TunedPortZ

i was wondering what advantage is there to installing a corvette servo on a 700 r4, also where do i get one and how much do they cost? are they worth the money? thanks

4L60bliss

Is it worth it? Definatly. Most builders consider it one of the "standard" parts to be replaced. The piston surface is much larger and it gives more holding power of the band for 2nd gear.

Where do you get one? How about, where isn't there one. They are everywhere. You can go to the dealer, you can contact fine establishments like ProBuilt, or you can even do a search on ebay. Here is an auction for a Vette servo and a 500 boost valve! http://cgi.ebay.com/ebaymotors/ws/eB...ADME:B:LC:MT:1

Danno

I would suggest you talk to an expert before you pursue this. You have an early 700 assuming it is stock. 87 and up I believe have the newer version. The older ones suffered from many problems. Installing the vette servo is not a good idea for those boxes. The corvette servo needs a different separator plate and uses a modified valve body. By changing you will generate a VERY harsh shift and run the risk of damaging the sungear shell and input sprag. If you are looking into modifing a 700 R-4 most experts will recommend getting a later version box and then building it up the way you want.

4L60bliss

Sure, getting an '87 or later transmission is usually ideal, but I see no reason why a corvette servo cannot be installed, without problems, into an '86... All the '86s I have done shift rather well.

Danno

I am only passing on information I have gathered over the last few years. A lot has to depend on the relative age of the trans. I have never personally rebuilt a 700R-4 but I have spent much time watching them being done. My last rebuild was a turbo 400. There is a proper way to do modifications to these transmissions and it DOES require more than simply adding the vette servo. While you may have had luck in this area, if he is going to attempt to do it the right way there is more involved. As long as it is apart why not try to be thorough. I have seen several 700's with incomplete mods performed and you usually get a handful of parts falling out. My advice, don't listen to me. Get the advice of a good local trans guy, preferably one who does racing work.

4L60bliss

:sillylol:

Low C1500

Vette servo made my 1-2 hard, and it cleaned up a slightly slippy 2-3 shift, I love it, EBay sells em' cheap.

Danno

How many rebuilds have you done I wonder. Unless you are a qualified transmission technician I'll bet the answer is zero. If you are an expert, then you know the care and precision involved. My limited experience with doing several 400's gave me respect for the guy's who really know what they are doing. Fact is that the 4L60 is not a very strong box, it suffered from strength problems thay are only made worse by generating an extremely harsh shift. But you knew that didn't you? The boards are about exchanging information and idea's and you only demonstrate your ignorance by trying to make a fool of me. When I respond to a post I try to give both up and down sides of a topic. Glad to see I made your day.

TunedPortZ

i was thinking of rebuilding it my self, i have a B&M shift kit, for it but i am not too eager to put it in, we put one in my friends iroc and since he has gone through two trans. and one rear end.....
i have heard the transgo is a much better kit. so if the trans is rebuilt, adding a vette servo would still not be a good idea?

Low C1500

B&M is not the greatest kit, but I put one in at 50k now I have 110k and trans still woks (barely). But thats not bad considering I'm a heavy truck with some power. But definetly pay extra and go transgo!

Danno

Last post is correct. The transgo kit will make a rebuilt 4L60 a very nice transmission. The thing about a later version is that it incorporates the extra valve body as well as some beefier input components. With a rebuild and the proper mods the vette servo is a GREAT improvment. We have a local guru here and he is quite respected, he will absolutely NOT do just the servo piston. While it may make a nice firm shift they always seem to come back within 6mo to a year with major problems. Unless you have done an automatic, I would really think twice about doing it myself. Clearances and tolerances are critical and very exact. Good luck if you tackle it, but take a lot of time and double check everything. I have seen many guys get one done only to get no further than the corner before it fries.

4L60bliss

I'm sure my years of actual hands on experience is no match for the mind boggling wealth of knowledge you possess from all the "watching" you have done.

How many rebuilds have I done? I have no idea. I have been fixing 700/4L60, 4L60-E, 4T60-E and 4T65-Es for several years at a GM Dealership. I am an ASE Certified Master Technician and I'm steps away from being GM Master Technician Certified. This isn't stuff you can send 3 box tops and $9.95 in the mail to get, you must have hands on experience and actually show competence in this field.


You also need to understand the difference between a "firm" shift and a "harsh" shift. Vette servos generally give a "firm" shift, broken, missing or shimmed accumulator springs, oversized 2nd gear feed orifices, and missing check *****, to name a few, give "harsh" shifts.

I agree 100%, harsh shifts will can cause internal damage as it "shocks" the internals. I have a 4T60-E broken down on my bench as we speak w/ an almost completely busted reaction shell thanks to a very harsh shift.

Is that a fact? So I guess that when a stock 305 TBI breaks a transmission, it was all the "power" going into the "weak" 4L60, meanwhile, WS6 Trans Ams, SS Camaros, and C5 Corvettes w/ 4L60-Es, which have near identical internals, and twice the power, doesn't seem to have a problem. Figure that one out...

I'm not saying these transmissions don't have problems, THEY DO, but overall, they are not as bad as everybody makes them out to be.

Low C1500

Come one guys, I'm sure you both have great knowledge on tranny's, but who cares who has rebuilt more tranny's, cause everybody knows there always somebody who has built more of them. And being good at rebuilding a 700r4 is something to be proud of as it is one the most common and extremly complicated things out there, but lets face it boys it not brain surgery. And its true with regular maintaince the 700r4 isn't that bad, in fact it handles my 400 ponies pretty good.

Riley's35089rs+

Here is one for ya....I installed the vette servo, but when I was done I didnt get that "springy" action of the cover..I had to put alot of pressure to get the snap ring back on the cover....I did as instructed...any I deas?

"Once out, you will see that there is a "plate" inside the piston and is spring loaded. You will need to squeeze this together and remove the snap-ring. Once apart, the servo will separate from the pin/spring assembly. Simply install the new servo onto the pin, squeeze the assembly back together and install the snap-ring. Install the new seals and use ATF to lubricate the assembly. When you go to put the assembly back in the trans, look out for the spring still in the case. It may still be on the "nub" or it may have fallen. If you feel inside the case, you will see the hole for the pin is in a raised "nub" and the spring must rest around this nub. Then pry on he tranny again and install the assembly. Once in, push on the assembly, it should feelspringy . If it does, its in right.

Riley's35089rs+

this is interesting....http://www.technicalevolution.com/niceshft.htm I should have used vasoline to lube the assembly huh?

4L60bliss

It was never a battle to see who has done more or knows more, I was just merely defending myself against the statements directed toward me. All I intended to do was answer the original guys question about the Corvette Servo. Not everybody can afford to go out and just trash there "first design" for an '87 and later. Nor can they go out and purchase the TransGo kit and pay to have it installed, or even want to try and do it themselves. I try not to assume what other people are capable of or can afford, I just try and answer the questions as honestly and accuratly as I can, and I think I did so rather well.

A Vette Servo by itself will not kill the transmission. When my transmission in my '87 Trans Am had 140,000 miles on it, it was bone stock, never been apart or had a shift kit installed. I installed a Vette Servo and .471" boost Valve. It shifted great. Quick and Firm. No banging about it. Two years later, the car has over 170,000 miles and the I believe the band has finally started to burn as the 1-2 and 3-4 shifts have softened up. Did the servo do this? HELL NO, I think w/o the servo, it would have done that a long time ago. I'm running mid 13's on a 700R-4 that has 170,000 miles on it. I have seen modded ones that had alot of "good stuff" not last that long.

I do see where you are coming from, a servo alone does not make a tranny, I believe 100% in the TransGo kits, and I highly reccomend them, but read paragraph #1. The Vette Servo is a great improvement over stock and every little bit counts.



As for Reily, sometimes it takes a little extra pressure to compress the assembly into the case. Now that it is installed and the snap-ring is in place, try to push again and see if its "springy". If not, one of the scarf cut teflon seals may have popped out during assembly. Vasoline is good for holding those seals in place during assembly. Good luck.

Danno

Nothing nasty here, just a good heated debate. Fact is this falls into the same category as just about anything else. My good friend also works at a GM dealership and when I stop in to see him it's the same debate whether the topic is synthetic oil or aftermarket chips yada, yada, yada. Half the guys there won't run Dexcool because they claim it generates problems. I was working on Chevy's when the Powerglide was the trans of the day. I never stated the 4L60 was a BAD transmission, only that the later ones are the preferred choice when considering modifications. I too attended school for auto technology back when my 74 camaro had points. My career path change to electronics and I spent many years teaching technicians in the telecommunications industry. I don't claim to know it all, just the opposite because of my questioning nature. Actually Bliss, I am glad I did. You guy's don't get paid anywhere near what you are worth considering todays vehicles. Next time don't throw up a quote and a smilie, simply explain your reasoning and perhaps we will BOTH have a good exchange of ideas since this is the purpose of the boards. How many "E" versions you doing these days. My wife's threw a DTC on the way back from vacation. Couple of thou out of warranty, but they threw in a new valve body after she bitched to Chevy.

4L60bliss

I do quite a few. Between Reaction Shells and Valvebodies, I stay fairly busy. Not as many as I would like.... More than likely, your wifes vehicle set a P1870 (Trans Component Slipping). The 1996 and later 4L60-E has a Torque converter that is gradually applied using a Pulse Width Modulated apply method. To do this, GM used a PWM Solenoid, and a regulated apply valve. The valve is anodized and fitted into an aluminum valvebody. It is excersised so much that it can wear out the bore in the valvebody w/ as little as 20,000 miles. Once the bore becomes oversized, or as GM once stated "egg shaped", the valve can become side loaded and stick. Once the valve sticks, the Torque Convert will not apply, or it will partially apply and slip. The PCM monitors this Slip, and anything over 150 RPMs of slip for a period of time will cause the P1870 to illuminate. The fix for this depends on who you are. Sonnax has a acceptable fix for this, but if you work at a GM Dealer like myself, Valvebody is the only answer.

Most people **** and moan about taking there car to the dealer, but they don't realize that if they get all there services done there, then usually they can get thier car fixed there, at no charge, or at least a 50/50 split, once out of warranty. Its called "goodwill" and the dealer is allowed to be flexible w/ warranty repairs to help out "good customers". I did a Jimmy one time w/ 50,000 miles on it because of a reaction shell, and the dealer covered it because it was a good customer. Some dealers won't acknowledge that a goodwill policy exists, because they try to keep warranty expense down, and others, (like mine unfortunatly) use it generoulsy


As for the DexCool debate, DexCool is GOOD, untill you run the sytem w/ it low. As long as you keep the system full, you won't have trouble. Once it is allowed to run low and air is introduced into the sytem, the heat, and aeration caused by the water pump, turn it into mud. Dexcool mud is a major source of tranny failure as it clogs up the tranny cooler mounted inside the radiator. If you ever get a burnt up tranny for no obvious reason in a vehicle w/ DexCool, take the cap off and look at the cooler.

Danno

I drove it the rest of the way home. I noticed that the shifts got very hard, figured it defaulted to full line pressure. Yeah, it was an 1870. I cleared it and it seemed to be OK for a couple of days, then it triggered again. My dad worked for Chrysler for 30+ years. His first new car was a 53 Chevy that made to and from Calif. where he was stationed in the Navy. *** only knows why he bought a Dodge, but he's on his third box. Hey, thanks for the info and sorry if we got off on the wrong foot. We have 4 Gm cars, my wife's on her third blazer so they have been decent. Plus we had the rusty dipstick problem, don't think that hurt either. It's funny when people talk about dealer being ripoffs, etc. I am in a similiar situation where our company represent's several manufacturers on an authorized level. We see equipment come in that's suffering from very poor and sometimes zero maintenance. They bitch and moan about the equipment and never blame themselves. If you have read some of other posts you'll see that I am a firm believer in OE replacement parts. A lot of the bad rap that some cars get is because everybody wants to pay $79 for an alternator and have it last forever. When the Pep special craps out after 6 mo it's always the car's fault. See Ya, nice night for the sportbike. First day it's been under 90 at 8 at night in I don't know how long.

4L60bliss

Yes, you are correct, that is the PCM's attempt to correct the slip condtion, or at least try and prevent further damage by defaulting to Max Line Pressure. I have seen people go months w/ the check engine light on, and by the time I got to it, the max line pressure had forced the check ***** THROUGH the spacer plate.