# transmissions for my GTO



## Chris-Austria (Dec 23, 2010)

Hi!

I would like to know more about the different transmission Options for my GTO.
I learned a little bit about the Muncie M20, 21 and 22 and know the differences in gears and strenght. But how do they compare to a lets say Th350, Th400 and a 700r4? What are the advantages and disadvantes and how do I calculate for the "best" final gear Ratio (transmission gearing and rear end gearing). I read something about 1st gear gearing and rear end multiplied should be about 10 for a street performance car, is this true?

And what if I want a 5 speed manual like the Tremec500? How do I know what gearing is best and how much overdrive?

I know it's a pretty general question... but I couldn't find really good sources online to learn more about all these transmissions.

What would you prefer for drag racing, manual or automatic? And what is a Th400 full manual? I read that this is very good for drag racing, but on the other hand I always thought that a manual shifter will be faster than an automatic... Now I'm confused :confused


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## Chris-Austria (Dec 23, 2010)

And what do you think about Gear Vendors?


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## ALKYGTO (Mar 29, 2010)

For drag racing, yes an automatic. A "full manual" auto has a "manual valvebody" that requires you to manually shift gears. So even in normal everyday driving you must start in first and the trans will not shift until you move the shifter to the next gear. I've run them and in a hot rod they are not so bad, just remembering you have to shift. Probably not nececcary at the performance level you are at you should be able to do a T-400 with full auto shift or maybe on of the newer overdrives with a stand alone electronic control.

As far as a manual I run a Tremec TKO 600 and it is a fine trans and has held up to the abuses I've subjected it too namely too much HP and a heavy car. It did require some floorpan mods but nothing too drastic and does not alter the interior appearance at all. It has pretty much the same ratios in the first four gears as an M20 Muncie and they have an option of overdrive gears so you can run really any rear ratio from 4:56 to 3:55 I would think no problem. The higher gear ratios might be okay with the overdrive but may bog under acceleration in OD.

I could have put any trans in my car but it was originally a stick, I don't plan on competitively drag racing it and on the street IMO a manual is more fun. Plus they tolerate big cams and radical motors without a whimper and with my Mcleod clutch driveability is top notch close to stock pedal pressure my wife could drive this car. If she dared......:lol:

As far as Gear Vendors all I can say is I've never heard anything bad and it seems like a whole lot of guys on the Hot Rod Drag Week were running them with no problems reported.


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## Chris-Austria (Dec 23, 2010)

I like my M20, but even with my 3:55 gears I sometimes wished I had an overdrive. The gear vendors is really expensive, probably it will be almost the same cost if I buy a Tremec TKO 500 or the gear vendors for my Muncie M20. But if I buy the TKO I have both transmissions.. so I can put it back or sell the M20.

Do you think the Tko500 or 600 would be a better fit for my car?

TKO500 = 3.27 1.98 1.34 1.00 .68 
TKO600 = 2.87 1.89 1.28 1.00 .82 (or .64)

They say that the Tko600 with .64 uses a mechanical clutch type and the other 2 a hydraulic. What do you prefer? I think with my 3.55 gears the TKO500 could be really nice with a pretty long 5th gear for highway cruising.

I don't want to build a drag car, but I read that the GM overdrive transmission like the 700r4, 200r4 and 4l60e are not very good at handling high power levels in old heavy cars. Also I don't really want to convert to an automatic, but if it's "cheap and easy" I would think about it, but only if I get an overdrive that will handle some abuse.

How complicated is a change from M20 to TKO500 with the proper clutch type and everything needed? And will the 3.27 first gear work well with my 3.55 rear or is that too short? (it's 11.6 final gear ratio in 1st and only 7 in 2nd). Is the TKO600 more desireable because the gears are "closer"?

The full manual automtic isn't what I want, thanks for the info. So now it's about a GM overdrive automatic or the TKO500/600. The gear vendors is too expensive for what I would get and I read some articles that people liked the Tremec more than the Muncie with GV... so first step is done.. see what I want and now decide what is best


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## geeteeohguy (Feb 2, 2008)

Chris, 3.55 gears are too steep for the street without an overdrive, especially where you are. If you swapped out your rear end or carrier for a 3.08-3.23, you'd be a lot happier with your car's performance with the 428 you're running. It's MUCH cheaper and less invasive to the car than cutting up your floor pans for a 5 speed. I have personal experience with Gear Vendors units, and they are strong and work, but are clunky on engage/disengage, like what you'd expect on a truck. My advice is to read all you can on the internet and in books and do all the homework you need to do to learn all there is about gear ratios, manual transmissions, automatic transmissions, etc. It's fun, and productive. Then, you can make a rational choice on what you want to do with your car and how you plan on using it.


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## Chris-Austria (Dec 23, 2010)

I don't like the idea of cutting the tunnel, but there is a patch included in the set. Is this very complicated?
My 3.55 gears are fun to drive, but sometimes I miss the overdrive. But I don't want to sacrifice acceleration for the ability to cruise along with low rpm's at highway speeds. Most of the time the car won't see more than 50-60mph, at least not for a longer distance where it would matter. So I would prefer keeping the rear as it is and maybe one day add an overdrive. 

It's not a final decision but I try to learn about all options at the moment. Still it's hard for me to say which Tremec would fit best to the engine and rear and what kind of clutch is better.
I will need to rebuild the old clutch linkage, with a new Tremec with hydraulic clutch, will all the old linkage be removed and something new added? And can I keep my new Centerforce clutch?

The engine starts to make power in the 1800rpm range and runs strong to 5500. 

I don't want to say an rear end change isn't an Option, but I want to think of all that is possible and getting the best performance with still a good balance for highway driving. That is why I want to learn more about the Tremec's.


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## Chris-Austria (Dec 23, 2010)

How hard is it to change from my M20 to a 200-4-r? (for example a TCI Street Fighter)
Will it fit or is there a lot of work and money involved? 
Is it a good match to my 3.55 rear gears?

I know a lot of all options that are possible and after all I think it's between a Richmond 5speed (because I can chose gearing) or the 200-4-r. Maybe a quick change rear is an option, but only if both transmission swaps I mentioned are too much work and money.
The TKO gear ratio isn't that nice I think, the 1st to 2nd drop is really big and I will get a very high primary reduction that won't be helpfull with my rear gear.. I don't want to get above 9:1 because of traction problems.

What do you think?


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## BearGFR (Aug 25, 2008)

Hi Chris,

You'll probably get lots of opinions on this question and I won't profess to try to tell you "which one is right" (if any) ... Mine is that it's going to take a very expensive "custom" version of a 200-4-r to be strong enough to survive behind a strong Pontiac. I shredded a "built" TH400 in my car as a result of an improper burnout procedure, and that transmission at that time was stronger than any normal 200-4-r.

This summer on the Power Tour, I had a long conversation with a rep from Bowler Transmission and his recommendation to me as far as an overdrive was a "built" 4L80E with an add-on external module to provide the electronic control functions those transmissions require. If I ever convert the car away from the TH400 I have in it now (much stronger than the one I shredded), that's what I'll do.

What I like about the various TKO/Richmond options for your car are that it will remain a manual (and manuals are just plain more fun to drive in my opinion), it would allow you to keep the "go" and also be able to cruise comfortably on the highway, and it would be a "minimally invasive" change. Be wary of recommendations for transmissions whose published torque handling ratings are "too low". If you decide to go with a custom build of some sort, pay close attention to the warranty. You're the one spending the money and if something bad happens, you're the one who will feel the pain. It's very true that you could probably get by with just about any transmission as long as you'd be willing to be very careful about how you drive the car and apply load on it --- but where's the fun in that? 

Bear


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## Bensjammin66 (May 12, 2009)

This is all simply my opinion.. 2 cents and nothing more.. 

#1 Making a stick car an auto is just a bad idea. Driving stick shift is wicked good fun and more desirable if you ever plan on selling the car. At least in my experience. 

#2 Bear is right, a 200R is just not strong enough to handle poncho torque unless you through big dollars at it but then at that point, shoulda just bought something else like the 4L80E he mentioned if you insist auto. Which still may require floor mods. 

#3 I "hacked" my floor for my TKO600 5 speed manual but I have a Le Mans and not a GTO. Some purists think to cut the floors up in an original GTO is a sin for overdrive and to some degree they are right. In my opinion, id do it again in a heart beat and will to every hot rod i ever buy. And its far from "hacked." In fact I run a console over top of the tunnel i made and no one would know unless they seen the "5" on the ball or i said something. I did need new carpet orderded a few inches wider to make up for the taller tunnel. Thats just one of the MANY expenses involved in a 5 speed swap. 

You are on the right track though. In my opinion the biggest limiting factor in the muscle car world is the 3 speed auto and 4 speed manual transmissions. Gas is $3.99 not $0.79. Not to mention your motors internals will thank you on road trips. The 1:1 final gear ratios of older trannys hold back alot of rear gear options and can restrict long freeway travel.


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## Chris-Austria (Dec 23, 2010)

I agree that a shifter is more fun than a automatic, especially for such a car! The problem is I can't do such a swap by myself and I don't want to cut the tunnel, that's what was leading me to a 200-4-r. I'm not absolutely sure but I think it would fit without modifications.
I also read that the 4L80E is much stronger (and twice as heavy). But instead of such a transmission I would chose the TKO or Richmond 5 Speed because they all would require a lot of work and be very expensive.

Do you know these transmission? Performance Transmission, Racing Shifter and Torque Converter Car Parts Catalog
Number 1 or 2 should be strong enough on the paper... 

A friend of mine said the TH400 is maybe the best transmission GM ever made.. this makes me even more "afraid" of The Beast now  

Do you know if a Richmond fits easier than a TKO?


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## ALKYGTO (Mar 29, 2010)

TKO all the way. / thread.


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## Bensjammin66 (May 12, 2009)

If I had to guess Richmonds 4+1 require some tunnel mod too but id be guessing. Maybe someone here has one but I cannot say. If you google search Classic Chevy 5 speed they offer complete kits for the tremecs. New weld in tunnel and a template to show what needs cut out. I totally get that its a big under taking espcially if you do not have a pneumatic cutoff wheel or a small saws all of some kind to cut it open then of course body hammers and a mig to stitch it back shut. 

TH400 is a beast, no doubt, heavy input AND output shafts if im not mistaken. But again you will have 1:1 third. Also if you have a muncie now, youll need a longer driveshaft as the muncies and 350s share one but the 400 does not. IMO there is almost no reason to go to a TH400 from your muncie. Its strong enough unless you start moving into bigger 455+ inch motors with good heads. I ran a $400 rebuilt TH350 against a 375hp 455 for quite some time without issue. And i beat my toys pretty dang hard. 

Being a stick car i vote Tremec TKO or stay put with your 4 speed. You already have a flywheel, bellhousing and fork, linkage, cross member and driveshaft all that'll work with it. 
Shorten the driveshaft - $125 
Trans yoke - $50
Awesome Clutch - $269 
Tunnel template and patch - $100 
ARP clutch and flywheel bolts - $60 
Tremec, breathe deep - $2300 
$2900 <--- thats the only ugly about it right there and its a pretty big ugly but remember youll recover some money from selling your 4 speed if you choose to. 

TH400
Good strong rebuilt core $900
Convertor $300
Deep pan and shift kit $125
His/her or some other cool shifter $150-250
Driveshaft $????
$1,600'ish

4 Speed
Free.. 
Or send it out and have it gone through and made tough as nails for about $800-$1000 and accept that 3.23 rear gears are gonna be about it.


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## Chris-Austria (Dec 23, 2010)

What do you think about the TKO's gearing? The drop from 1st to 2nd is really big, almost as the drop from 1st to 3rd with the Muncie. I'm not sure that this is a good thing.. my feeling tells me it will have more traction problems because of the 2.87 and the .82 5th gear isn't the best cruising overdrive I guess.

The Richmond should fit without modification I was told (direct replacement to the Muncie) and the gearing looks good. Here are some examples:

Richmond Road Race: 3.04 / 2.45 / 1.99 / 1.24 / 1.00 
Richmond Street: 3.28 / 2.13 / 1.57 / 1.24 / 1.00 
Richmond Street OD: 2.89 / 1.85 / 1.31 / 1.00 / 0.77 
Richmond 6 Speed: 3.28 / 2.75 / 2.13 / 1.74 / 1.00 / 0.76 

The $3000 plus shipping plus taxes plus costs for th swap isn't a good thing but this might be the first and last transmission change I will do so the most important thing is to get what I really will enjoy.
The Art Carr 200-4-r also looks good and I think I read that it will fit into the tunnel as well. Do you know if the driveshaft length is the same with the 200-4-r and the Muncie? (and the TH350)

I will have to replace the clutch linkage anyway, it's worn out. The Richmond will need the old mechanical linkage, a TKO comes with a new hydraulic one I think. So with the Richmond I could keep at least my old (but pretty new) clutch.

A TH400 or a TH350 are no option instead of my Muncie because I don't see the benefits (1:1 Ratio). If I decide to keep the Muncie for some time I will make it stronger when I replace the clutch linkage... but a overdrive would be really nice


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## Bensjammin66 (May 12, 2009)

Of those, the street od or 6 speed are the only options imo because they are the only true od trannies on that list. The whole point is od right? I run a tko 600 and the drop from 1 to 2 isnt bad at all. Its .64 5th reeeeally drops my final rpm. So much in fact under 50mph I use 4th. 1st gear is a tire roaster for sure. I guess its all preference tremec vs richmond. If they too will support 600 lb ft and require no tunnel mods than the richmond is definitely worth a 2nd look. 
Scrap the 200r idea imo. Converting stick to auto just doesnt feel right.


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## Chris-Austria (Dec 23, 2010)

I now searched all options and did some calculation.
This is what I like the most: http://www.summitracing.com/parts/rmg-7021610ed/overview/make/pontiac

It has a nice ratio and a good OD. The argument for the Richmond is fitment. I will not have to cut the tunnel, just the mounting points and the console will have to be modified a little if the information I got is correct.

Richmond 6 Speed: 2.77 1.88 1.46 1.18 1.00 .62 
Tremec TKO600: 2.87 1.89 1.28 1.00 .64 

I think the lower drop from 1st to 2nd is one point for the Richmond and another point the closer ratio from 2nd to 3rd to 4th. This will probably result in a better ET than the TKO and 4th gear with my tires and rear end equals 101mph at 5500rpm. I guess I won't have to shift into 5th gear on both transmissions for drag race, so my feeling tells me the Richmond is "better". For street driving both should be fine. OD is almost the same, but I'll have to shift one more time with the Richmond.

What do you think?

Oh and yes, I'll stick with a manual now that I know there is one that won't need cutting the tunnel. The Richmond Road Race would even fit better as a direct replacement to the Muncie, but it has no overdrive. I'd have to change the rear gears to get what I want.


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## Orion88 (Apr 24, 2012)

If you're only going to be cruising 50-60mph with 'occasional' higher speeds, I don't think you need to make any modifications. When these cars were build back in the day the typical speed limit was around 55mph, and these cars were very streetable. Sure, a 70 Judge with 3.90's wasn't very happy at those speeds, but with 3.55's I don't see why you need overdrive. It will take a long time to get your money back in saved fuel costs and even with a 428 that doesn't like high-rpm cruising (3000+) you should be perfectly fine. Now here in the states we have 70mph and even 80mph speed limits in some states, so yes, overdrive would be an absolute must with 3.55's for a 'drive anywhere' 428 GTO. If I were you I'd stick with the 4-speed and put the money elsewhere. If it ain't broke, don't fix it! Just my two cents and I'm far from an expert here. Hell, my car was 18 years old by the time I was even born!


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## Chris-Austria (Dec 23, 2010)

Mine was 17 years old when I was born 
At the moment I don't use the highways much because of the gearing, but I will need to drive longer distances now because the Drag races are between 60-250 miles away. For some I can use the "Autobahn" in Germany.. no speed limit at all. I don't want to go faster than about 100mph and most times I drive 80-90mph with the other cars on the highway (or sometimes faster just for fun in Germany).
The nice thing about the 6 Speed is the ability to run 70mph at 2000rpm... this sounds very nice to me even with the 3.55 rear end.

I'm just collecting ideas and information now, the Muncie will be in use for some time. The costs won't amortize for a long long time.. but it's not the only factor. My rebuild engine also uses less fuel than before but I didn't do it to safe fuel.. it's a nice side effect that is saving money. (a full refill of the gas tank is about $170!!)


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