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700R4 Mods & Tips

Install the Billet 2-4 Servo, It has 35% more apply surface as the Corvette servo. And the servo cushion spring is deleted for a harder 1-2 shift.

Put the .500 or .521 TV boost valve in. This is one of the biggest shift modifiers due to higher line pressure bias. More pressure means exact hard shifts without slippage. Less slippage means less wear and hard apply of the clutches and TCC lockup. This will help save the 3‑4 clutches on WOT shifts. 

Put the hardened pump rings. These are needed when you start running high pressure from you pump. Use your stock springs in the pump if you are using a Syclone 4L60. They are the strongest available 

A Fiber 2-4 band with the anchor pin hole weld reinforced or weld a heavy washer to the anchor hole collar, and drill it out a bit for the pin if needed. Otherwise, the huge 2-4 Servo will rip it by hitting it so hard. Use the fiber 2-4 band if you are using a used reverse clutch drum. Only use a Kevlar band if you what to replace the reverse input clutch drum for a new one. A fiber band will conform to the used drum's grooves where a Kevlar one won't. They both give great apply when they are used properly.

You want Type F fluid for firmer shifts. You will have to change it every 5000-7500 miles though. Trick Shift friction modifiers aren't needed, Trick Shift is Type F dyed blue. Always supplement your fluids with LUBEGUARD. A Few people have had problems with Type F if they haven't rebuilt and used Scotch Brite on the valves to ensure valves are clean and free moving.

Grind the land down on the pressure regulator valve. Two helped, when in 4th gear and the TC unlocks while throttle position starts to drop, the planetary gears get starved for oil. This will increase the flow to the TC lockup clutch for better apply pressure and better flow out of the cooler lines. This will drop line pressure by about 50 lbs. but the bigger .500 or. 521 TV Boost valves more than compensates for this drop.

Planetaries are weak and expensive to replace, the other reason is that it makes noise sometimes when it passes by the valve. You can modify the sun gears to aid planetary lubrication buy cutting a slit in the gear surface that rides against the Torrington bearing, Cut a small slit in the edge 1/16" deep and then cut another slit 180 degrees (basically straight across on the same surface). Do this mod to both sun gears. If you do this modification, be sure to set your end clearance to .005 - .010." A #72 selective washer usually does the trick. This washer is included in the thrust washer kit. If you don't set end clearance to this range, the torrigton bearing may fail.

The TECKPAK Orifice cup plug reducer on the reverse input piston prevents that hesitance when going into reverse after it has sat for a couple of hours. It's called TC drain back.

If you are bending the tangs on your 3-4 clutch apply ring due to high pressure, get a 3-4 clutch apply ring from a 96 and up 4L60E at your Local GM dealer if you don't already have the better apply ring. It will have a "7" stamped on it. Our trannys should already have them, most don't. This Apply Ring is the strongest available. If you want to make it stronger, TIG weld reinforce the 3-4 clutch apply ring with 1/8" plate steel pieces about 2 V.-" long so they just fit inside the fingers. Drill three holes equidistant in the in the middle down the length. TIG weld at these holes, the greater pressure will cause this ring to balloon out in the middle of the flanges.

Make sure to machine and mic the pump and vanes if they need it for better tolerance and higher pressure. Check to make sure your faces are flat. Check this by using a straight edge and running it over the complete surface of the pump body and the stator body. Flat file it if it isn't flat.

Check the face for flatness. Do the same thing as the pump if it isn't truly flat. 

Seal the 3-4 bleed hole on the input drum. They leak too much and it causes the 3-4 clutch pack to bum up sometimes. It's better to just weld, epoxy it shut. I use JB Weld. No more mysterious 3-4 clutch-pack burn‑ups.

Always use the solid Teflon seals on the stator shaft instead of the standard scarf cut seals. '93 4L60's and up should already use them so replace them with the same. The solid seals will hold up to the pressure better and allow for more consistent shift characteristics.

Scotch Brite all servo and accumulator bores.

When you have the reverse clutch drum out, look to see that the area the 2-4 band rides on is shiny and smooth. 400 grit sand paper will help this if needed. Adjust the band to 1/ 16" to 1/8" for the best clearance. Check this by assembling the servo and putting the cover on without the seal at first. Now press in on the cover and check the travel by measuring the clearance between the cover and the snap ring with a feeler gauge. Once you got it correctly pull it out and put on the seals and reassemble.

Get a Derale tranny pan. It offers the best cooling. Always concentrate on cooling. Better cooling means longer tranny life and better shifts.

Also go with an external STACKED PLATE tranny cooler. Larger (GVW) the better with fan.

If you are having problems with the 3-4 Shift at WOT don't let them write it off as a valve body so quickly. You may need different springs in your governor or the Fairbank's designed up shift sleeve that we should have already but inconsistencies at the factory might have deleted this option on accident. These sleeves are available from many companies for ~ $30.00

After you have your cooling taken care of, put in a remote tranny filter kit from SUMMIT. Model number SUM‑G4980. It only costs $26.69. This filter is better then the regular filter configuration and is used in addition. This kit also provides a nice threaded location for a Tranny temp sender for the gauge you should have.

You don't need to get a shift kit (if you have a Syclone or Typhoon) because our tranny comes with the stiffest springs available, many kits are even softer than our stock configuration. The modifications above are all that is needed for the strongest and crispest shifts possible. If you were building up a Corvette or lesser tranny and didn't want to take the time to piece meal one together, then a Trans Go shift kit might be a good alternative.

Also get a custom 2650-2900 stall lockup Torque Converter if you are running close to stock SyTy specs. You'll need to consider a different stall if you are either modified or a different automobile. The 9/11" lockup TC's are good. PI's are alright too.

Note. If using Dextron 3, you can supplement your fluid with 30 weight motor oil at 20% total volume or 4:1 to help lube the seals. It won't hurt the tranny. I use Synthetic with Lube guard additive exclusively. I suggest you use Mobil I Synthetic or equivalent. Type F sometimes sticks valves in a few VB's and there isn't anything you can do about it except revert back to Synths.

For a chattering TC lockup clutch, get some Limited Slip fluid from GM used to keep the limited slip differentials from chattering and popping.

You will want to flip and block the 1-2 and the 3-4 accumulators. This is for firmer shifts in all gears due to no give in the accumulators via the piston springs. If you are using the .521 TV Boost valve, leave the 1-2 accumulator as is. Your 1-2 shift assembly needs a little give when using the high pressure of the .521 TV Boost Valve.

Delete 3-4 load release spring assemblies for better 2-3 shifts and better 3-4 clutch durability.

NOTE: If you have one of the TCS 9/11 Lock ups, you can delete the check ball and retainer for very positive lockups. It feels like a whole new gear hitting.

Drill the oil return line orifice out to 9/32 or 5/16 in both halves of the pump to ease oil pressure behind front pump seal.


I have a tip on removing the pump easier. Use a pair of vise-grips and attach them to the stator shaft. Take a gear puller and index it on a penny on the end of the input shaft. Either you can use a couple of large washers that you would drop onto the shaft before attaching the vise-grips, which then you bring up to butt up against the Vise-grips or just attach the pulley puller jaws to the vise grips. As to start pulling just put a large screw driver into the inspection window (no need to remove the linkage) and lightly pry the reverse drum down. It will fall loose as the pump lifts out of the tranny. This works great and saves a lot of headache.

I found that most of the bushings can be removed by slitting them carefully w/ a Dremel tool w/ a small round bur chucked, then peel' em out w/ a screwdriver or just tap gently - just don't screw up the bore they go in.  Hacksaw will work, too, if you're *real* careful.  A bushing installer tool can be made from various bolts, washers & nuts; get a good selection from local hardware store.  Some wood plugs to fit inside the bushings & center the bolt in the bore are easily made w/ a hole saw. The plugs are to prevent the bolt from cocking in the bore, as they readily do.

You can get it tanked but you still need to clean the solvent really good.  I take it to the car wash and degrease it and blow out all the fluid. I then clean up the case with a wire brush until it's shiny and polish it up to a nice reflective smooth finish. I then go over it with Brake Kleen. That's what I use to do the final cleaning on parts before I put them in. Use about 9cans per tranny.

Here's a tip to keep you safe. Go get a couple of cargo straps with the buckles (not the ratchets) and make a cradle or safety net.  Hook the strap into the frame, then up over the torsion bar, then under the tranny, then up over the next torsion bar, then hook to the frame.  Put them on as you get close to being ready to drop it down.  It also helps when you put it back up.

Matt H
Robert P
Les Y
Tony M
Jeff D
Nolan N
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Mark L
John W
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