Corvette servo

Post by **HenryJ** » Sun Apr 18, 2004 6:57 am

Ran across some info on the mod- Corvette servo- 4L60E all years , Installation instructions

Tranny Upgrade Part I (Corvette Servo)

Transgo Servo Upgrade

Post by **HenryJ** » Sun May 09, 2004 8:27 am

I could not resist so I am going to try it-

KDS Corvette Servo
Total with shipping- $21.95

# 700R4/4L60/4L60E
# Bring even more shifting power out of ANY shift kit or use by itself!!
# Can be installed easily with transmission in vehicle.
# Firms up 1-2 shift
# Increases line pressure for extra band holding power.
# Works great with any year of 700R4 or 4L60E.
# Includes all necessary gaskets, O-rings for installation. Not included with most other servo kits but are required for installation.
# Servo installs easily - pull out servo cover on passenger side. Cut O-ring and remove this allows cover to pull completely out, dissassemble servo assembly, replace servo assembly.

A little firmer 1-2 shift would be nice and the extra band holding power can't hurt.

What the heck it is a fairly cheap mod, I'll give it a try.

Conman · Post by **Conman** » Sun May 09, 2004 10:00 am

Interesting mod. What does this part do? Increases line pressure or something else? Auto Trans are a mistery to me.

Cheers,
Con

Post by **HenryJ** » Sun May 09, 2004 1:12 pm

YDM (Corvette) is on the left and the F-body on the right. Notice the substantial difference in size. The larger piston allows for more holding power.

jarhead · Post by **jarhead** » Mon May 10, 2004 12:44 pm

Whats up HenryJ have you installed it yet?

Post by **HenryJ** » Mon May 10, 2004 1:40 pm

jarhead wrote:Whats up HenryJ have you installed it yet?

it will be a couple weeks, the parts have not arrived yet

Post by **HenryJ** » Mon May 17, 2004 4:00 pm

Ok, so the parts arrived and I just finished installing them.

First off the install was a real pain due to the fact that the darn pre-cat is right in the way!
If not for that the install would have been pretty easy.

Pulling the cover did require cutting the o-ring , slipping it out, then the cover came right out easily.

There were no instructions with the parts, and the links above were not very clear, IMO. Best to pay close attention to how things come apart and re-assemble the same. I did print out and carefully read this set of instructions- Tranny Upgrade Part I (Corvette Servo)

I , carefully, used the base of the O2 sensor as a point to pry the cap in for removal of the c-clip. It does not take much pressure and as I explained before that darn pre-cat is in the way for any other method.
The blue o-ring is for the cover. The teflon seals both go on the 2nd apply piston (one large , one small) , the red o-ring goes on the servo piston housing (inner). Pay close attention and put the inner most spring back over the center nub after you "gut" the servo.

Most of that last paragraph will make sense when you do this mod

The parts replaced were not as differing in size as the pictures in the above linked instructions, leading me to believe that the improvement may be less than would otherwise have been.

I lost about three tablespoons of fluid during the process. Not enough to warrant adding fluid

Total time for the install, including clean-up ,was probably thirty minutes to an hour.

I have a 2" BL , and that made a difficult install easier, not sure if I'd attempt it without the extra room.

I have not driven it enough to feel how much difference it made at this point.

Post by **HenryJ** » Wed May 19, 2004 3:24 pm

Well, it has been long enough to say that I am pleased with the difference.

It is about the same difference that the HPPIII shift firmness made from stock. Not a huge difference but just a little firmer. I only wish that all the shifts were this good

It just feels right.

I don't think it would bark/chirp the tires on dry pavement at WOT , when it is a little wet out, you never know?

I found a "sticky" on the S-series Forum- Installing the corvette servo. There are some good pictures and a nice write-up.

Rusty · Post by **Rusty** » Tue Jun 15, 2004 7:43 am

Anyone else get this? I just ordered mine. Now I just need to clear a spot in the garage to do the install.

Rusty · Post by **Rusty** » Tue Jun 22, 2004 9:36 am

Hey Brule. Just got my servo "kit". It comes with the servo, a red O ring and a blue O ring and (big surprise) no instructions. I can probably figure out most of it but which O ring is which? Do I need anything else, other than the Beer stocked refrig and tools? (at least I have A/C in my garage now) I looked at the one website but it didn't mention anything about the colors and I noticed there is a very slight size difference between the two.

Rusty · Post by **Rusty** » Tue Jun 22, 2004 10:25 am

Never mind. Found it. Man, I need to get these glasses checked!

Post by **HenryJ** » Tue Jun 22, 2004 12:24 pm

Good luck, and keep the little ones ears closed and out of wrench throwing range, for most of the disassembly (#&*#@%)

Rusty · Post by **Rusty** » Tue Jun 22, 2004 1:03 pm

HenryJ wrote:Good luck, and keep the little ones ears closed and out of wrench throwing range, for most of the disassembly (#&*#@%)

It's kinda funny but I pulled the truck into the garage (I've stuffed the Blazer into the corner for a while) and crawled under to take a look. Then I pulled it right back out of the garage, closed the door and tossed the servo kit into the top of my tool box. Ain't no way I'm messing with that one anytime soon. I don't have a body lift and I only needed one look to tell me installing it was going to be a nightmare. What I'll probably have to do is drop the Y pipe (or at least loosen it and move it) and unhook the tranny mount and shove the tranny over to gain the needed room to get at the servo. Without a body lift it seems likely I won't have enough space between the floor/transmission hump and the servo cover to even get the cover off.

This does have me thinking about a body lift too. Might be less work!

Post by **HenryJ** » Tue Jun 22, 2004 1:12 pm

Ahh ... the many advantages of a body lift

You'd probably have to drop the tranny down to get the assembly out with out the BL?

That darn pre-cat is right in the wrong spot too

I wish mine had plugged up before the servo install, it would be much easier now

Rusty · Post by **Rusty** » Tue Jun 22, 2004 1:49 pm

One thought I just had would be to take out the body mount bolts on the passenger side and jack up the body slightly, maybe 3-4". Think that might work?

Post by **HenryJ** » Tue Jun 22, 2004 2:09 pm

GaryH wrote:One thought I just had would be to take out the body mount bolts on the passenger side and jack up the body slightly, maybe 3-4". Think that might work?

3" maybe carefully watching the PCM harness, front axle actuator cable, battery cable. You'd have to be careful to disconnect the tranny lines/wiring from the clamp on the side of the oil pan , the ground strap on the firewall , and take the fan shroud loose so that you do not break anything.

It could be done though.

You might download the PA BL instructions from the mod page and study all the pitfalls of raising the body. Usually the left side is lifted first to avoid complications that exist on the right side.

Rusty · Post by **Rusty** » Tue Jun 22, 2004 4:56 pm

HenryJ wrote:Usually the left side is lifted first to avoid complications that exist on the right side.

And, of course, it's the right side I need to work on. Any way we look at it, installing this servo kit on a non-lifted S-10 is a major pain in the caboose.

Oh well, it'll make a nice paper weight for my work bench!

Post by **HenryJ** » Sun Oct 23, 2005 8:23 am

This one has worked really well. Now that I am running bigger tires, and pulling a trailer, I began to look into other modifications that would help the transmission life a little more.

The 4th gear servo and longer pin came into focus.

Oregon Performance Transmissions wrote:...This servo pin will help you get your band adjusted to the right clearance. It's almost more important to get the right clearance as it is to change to the Corvette servo. If you push in on your servo cover, you'll notice that it moves in around 1/8"-1/4". This is way too much travel; it should be closer to 1/16". This pin reduces the servo travel down so you'll be in the right range. This is a must for any performance, towing, RV/off-road application, but would be a nice upgrade for any 700R4 or 4L60E. Since the servo isn't traveling as far before it applies the band, the 1-2 and 3-4 shift will be quicker and will not allow the servo to go beyond it's travel inside the servo bore.

Oregon Performance Transmissions wrote:...While the Corvette servo replaces the two inner pistons, this replaces the outer piston and cover, so this can be used together with the Corvette servo for ultimate performance. This servo increases the holding power in overdrive by 40%, to almost completely eliminate the chance of burning up the band. While using this servo you'll be able to pull most loads and even race in overdrive without burning up the band.

Keep in mind that these are simple , no transmission removal, additions. A shift kit is a different thing alltogether. While I may add a shift kit at some point , these are just performance parts that would be a good addition to that , or any transmission. When I get to the point of a shift kit, I will do a complete rebuild including a beefy sun shell, and other improvements.

These two additions could have been added at the same time the corvette servo was added and probably at a discount.

I am still waiting on questions to be answered by Oregon Performance Transmission before I commit to this addition.

ludwis · Post by **ludwis** » Sun Oct 23, 2005 8:29 am

Do you have to remove the HPPIII shift firmness setting after performing any of these mods?

Post by **HenryJ** » Sun Oct 23, 2005 8:37 am

No, I have been running the corvette servo and shift firmness.

The length of the pin reduces the freeplay and increases pressure on the band. The pistons require less fluid for activation, and have more surface area.

The HPPIII increases line pressure.

All of them help to reduce slippage and should work to increase transmission life.

"If these are good things , then why don't they came with them?" Cost? Perhaps more likely that the average soccer grandma that these were marketed to won't like a firm shift. She wants to float down the road never feeling the transition during a shift change. There are no worries of failure since she rarely travels further than the market on Saturday and bingo on Sunday, with no more load than Marge and her groceries.

I however treat my truck a little differently and like a quick firm shift

EDIT:
After an email from Oregon Performance Transmission, I decided to give them a try. I ordered the 4L60E BILLET 4TH SUPERIOR SUPER SERVO and the 4L60E LONG SERVO PIN

Here is their new website- OPT Oregon Performance Transmission

Post by **HenryJ** » Thu Oct 27, 2005 3:47 pm

Parts arrived today. Not too bad at five days from order to received.

The Billet servo looks pretty good. Made by Shift technology products , a division of Superior Transmission parts Inc.

The longer pin is an AC Delco part. Here is your chance to save a little

The AC Delco number is : 8680501
I found it on GM parts Direct nearly five dollars cheaper than what I paid.

GM PART # 8680501
CATEGORY: All
PACK QTY: 1
GM LIST: $19.81
OUR PRICE: $11.28
DESCRIPTION: PIN

I'll let you know how the install goes. I have a few days off and plan to install them soon.

Post by **HenryJ** » Fri Oct 28, 2005 12:30 pm

The install went pretty good. As before only a few tablespoons of fluid is lost.

To remove the cover, cutting the o-ring is the easiest way to remove the cover as I found out the first time.

Here are all the parts-

You can see that the new billet 4th servo is about a 1/4" inch larger in diameter than the stock one and in addition to a better designed seal the clearances are closer as well.

There is not much difference in the pins.

The new one is just about 1/8" longer at the point.

Assembly is pretty straight forward. Be careful of the inner seal on the 4th servo and push it into the cover. take the C-clip off of the old pin , swap pins and the new spring.

Before sliding this all back up into place, check to make sure that the inner spring is still in place and has not fallen down-

The whole process took about 40 minutes including clean-up.

It probably could be done faster, but I had a little trouble getting the C-ring retaining clip fully seated. The new cover will only depress 1/8" now due to the longer pin. This makes it harder to get the retaining C-ring fully seated. You have to push / pry in on the center of the cover while trying to insert the ring. PITA. A slight bevel on the cover might have helped matters, but I got it eventually. Remember that once you push the cover past the retaining ring groove, you are committed to install it. Removing the cover again will likely require cutting its o-ring.
Make darn sure it is seated fully. You would not want this popping out while driving down the road.

I took it for a "run around the block". I LIKE IT! It got rid of the little "search" I had around 35-40 mph. After installing the 33" tires there was this mushy spot around 35-40 mph. It is gone now. Nice positive shifts and 3-4th is raised slightly at moderate acceleration. It now shifts 2-3 35 mph, 3-4 45 mph and the converter locks at 50-55 mph.
Before it was like it was trying to shift and lock the converter at 40 mph. I think that is what the mushy feeling might have been.

It just feels right now

Post by **HenryJ** » Sat Oct 29, 2005 5:25 pm

I realize that I just quoted this article in another thread, but there is a part that is relavant to the servo mods here-

4L60E - TRANSMISSION

"Advisory Tip Sheet"

This information is provided for the non-transmission mechanic to help them identify the problem, know how much the job should cost and how to have the problem corrected. This information could save you hundreds even a thousand dollars or more.

This transmission has been in use since 1993 and is a fully electronic unit, but it shares many of the internal parts with the earlier non-electronic 700R4 / 4L60 version, witch’s been in use since 1982. This means most of the internal parts can be bought at a reasonable price.

Never allow a repair shop to give you a price on this transmission that isn’t a guaranteed price. This means don’t get a price plus hard parts. They know about what the parts will cost. The only part that should be extra is the transmission case, if it’s bad. GET THE PRICE BEFORE THE TRANSMISSION IS REMOVED FROM THE CAR OR TRUCK! If they can’t give you a price up front, you’re at the wrong shop.

When you have a problem with your transmission always check the fluid level and condition first. The fluid should be red, not dark brown or black. Smell the fluid to see if it smells like oil or has a burnt smell. If the fluid looks and smells good then the electronic parts should be diagnosed with an electronic scanner to see if any trouble codes are present. Sometimes the problem can be corrected by changing a sensor or solenoid without removing the transmission from the car.

Look in the transmission oil pan for debris (trash) from a clutch or metal part failure. If the fluid is black, smells burnt or has a large amount of debris in the pan, you’ve got a problem. The transmission will have to be removed and rebuilt. Always install a new torque converter when the transmission is rebuilt. Never try to save money by reusing a torque converter that is full of debris from a failed transmission. The 4L60E converter also has a clutch in it that could be bad.

When you have your 4L60E transmission rebuilt it’s always better to get your original transmission back. Because the 4L60E comes in everything from the S-10 pickup to the much larger Suburban. If you get the wrong 4L60E in your car or truck, the transmission won’t work correctly or last vary long. The calibrations are different for each type car or truck.

Place the transmission in drive position, when towing a trailer, not overdrive position. This transmission will only tow a light trailer and last. The 4L60E didn’t come in a one ton truck, because it isn’t strong enough for a one ton truck. If you need a one ton get one. Don’t tow a trailer that is too heavy for your car or truck.

There is no need for a shift kit in this transmission, because you can get better results by installing a larger servo or even a high performance servo. You can also install extra 3-4 clutches and other upgrades for an extra charge when it is rebuilt. The servo can be added at anytime without removing the transmission.

If you have a problem with the front seal, installing a new seal is a waste of time and money, it will only leak or blow off again. You must install a new seal, torque converter and rebuild the pump all at the same time to correct this front seal leak. This should cost about $335.00 plus tax.

The 4L60E transmission will not last in a 4-wheel drive truck that has oversize tires, unless both rear end ratios are changed to allow for the larger tire size.

Change your fluid and filter about every 20,000 miles. This is a preventive measure, not a fix for a problem.

As a general rule the better the warranty the higher the price. Most shops have a local warranty, meaning they do their own warranty work. A nation wide warranty will cost you a lot more. Don’t get a national warranty unless you’ll be out of town most of the time.

An electronic 4L60E transmission must have clean battery cables to work correctly, because this could cause low battery voltage. If your transmission goes into limp mode it will only have 2nd&3rd gear. If this happens for a reason other than a transmission problem, disconnect the battery to take it out of limp mode.

Never use a transmission additive that says it will stop leaks, because it will turn your seals to mush over time. If your 4L60E transmission has high mileage, don’t try to do a patch job, if you develop a problem have it rebuilt. Over 100,000 miles is high mileage.

If you don’t have a lot of experience installing transmissions, don’t buy the rebuilt transmission and install it yourself. If a shop rebuilds & installs your transmission, they will only charge you for one installation fee, regardless of how many times they have to take it back out. If you do the job, it’s your problem if the transmission is defective.

Some problems that can be mistaken as a transmission problem are motor mounts, fuel filter, spark plug wires, catalytic converter, fan clutch, U-joints and others. Never rebuild your transmission without an expert diagnosis first. When it’s done, you may still have the same problem.

Post by **HenryJ** » Thu Nov 10, 2005 5:05 pm

Update: Add the servos and longer pin to your wish list. They really do make the transmission shift as it should. Quick and firm.
Don't expect them to "spill your coffee" , but it is nice to have positive shifts. The over drive shift is holding longer too. It is not nearly as much of a bog as it once was.

I don't know how it will feel for those with smaller tires, or a lower final gear ratio, but it does work well for my combination.

I would say that if you feel your transmission shifts sloppy, mushy or late under moderate throttle. This is the answer.

quickbiker · Post by **quickbiker** » Mon Apr 16, 2007 6:47 pm

OK, so this is the pin.

This is for 3-4?

And what is for 2-3????

Or I just need the 2 of those?

Post by **HenryJ** » Mon Apr 16, 2007 7:00 pm

quickbiker wrote:And what is for 2-3????

CORVETTE SERVO 700R4 4L60 4L60E E CAMARO TRANSGO $12.95

24digger · Post by **24digger** » Sun Apr 22, 2007 6:27 am

OK, I'm really thinking about doing this mod on my 95 I have always hate the way it shifts. I'm assuming this will work on all s10's with this transmation?

What all do I need?

There's a lot of links posted for different things.

Post by **HenryJ** » Sun Apr 22, 2007 9:50 am

The three links above your post should do it.

You need:
Corvette servo
Longer pin
Billet 4th servo

24digger · Post by **24digger** » Sun Apr 22, 2007 11:33 am

Thanks I'll get started on getting them.

24digger · Post by **24digger** » Wed May 02, 2007 2:35 pm

Got all my parts today plan on installing this weekend

Post by **HenryJ** » Wed May 02, 2007 3:39 pm

Please document the install and write it up as best you can.
Another point of view on the install is always invaluable information.

24digger · Post by **24digger** » Sat May 05, 2007 3:51 pm

Well all went well I think, after coming back and looking through your write up, I don't remember seeing the inner spring. It must have stayed in place because I never saw it anywhere and everything went back together ok.

On my 95 I've got edelbrock tubular exhaust and there was noway to get to the servo cover with it on there. I had to take the lower y-pipe collector off to get to it. Once it was off it was smooth sailing except for the heat shield mounted to the bottom of the cab. I had to pry a dent into it to get the inner servo out.

Other than that it was a breeze. HenryJ is right about the seal I couldn't get my cap off until I cut it, pulled it out and it came right out.

It took me about 2 hours to complete servos because of exhaust having to come off. Then since I have never changed trans filter because the way exhaust runs right if front of pan I don't think I could have ever gotten the pan down.

I would say if you have a body lift you should have no problem as HenryJ did.

I'm still worried about that inner spring but I did have to pry on outer cap several time to get the C-ring seat in there good.

Now results definetly shifts a litte firmer I thought it woud shift quicker and harder but I haven't driven it in a while so my memory have forgotten exactly how it shifted.

Will give another update later. I didn't drive it all that far.

F9K9 · Post by **F9K9** » Sat May 05, 2007 5:14 pm

Thanks for the info. I definitely want to perform this mod this summer.

24digger · Post by **24digger** » Sun Sep 02, 2007 2:21 pm

Just wanted to update, love the way it holds 4th gear longer, but not real sure if I like the way 2nd and 3rd shift. A little firm for me but I guess I'll have to live with it, but I am starting to get used to it.

Post by **HenryJ** » Sun Sep 02, 2007 2:54 pm

Hopefully your transmission will live longer. No more mushy shifts and better holding power.

green02crew · Post by **green02crew** » Tue Aug 12, 2008 8:04 pm

What is the difference between these two?
Billet 4th Servo
Billet 4th Superior Super Servo

Apparently there is a package for the Corvette servo and longer pin.

Post by **HenryJ** » Tue Aug 12, 2008 8:09 pm

green02crew wrote:What is the difference between these two?
Billet 4th Servo
Billet 4th Superior Super Servo

Email oregon performance transmission and ask that question. They were very helpful when I had questions. Be sure to fill us in here afterward.

green02crew · Post by **green02crew** » Mon Aug 18, 2008 12:33 pm

Well after two attempts to contact from me and no reply I am left out in the open. Which one did you purchase HJ? The first one is a couple bucks more but seems better overall... I really don't know though as the descriptions are rather vague.

Post by **HenryJ** » Mon Aug 18, 2008 1:10 pm

green02crew wrote:Which one did you purchase HJ?

I ordered the 4L60E BILLET 4TH SUPERIOR SUPER SERVO and the 4L60E LONG SERVO PIN

green02crew · Post by **green02crew** » Mon Aug 18, 2008 1:12 pm

Well I guess I'll close my eyes and point to one... After install would removing torque management be ok to do? I want to take full advantage of the hardware but not kill my tranny. Should I just drop a little of it or none at all or all of it?

Post by **HenryJ** » Mon Aug 18, 2008 2:19 pm

green02crew wrote:Well I guess I'll close my eyes and point to one...

Ahh, don't trust that I selected the right one?

...would removing torque management be ok to do?

As Ok as it would have been before the servos.
Torque management pulls timing to soften the shifts.
Why don't you try one thing and see if it gets where you want to be. If you need more , there are more options.
My tranny is in its "happy place". I am content to stay right where I am.

green02crew · Post by **green02crew** » Mon Aug 18, 2008 3:14 pm

Oh I trust your decision I just hate not knowing the differences being that theres only a few dollars between the two.

Have you reduced torque management at all personally?

Post by **HenryJ** » Mon Aug 18, 2008 3:31 pm

green02crew wrote:Have you reduced torque management at all personally?

No. That requires custom programming the PCM. I do not have the software to do that, yet.
I use the HPPIII to do what I need done and see no need to do a custom tune as well.
Weight the cost versus gains before you invest in another mod.

green02crew · Post by **green02crew** » Mon Sep 01, 2008 7:12 am

I finally got an answer, the difference between the two 4th gears is: "MAINLY JUST NAME BRANDS THEY BOTH DO THE SAME THING."

green02crew · Post by **green02crew** » Sat Sep 13, 2008 6:10 am

Parts are in. Am I able to do these by myself in a parking lot with very few tools and no ramps or lift?

Post by **HenryJ** » Sat Sep 13, 2008 6:19 am

Are you body lifted?

green02crew · Post by **green02crew** » Sat Sep 13, 2008 7:06 pm

Negative on the body lift.

Post by **HenryJ** » Sat Sep 13, 2008 7:08 pm

Gonna be tight. Be prepared for some cuss'n. The higher you can get it the better. Buying ramps might be worth the investment.

green02crew · Post by **green02crew** » Sat Oct 04, 2008 8:51 pm

Well I gave it a shot this weekend with a crowbar. The servo cover doesn't budge. I can get an ok handle on it but can't seem to get it to depress inward to release the clip holding it on. The transmission will move when I push hard enough on the servo cover but thats it. Would a large c clamp work or should I get it to a tranny shop that has a gm tool?

Post by **HenryJ** » Sun Oct 05, 2008 6:20 am

It is tight and I have heard several that have had problems the first time.

It really must be pushed in straight. You may need to make sure everything is still in there right. The spring can easily fall. I read one report where something was installed backward. You might have to get a new o-ring for the cover if you damage it or have to cut it to pull everything apart for a check.

I wish you luck. Sorry I can't be of much more help

green02crew · Post by **green02crew** » Wed Nov 19, 2008 7:17 pm

Well a little update on the servos. They do make a good difference in tranny operation. I am satisfied at this point.

The install was not so good. The longer pin was about 1/16" too long and had to be ground down slightly but is still longer than stock. The cover would go on but it bound up. The exhaust had to be removed and the tranny crossmember had to be taken out as well to get the room. Those of you with body lifts and or no precat are lucky. Overall I am happy with the results and it is well worth the small cost.

Post by **HenryJ** » Wed Nov 19, 2008 7:59 pm

It just feels right is the best description that i can come up with.