Hello, new guy with a couple of 200-4R questions

[theo]

Firstly, hi to all, this is my first post here.

I've been lurking about in the background for a while, seems there's an awful lot of knowledge floating about, hopefully I can borrow some of it?!
I'm looking into doing an o/d tranny project for my 1980 vette, and having weighed up the options between 700-r4 and 200-4r, I'm pretty keen to go the 200-4r route. I think the ratios of the 200 will suit my diff gearing and I don't think I'm a fan of the very low 1st in the 700. I'm expecting to have to do a reasonable amount of internal upgrades, the vette's presently only putting out about 300fwhp, but I'd like the tranny to hold up against any future mods!

Anyway, my main problem is that I'm in the UK, and the shipping of a ready built gearbox from the States is going to be a killer. I'm set up to actually carry out my own rebuild, have access to a machine shop and experience in spanner turning, so the thought has occured to me that it may be a good idea to search out a rebuildable core over here in England. That's where my main question comes in - I imagine there were loads of variants on the basic 200-4r, so which cars would make a good donor for a decent core? I guess I need an application chart of some sort. Worn out old 80's Caddies and Buicks turn up on ebay over here all the time, if I knew which of these might be carrying a decent "buildable" box, I'd even entertain buying a tatty car as a donor and selling it on after.
Getting a core over here and then only shelling out for shipping on the performance internals would probably work out quite a bit cheaper than shipping a new box, and of course I can spread the cost which is a big plus.
Looking forward to hearing your thoughts.

Cheers
Theo

 

[A. G. Olphart]

Hi Theo, and welcome.

Since you have been lurking a while, this information may all be old to you, but does relate to your query. First, a web site showing the performance and non performance models: http://members.aol.com/powerrslid/thm2004r.html

The performance cores are usually hard to find; Chris has a shift modification kit for the Cadillac AA transmissions, which will likely be the easiest suitable core to locate. (There should be a tag on the passenger side of the tailshaft with AA in large letters, along with other stuff).

Since you may do the rebuild yourself, your first acquisition should be Chris K's book. (Even if you don't build it yourself, this book should help a person converse intelligently with the builder). At a glance, I don't see it listed on his web site, but he has plenty of parts for the 200-R: http://www.ckperformance.com/resources/GM2004RCATALOG.html

For the book, either email or give him a call at his business:

CK PERFORMANCE RACING AUTOMATICS USA
9-16 37TH AVENUE L.I.C. NY 11101
718-784-4256-PHONE/718-784-4252-FAX
TRANNYMAN0101@AOL.COM

CK PERFORMANCE RACING AUTOMATICS CANADA
PRODUCT IMPORT, SALES AND DISTRIBUTION
613-229-7169-PHONE
CKPERFORMANCE@MAGMA.CA

I've shown his Canadian associate in case there might be shipping or tax advantages in buying from there.

There is one specialized tool that is (almost?) mandatory: a low reverse center support removal tool. Here is a related link (with links):
http://turbobuick.com/forums/showthread.php?t=178426&highlight=tools

HTH

 

[chris718]

thanks for mentioning the book.theo we sent you an email regarding price to ship manual to england and never got a reply.

 

[theo]

Hey guys,

Thanks for the replies so far. I've just recently done a stock rebuild on the th350 in my vette, so I know at least what kind of thing to expect. I have the Haynes techbook on the GM trannies (amazingly this is pretty good, for a Haynes!) and looking through the 200-4r section of that, I was expecting to need the low/rev support remover tool at the very least.

A.G, that link you posted - I actually found that page just yesterday, around the same time as I posted my original questions here. That was the kind of thing I was looking for, thanks.
One, possibly stupid, question about that page - I assume all the cores typed in bold are the ones that make a good starting point?
What exactly is it that makes a core a performance one? I assume it's all in the valve-body calibrations, but are there more differences? I would have imagined the cases would all be the same, just the v/b different?

Chris - hey, thanks for your emails so far. I don't know when you sent the email about the uk shipping, but I only received it yesterday! So, sorry if I gave the impression I wasn't interested, my work email system has been total crap of late! I'll reply to you seperately under that email.
What does your modification kit for the Caddy AA trannies consist of? A Caddy core may well be the most easy choice for me. There are (relatively!) many tired old 80s Cadillacs cropping up for sale on ebay and in the pages of the american car mags over here, most of them for a few hundred quid.

Cheers
Theo

 

[A. G. Olphart]

A.G, that link you posted - I actually found that page just yesterday... SNIP
... I assume all the cores typed in bold are the ones that make a good starting point?
What exactly is it that makes a core a performance one? I assume it's all in the valve-body calibrations, but are there more differences? I would have imagined the cases would all be the same, just the v/b different? ...


Cheers
Theo

Theo,

The bold typed codes were the factory performance versions; they had different governor weights, larger 2nd gear servo pistons, and performance oriented shift timing in the valve body. (I'd guess that there were a few less noticeable differences as well, like accumulator springs and such). I seem to recall reading somewhere (sorry, no reference) that the 84 and later transmissions are the ones to build.

GM did continue making changes through the years, but AFIK, not to the case itself. With a Vette, you need the universal bell housing case, not one of the early BuickOldsPontiac only variety.

Were I in your place, core condition would be important; grey, burned smelling fluid quite possibly indicates the need for a direct drum, and rough bits having run throughout. Should Lady Luck smile upon you, the Monte Carlo SS version is nice.
From my reading, few low performance valve bodies lend themselves readily to high performance usage, which is why I mentioned the AA.

Again, Luck...

 

[theo]

Cheers A.G,

I'd already heard about the differences in bell housing, and the need for the universal variety to fit to the vette.

Is the shift timing and hydraulic pressure controlled exclusively by the components in the valvebody? If so, then would it be possible to uprate any valvebody by simply installing a shift kit/different springs/different spacer plate etc? I guess if some of the actual bore sizes in the valving are different between performance/non-performance valvebodies then the answer is "no", without major surgery!

Does having a larger 2nd gear servo mean changing the size of the bore in the case? (I think I'm right in assuming that this servo is the one that is under the clipped-in cover in the side of the case, and acts on the band, similar to my th350??) Or will a bigger servo fit any case?
Hopefully, if Chris can outline what his AA valvebody upgrade kit consists of, that might answer some of my questions above.

Thanks again for taking the time to answer my questions, there's probably going to be a lot more of them, before I can actually make an informed purchase!

Cheers
Theo

 

[A. G. Olphart]

Cheers A.G,

SNIP ...if some of the actual bore sizes in the valving are different between performance/non-performance valvebodies then the answer is "no", without major surgery!

Does having a larger 2nd gear servo mean changing the size of the bore in the case? (I think I'm right in assuming that this servo is the one that is under the clipped-in cover in the side of the case, and acts on the band, similar to my th350??) Or will a bigger servo fit any case?
Hopefully, if Chris can outline what his AA valvebody upgrade kit consists of, that might answer some of my questions above.

Thanks again for taking the time to answer my questions, there's probably going to be a lot more of them, before I can actually make an informed purchase!

Cheers
Theo

Theo,

I've read, but not verified, that spool sizes differ between valve bodies.

Case bore need not be modified. The inner diameter of the cover is cut to match the size of the servo piston with which it works.

You are welcome!
(We have about reached the extent of my limited expertise) :wink:

 

[theo]

Aha. Yeah, that was what I was getting at. I wondered if the spools were different diameters, just wasn't using the correct terminology :biggrin: So if this is true I cannot avoid getting a core with a "performance" vb, as I'm not in the mood for boring out spool valves, machine shop access or not!

Makes sense about the servo, so the two are supplied as a matched set? Well that's one thing in my favour.

When my email system is behaving itself again I'll be getting back in touch with Chris re: the rebuild manual. In the meantime I'm keeping an eye on ebay for a decent core. No doubt this is going to be a long process, but I can live with that. In fact the longer it takes, the more I will have learned before tearing into it.

One thing surprised me: in looking through some of those links you posted, it seems to be quite common for people to end up tearing the box out more than once to get it right after making mistakes the first time. Surely they're not THAT bad??! I know the autobox is probably the least understood and most complex mechanical part of the car, but is it really that common to f*ck it up on the first attempt? Is this just a bad feature of the 200 (I thought the 350 rebuild was pretty straightforward, to be honest)? Guess you have to be careful in your reply, to avoid offending anyone's abilities!

I've got about ten years experience in this avenue, worked as a mechanic for about four years on and off, formally trained as a mechanical engineer, (only recently out of university) - hopefully I've got at least a half decent chance of getting this right??!

And your "limited expertise" has extended mine a bit, so it's all good!

Cheers
Theo

 

[77 cruiser]

They are a bit more complicated than a 350, more working parts & fluid circuits to pay attention to. They have a lot of checkballs to put in the proper places. Other than that if you have a manual & are careful you shouldn't have a problem.

As far as the VB it's the spool sizes that are diff. along with some of the springs. I had a couple apart a while ago & speced em out one was a CQ early Monte SS, a KC & CU.

http://webpages.charter.net/77cruiser/CQ.rtf
http://webpages.charter.net/77cruiser/CU.rtf
http://webpages.charter.net/77cruiser/KC.rtf

 

[theo]

Hey Jim,

I might be being just a bit stupid, but I'm having a hard time deciphering exactly what means what in your attached tables! Either there are some headings missing from the tables or I'm just not getting your layout, sorry, can you elaborate a bit more on what measurements are what? Thanks muchly,

Theo

 

[77 cruiser]

The CQ sheet has the nos. & name of the valves like in the diagram here.

http://www.gnttype.org/techarea/transmission/valvebody.html

The measurements are the dia. of the lands the length & dia. of the springs, also the wire dia. of the springs.

Hope that helps.

 

[theo]

Jim,

Thanks a lot, it all makes much more sense now! I had only looked at the two info tables that didn't have the actual parts list.

Good link....


Cheers
Theo