Best servo?

[OneLethal87GN]

Before I buy I wanted to know what the best servo would be? I've heard the billet one then I've heard of an "old 200" servo. I read in some back issues of "The Source" that using an old 200 servo would cause breakage in the 3rd gear clutch. I want a good firm chirp-style shift but don't want to break any parts. Has anyone had any damage from either type of servo? I want to do this rebuild right and not have tranny problems for a longgggg time.

 

[OneLethal87GN]

Anyone? I'm going tomorrow to work out the details on my rebuild and want to know what servo to put in. I've also heard of a servo out of a Corvette being used. Any input is greatly appreciated. Thanks.

 

[chris718]

our 200 servo has more apply area and the least complaints of all others out there ,according to my customers not just me.as for overhaul kit 349 will get you all the seals,rings,gaskets ,filter ,bushings ,washers and selective washers,alto wide red band,alto direct clutches and kolene steels,updated 3 pack 4th gear set up,and all the other clutches and steels w/forward wave plate.

 

[Otto J]

Originally posted by OneLethal87GN
Anyone? I'm going tomorrow to work out the details on my rebuild and want to know what servo to put in. I've also heard of a servo out of a Corvette being used. Any input is greatly appreciated. Thanks.

THe one out of hte corvette will not work, A corvette has a 700R4 or a 4760e depending on hte year, Either way they will not work in a 2004r

 

[OneLethal87GN]

Well, it sucks but I'm going with AAMCO to do the tranny. If it weren't for their 3 yr/36,000 mile warranty I would have gone with one of the aftermarket built trannies. I do have a concern though. I told them to get a servo for an 87 tranny even though I have an 85 tranny in it. The guy on the phone said something about blocking something in the tranny off to accomplish the same thing. What is he referring to and wouldn't a servo be better? I wanted to get a servo from CK but they said they wouldn't warranty it if they put it in. I thought I just read about someone saying the blocking method actually lowers pressures and is bad for the tranny even though it does accomplish firmer shifts. Any suggestions?

 

[jakeshoe]

Better read all the fine print with their warranty...
You'll be getting to know them really well..

 

[OneLethal87GN]

I've made it pretty well known to them that I'm not the kind to get run over. I had a discussion as soon as I got off work today about the warranty. I made it known that the car won't be taken to the drag strip but if it does mess up that they will honor the warranty. BTW, the part they were talking about plugging up is a small hole they say the 85 tranny has in its servo.

 

[jakeshoe]

If I were you,
I would print out the Build tips at the top of this forum and take it to them...
It is by no means the only way to do the 200-4r but it is a good starting point.

The servo is the actuating device for the 2nd gear band. If you use a small stock 85 BQ code trans servo you will liekly burn up the band.
This is a PITA for Aamco and WILL creat downtime for you from your car.
Is it a daily driver?

A stock 86-87 GN servo, the 200 3 speed, or a bilelt unit would be a better choice.

Hope they use a good band in it too...

You gets what ya pay for.

 

[87GN_70GS]

The Superior/Fairbanks servo is 11% larger than stock.

The Sonnax servo is 17% larger than stock.

 

[Otto J]

I had nothing but problems with the sonnax servo.
Just buy the GM one from CK and be done,It works just as good of not better than the billet ones,and no harsh3-2 downshift
And its about half or less the price of the others

 

[OneLethal87GN]

I've told them a million times to use a servo. The tranny builder thinks that if he blocks the hole in the 85 servo that it will act as the 86-87 solid servo does. I've also tried to get them to use a stock 86-87 or upgraded servo. They don't want to use it. I am having a kevlar band installed along with a hardened sprag. He says that with the hole blocked and the shift kit I should be fine as far as the band is concerned. I tried to find that pic that shows the difference in the 84-85 and 86-87 servo assemblies but can't find it in any of my old catalogs. Anybody know where I can find this pic? I don't have ink in my printer so it would have to be in a catalog or something I may already have.

 

[jakeshoe]

One Lethal,
Maybe someone can chime in here but I measured a 85 GN servo and an 86 just last week (didn't write it in my notes...but will tomorrow).
Seems there was ~3/16" difference in the diameter of the apply portion of the piston.
That is a large overall difference in apply area and therefore hydraulic pressure on the band.
I would also highly recommend NOT using the Kevlar band.

I also had one of those I could have taken you a pic of last week..It was very low mileage, torn up, and suprisingly the drum was still perfect.
Usually they wear the drum.
They can work OK on a hard thick drum in limited use like a TH350 or 400 where they are only used for engine braking and the drum is heavy enough to take the heat.
In a 200 or 700 the drum is considerably lighter duty and will wear from the kevlar band.
I don't use Kevlar for any application.

The 86 servo is not solid...

Obviously your trans guy does not understand basic hydraulics.

Good luck...

 

[A. G. Olphart]

Kind of looks like you can get a new tranny guy now, or you can get a new tranny guy later...

Just on the off chance you've never had any hydraulics exposure, this is what Jakeshoe was referring to: The application pressure on the band is equal to the product of the hydraulic pressure and the area of the servo.
Pounds of force= (apply PSI) * (servo area in square inches)

If GM hadn't realized that the early servo was small for this application, they wouldn't have spent the beans to upsize it in the later trannys.

If you decide to go with the Alto red/wide band, bigger yet is needed to get the same clamping force per square inch of band material.

 

[87buick3825]

Warrenty ???? Yes I can see the car sitting there for weeks on end ... Sir we are doing the best we can !! BUT it is under warrenty EXCEPT for the abuse that it looks like you have been putting on this transmission

RD

 

[OneLethal87GN]

Believe me, I already know most of what you guys are telling me. The problem is that it is hard to find tranny builders in my area that know about the 200-4R. The guy building it has said time and time again that this tranny was originally built for a Caddy and not for a hot rod. They seem to think that blocking the hole in the servo and using a kevlar band with a hardened sprag will give me a "bulletproof" tranny. They are re-installing the shift kit I got from bruce a while back. I was going to buy a kit with the good stuff and have someone build it with that but getting no warranty and taking the chance that they may or may not know how to properly build a 200-4R made me go with AAMCO and their long warranty. The guy said the only way they wouldn't warranty it is if it comes back with something broken in it that wouldn't come from anything except abuse. I told him it would not see the track but would be tested thoroughly on the street. They tested the car when I brought it in and weren't impressed with the power. I can see their point as before having it towed in I unhooked the wastegate from the turbo so they wouldn't break anything while they had it. I wanted to get a built tranny from one of the vendors but after going through 5-6 trannies in the 5 years I've had the car a warranty superceeded everything else.

 

[Morkai]

AAMCO

Dude, I was going to tell you it sounds like you need to stay away, but they might know what they're doing. Before I ever started on mine, I did a lot of research. One of which was to buy some videos of ebay, they're AAMCO. The guy on the video really seems to know his sh*t (other than the more advanced stuff developed buy shops like PTS and CK) You might wanna ask the guy if he's watched the 200-4r videos?

Other than that, I would try to talk him into the alto red wide band, I have never heard anything good about kevlar bands. Also see if they'll install alto red lined clutches throughout, or at the very least in the direct and OD. It doesn't cost but about $50-70 more for all reds over the standard BW's. I may be wrong, but I think the difference in the GN servos is surface apply area, which would mean it would make a difference plugged cup or no...

As mentioned before, I would print out the 'strengthening the 200-4r' info from Bruce. Tell him you're not trying to tell him what to do or that he doesn't know how to build one, but that you thought he might not be upto date on the latest high performance mods.

 

[OneLethal87GN]

I have went up there and talked with both the sales mgr. and the tranny builder. Both seem to think a kevlar band and the hardened sprag will give me a bulletproof tranny. I tried to get them to use a race kit from one of the vendors but they will only use their parts. I will ask tomorrow if they have an Alto red band or not. I tried time and time again to get them to upgrade my 85 tranny to 87 specs but they seem to think plugging the servo hole will produce the same result. I wanted to get the tranny built with the 200 servo and all race parts but I wanted a warranty more than a race tranny. This is just a daily driver and will not be put on a track as long as I own it. It will be put to the test on the street though. The parts should be in by tomorrow morning and the tranny should be in the car and ready to test by the time I get off work Wednesday. I will hook the turbo back up and give it a good 20+psi workout before paying for it. Thanks for all the responses. Like I said, I wanted a race built unit from one of the vendors here but a 90 day warranty is not enough for me to shell out $1,500-2,000. Even if the AAMCO tranny keeps breaking down it will still be fixed for free for 3 years.

 

[Lee Thompson]

IMO

IMO the worst thing you can do is --install and go directly out and hammer it. Do they say anything about some easy miles for the clutches and band to seat?
I/m in agreement with all these other Buick guy. Most warrentys have an OUT some where.
Sounds as though you are set on going with AAMCO, so best of luck.