shop manual/shift kit manufacturer.

If you look carefully at the pic below, you will see the 2 checkballs installed and retained with a blob of vaseline. If I were installing in a pre 87, the "bathtub" would receive a checkball as well. This is a 90, so no bathtub checkball.




The pic below shows the shifter selector shaft. When you shift gears, this valve moves, and directs fluid through the center of it accordingly:




Pic below shows the plunger for the tv valve. This valve is the heart of the trans, so I always check it 2x or more.



The shifter plate below is modded as per the shift kit manufacturer, and the builder based on his oiling modification preference. This plate is installed between the valve body and the case, sep3rating each worm track, and providing orifices to control fluid pressures and volumes. Think of the worm tracks as Plenum's and the plate orifice as the throttle body, or venturi.

The size of the valves, and springs in the valve body establish the "character" of a trans. You would not want to install a Cadillac valve body in a vette, or vice-versa. This is one of the reasons why I think remanufacturing your oem trans is best.
Most shops do not understand the differences. I have learned to identify each valve and spring combo, and replicate it for a given transmission. A trans you buy off e-bay or another mass builder will not address these minor differences. You simply "you get what you get".

Finally finished assembling it last night. I will load the pics, and try to do a summary in the near future.

Thanks!

Quote:...THanks Pete....

When are you going to finish the thread?


Mike

Quote:
Mike,
I did intend to do it this past week, but had to travel for work. I shall get some of it done tonight. Thanks for the reminder. Truthfully, I did not think there was a whole lot of interest, but I am glad to see there is.

Can't wait to see it!

I am going to back up a bit. If you recall, I decided to redo the pump with a better core. I had not assembled completely the pump castings, so I will do that now.

As you can see from the 2 pics below, the pump rotor wear surface is near perfect. They appear to have slight wear, but I cannot measure it because it is so minor. It cannot be felt, and a light scuff with very fine emery paper has cleaned up the staining. I am very please with this core.







After inspecting and spitshining, I pressed in a new teflon bushing, and extra wide busings into the stator. New front seal, and a retaining clip are again installed.

Pic below shows the old worn stator shaft against a brand new one.




Next pic shows 1 pc stator rings from a 4L60E being retrofit to the 90 stator. Special expander is used to get them on



And the pick below shows the shrinking sleeve. Same principle as the sealing rings on the input shaft.I leave the shrinker on for a minimum of 12 hours.



Next is the assembled front pump half. New pump vanes, new hardened rings, and a high rpm slide spring complete this 1/2




Finally, all valves and springs, along with a filter are installed into the pump body, and it is complete




I forgot to snap a pic of the marriage of the 2 halves. Basically, they are fitted together, and a large hose clamp goes around the perimeter, to jig them up perfectlt straight with each other. Then the 5 bolts are installed, and torqued to 18 ft lbs.
Once that is done, I remove the hose clamp, and dry fit the pump into the near empty case to assure a slip fit. I do not install the large pump o-ring at this time.




It fits like a glove, so I remove it, and set it on the bench with the input drum, reverse input drum, and band (that is soaking in atf).

Check build #5 for final assembly.