4L60E Build
Question 2: I'm a dumb Dora. I heated the pump half up to 550F for 40 minutes than dropped that stator in on my failed attempt. It fell right in no problem but I let it cool off suspended on two 2x4 pieces of wood. Well, some of that cellulose / wood burnt into the metal. I have been using a gray buffing pad (3m scotch bright light pad). Very gently polishing it off. It's taking forever and a day. I've also checked for flat again. It's flat as a pancake. I'm **** retentive though, I called a machine shop to see about simply planning that pump half. They were baffled when I said 4L60E *sigh*. I presume the pump should be fine even with that burnt wood residue / film on there? I also tried paint thinner on there... Not sure if something could soak that off, without harming the aluminum? Paint thinner had no effect.
Regarding the film on the pump half, take scotchbrite and scuff if off. It should come off. There is another method but the green scotchbrite should do the trick
New question, good flat surface to sand for pump rotor? Or leave be? It turns freely but has less than 0.0015" clerance
I watched several tutorials on building the pump. I also have the ATSG manual which basically just check the rotor moves freely. I torqued my case halves to spec and checked this. It does spin freely. However, Dana at Pro Built Automatics specs this way... He says there should be 0.002" to 0.003" clearance for pump rotor HERE. I have less than 0.0015" - my smallest feeler 0.0015" won't fit but light does pass through when I use a flashlight to look under the flat edge.
Long story short, the linked procedure recommends sanding the rotor down with 400 grit to obtain 2tho to 3tho clearance. I don't have a flat granite slab though. Flattest surface I have is the granite in my kitchen. One corner of my island is to within less than 0.0015". Would it be prudent to knock a little off the rotor?
Otherwise maybe I could have a machine shop flatten a piece of steel for me. I see calibrated flat granite is like $500+
Last edited by weinerschizel; Oct 6, 2021 at 02:06 PM.
you could probably take a fine sharpening stone and go over the pump half. put the old stator back in and call it.
edit: as far as pump depth, i tried flat sanding on a piece of 3/4" glass when I did my first 700 10 years ago. was out .001". Ended up taking to a machine shop and gave them the slide, rotor and pump half and told them what I wanted. you can then check it with a straight edge and feeler to see where its at.
The Best V8 Stories One Small Block at Time
I polished my connecting rods for my engine build... but I used the flat deck on my scrap engine block. I should have kept the block as it worked like a champ although was a bit cumbersome.
The green scotch bright worked great for pump case. I lightly buffed for about 30 minutes then switched to to a gray one. Stayed flat as a pancake but really cleaned the surface up. Great advice you really are experienced
Last edited by weinerschizel; Oct 6, 2021 at 10:06 PM.

I have not seen anyone prep and polish Connecting-Rods in 25+ Years.
It is not worth the time and effort anymore, when cheap Chinese Rods (that actually work fine) have flooded the market.
Those look like oil squirters too... Did you modify them to have the chamfer? What are the wholes at top of wrist pin area?
But they are Grooves in the Big-End that direct some of the Oil that gets sprayed-out towards the underside of the Piston.
This will cool the Pistons down some, like actual Oil-Squirters do (just not as well).
You are seeing one of the lubrication Holes in the Small-End...
They are used with "Floating" Wrist-Pins, in order to cool and lubricate the Rod and Wrist-Pin surfaces that rub together.
There will also be a thin Bushing in the Small-End (sometimes with Grooves for the Oil to spread).

Curious do you prefer to run on the low, middle, or high side of the tolerances for the clutch packs?
The update to that book retracts that and recommends using them. I feel like if they werent needed, GM wouldnt have put them in there. I ALWAYS put them in. I have had many units come to me that were previously rebuilt and the 3-4 was burned up. Many of them had the springs left out from previous builders. Coincidence maybe. But If it cost GM .25 to put them in each unit, and they built over a million units (probably more than that) then they lost $250k putting them in. Honestly, if they werent needed, in all of the updates that trans has had over the years, they would have left them out. think about that.
I run .035 to .045 3-4 clearance. Thats what works for me. I havent had a 3-4 burn up in probably at least 10 years
The other set of Springs holds the Clutch Backing Plate up off of the Clutches.
These two sets of Springs are pushing in opposite directions.
There is no harm in using the stiffer Piston Return Springs with the Backing Plate Lift Springs.
some think the outer set of springs is pushing the apply plate off the clutches (after all...the backing plate is fixed against the snap ring)
so they would be pushing in the same direction.
Regardless...doesn't matter...the idea of the outer springs is to ensure the clutch stack has forced separation to reduce drag.
This is beneficial in my opinion.
Not NECESSARY by any means...so the guys that say "I ran no springs for 20 years and no issues" are probably telling the truth. You don't need them.
But...it doesn't hurt a thing and when spinning 5500+ rpm the reduced drag is nice










