GM Transmission Question

[Todd]

My clutch knee has been acting up lately and I thought before I get the T5 in place maybe I should consider a OD auto. I can get a TH350 mock up case, but will the 200R4 or the 700R4 bolt in its place? Its for the Hudson, has a 230 inline 6 and a 9" rear with 3:73 gears. I kinda think the OD would be better than a TH350. Any thoughts? The motor won't be wild, maybe a little cam and a 390cfm carb to wake it up a little.

 

[fluidfloyd]

Todd,

Either of the OD transmissions would be a good choice. The trans mount is further back then the 350 but I don't remamber how much. I have 400T, 350T & a 700R tooling case at work and I will be glad to get those measurements for you. I'll also check for overall case length. Just for your information, a powerglide, 350T, 3 & 4 speen manual will all interchange both in mounting and overall lengths. There were a few special tailshaft lengths for the 350 and maybe the powerglide but they are seldom seen these days. With those 3:73 gears and possibly tall tires you'll be flying!

George

 

[gudgyz]

I'm with George, either of the OD trans would be a good idea. I an 3.7's in my old 350 Holden, about the size of a 70's Nova and was a great fun ratio but a bit tiresome on trips of anything more than a couple of hours. With 26" tall tires it was doing around 3200 rpm at 100Kph, 62.5MPH. An OD trans would drop it to around 2300, much nicer to live with long term.

 

[HELLRAISER79]

A th350 short tail and a th200-4r are the same length from the bellhousing to the end of the shaft. So the driveshaft (27 spline) will work with either. The difference lies in the fact that the crossmember for the th200-4r needs to be back 6 5/8" further than it would be for a th-350. A th700r4 also uses a 27 spline driveshaft but it would need to be 3 inches shorter than one for a th350 or th2004r. The 700r4 crossmember needs to be 2 1/8" further back than it would be for a th350. I would go with the th200-4r as its plenty strong enough(grand nationals use them) and if you wanna go with a th350 later for some reason you can use the same length driveshaft. Th200-4r also have a .67 to 1 overdrive ratio wheras a th700r4 has .70 to 1. The 700r4 has a 3.06 to 1 first gear compared to 2.74 for the th200-4r. FYI im going with a th2004r in my bucket because i have an extra from my wifes monte ss. Sorry if this was too much info.
200-4R700R4/
4L60E4L80E/
4L85ELo2.783.062.4821.571.631.4831.001.001.0040.670.700.75

TH350 (bellhousing pattern - Chevrolet, BOP, Fit-All)

Style A B C D E 6" tailshaft 27 11/16 21 5/8 20 3/8 3 19 1/8 9" tailshaft 30 11/16 21 5/8 20 3/8 3 19 1/8 12" tailshaft 33 27/32 21 5/8 20 3/8 3 19 1/8 ​

2004R (bellhousing pattern - BOP, Fit-All)

Style A B C D E All 27 11/16 integral tailhousing 27 3 19 1/8 ​

700R4 4L60 (4L60E 1993-1995) (bellhousing pattern - Chevrolet)​

​

Style A B C D E All except Corvette 30 23 3/8 22 3 20 Corvette (1982-1996) 29 7/8 23 3/8 22 3 20 ​

Sorry, this became hard to read. Its all at tciauto.com. Everything you need to know about automatic transmissions. Click on technical then transmission dimensions.

 

[LumenAl]

Great information! Thanks for the post... We should ask mike to move this post to the tech section!

 

[Martin]

I was thinking about using a 200 4R once and did some research. I ran across something that showed side by side pictures of the internals of it next to a 700 R4. The 700 R4 parts are considerably stronger, I will see if I can find the pictures and post them. They were used in Grand Nationals, and their survival probably had something to do with the turbo lag providing a relatively soft launch. A stout engine will grenade one of these things in short order. That having been said, in a light car with a small engine, I dont think I would be afraid to use one.

 

[Hotrod46]

Either one should stand up to whatever your 230 can dish out. The 200R4 came in a lot of heavy cars like Cadillacs. The 700, with it's deeper first gear, might be better for you. Your Hudson is probably pretty heavy and it'll help get you rolling with the 230.

Both transmissions are a lot wider than a TH350, so if your Hudson has an X-member, you may need to modify it. The 200R4 is wider on the driver side and the 700 is wider on the passenger side.

Be sure to use the lockup function in the torque converter, since it'll save you another 200 rpm or so and help the trans run cooler. It's not hard to wire.

If you run the 700, try to get an 89 or later, as they had all the updates and are considered to be the most durable.

Also, the most important thing with both transmissions is adjustment of the throttle valve cable on the carb. It HAS to be in the right place AND adjusted right or you can fry your trans before you even know it. I think Holley has a throttle arm adapter that will work with either trans.

One other thought, try asking a local trans shop if they have a junk case laying around. Most shops do and might even give it to you if you tell them what you need it for. Worked for me anyhow.

Mike

 

[Martin]

I found it! I also reread some of the stuff I read when checking into this the first time. Opinions on these things are all over the board, from bulletproof to junk. I am always skeptical of performance claims made by people trying to sell something, so I suspect that a lot of the claims made of these things are beyond what they will really stand up to. It is said that a picture is worth a thousand words, there are a lot of pictures here.

http://www.webrodder.com/article.php?AID=426&SID=6

 

[Hotrod46]

Both transmissions are a lot wider than a TH350, so if your Hudson has an X-member, you may need to modify it. The 200R4 is wider on the driver side

A little more info on this to clarify. The 200R4 isn't that much wider than a TH350, but the pan is longer on the driver side. If you have an X-member, the pan may interfere with it.

The 700 is much wider on the passenger side.

 

[Todd]

Very interesting read Martin. I the Hudson will probably be the wieght of a duece. There is only a tube crossmember for now, no X. 29 or 30 inch tall rear tires. I think I had a 200R4 in my '83 Cadillac wasn't a bad unit. So far I think the 700R4 would be best for the Hudson and the 200R4 would be best for the track t.

 

[fluidfloyd]

Hellraiser79,

Thanks for the information. I did measure the various cases this morning but you just saved me a lot of typing and as I am a ten thumber I do appreciate it.


Todd,

As for choices, I feel the 200R will get the job done just fine. A lot of guys drag race these things in the stock ranks and do OK. Unless you are building a torque monster you should have no problems. Something else to think about, if you are going to run tall tires then you might not even want an overdrive. Run the numbers and see how hard your motor will be turning. One more thing, there are a lot of specialty transmission companies out there. Unless you are going to race it go to a local rebuild shop and save yourself a ton of money. A TCI, B&M or other big name will basically just sell you a rebuild that is no better then your local shop. It is only when you step up to racing transmissions that you see a difference. Hope this will give you something to think about. Good luck.

George

 

[TheAntiBoyd]

Ive had 2 700r4s. A stock one and a modified one with a manual valvebody. to be fair, my 350tpi in the 87 firebird makes a fair amount of torque, and if I pound my foot to the wood and get it to launch, its VERY quick off the line for 3700pds. Im more concerned about the tinfoil rear end in this car than the trans. That being said, get at LEAST an 87 year 700r4. The very early ones had some incredibly weak internals (most first year stuff in any car should be avoided anyway). Then have it upgraded to the corvette valvebody and servos, this will provide more pressure, less slipping and trans runs a lot cooler, without going to a "Shift Improver Kit" (which I have and never use the stiffer shift function anymore). Id also install a pan with a drain plug and a new converter.

I know they have a bad rep, but lets look at why...most of the people who have trouble tend to have mis-adjusted TV cables, or dont use the lock up function...OR grab a boneyard unit, drain it, refill it and throw it under their chevelle behind a 380ft pd modified 350 and expect it to last and get mad when a 100,000 mile auto trans thats probably been neglected and was only designed for about 350-360ftpds in a heavy car, leaves the party.

Put as much thought into a 700r4, as the rest of your build and it'll take anything you can throw at ir. 4L60s can take 10sec drag times with few modifications, so can a 700r4, if you adjust the TV cable properly and refresh it...anyone who pulls a core and runs it....gets what they pay for in my opinion.

As for my modified 700r? Well it lived behind my 383 that at one time had canfield heads, a performer rpm airgap and a 268H with a 20yr old beating it like a stubborn mule. I broke a U Joint, not the trans. If your TV cable is set correctly, and a refreshed 700 with vette internals lets go, its simply because your rear axle and engine are of legendary quality...not because the trans is junk. Its always the weak link that breaks.

Beware the trans rated for horsepower...its torque that kills things. figure 15% above your ballpark torque number and you'll never have a problem. This is all assuming you can get the a$$-end to stick like a prostocker anyway

 

[Ted Brown]

Thanks from an OLD guy, that quit before those OD auto's were good.... Lots of great info here.. I love turbo 400s myself, easy to fix, and not that much money involved either..

 

[kcfatdawg]

Why can't a 350C trans work. It's a lock-up. Works kinda like an OD trans. That way no cutting and chopping anything up..A thought.. Also,if you plan on using a 700R44L604L60E that hasn't been rebuilt yet, there is one part that really should be upgraded. It sometimes is the main failure of these trannies. Change the Reaction Sun Shell for the super heavy duty. The OEM cracks and comes apart where the gear is attached on the backside of the shell where it goes into the low-reverse. I always replace it on rebuilds. Most trans parts guys know it by the name of Monster. cheap fix.

 

[Martin]

Thanks from an OLD guy, that quit before those OD auto's were good.... Lots of great info here.. I love turbo 400s myself, easy to fix, and not that much money involved either..

If you like the TH400, and whats not to like, but want an overdrive, get a 4L80, or 4L80E if you want the electronic version. They are a 400 with an overdrive added.

Antiboyd;
Your point on HP ratings is good. I think most people on here probably know this but for the ones that may not... Horse power is calculated. A dynomometer measures torque and calculates HP using the torque produced and the speed at which it occurs. HP all by its self is meaningless without knowing what speed it is measured at. 250 HP at 1000 RPM will require a pretty stout trans, while 250 HP at 6000 RPM would not. Whenever someone throws a HP number at you, always ask, "at what speed".

 

[HELLRAISER79]

For what its worth my wifes 86 Monte SS has a th200-4r. It also has a zz383 425hp 450tq. It goes 12.37 @ 112 mph with drag radials. It also goes to alot of car shows but does more drag racing. The lockup and fourth gear is great on the highway. We have had no trouble whatsoever
with that trans. I have blew up alot of th700r4's though. I guess it depends on how you rebuild them.

 

[TheAntiBoyd]

One of the dyno companies has a model that actually DOES -MEASURE- horsepower. The name escapes me (its 1am) But whoever the premier name in dynamometers makes one with some super duper computer stuff that actually measures HP in real time, it doesn't calculate it based off of torque...dont ask me how or why LOL. Dynosim (computer dyno simulation program, runs on PC/MAC) is cheap and reasonably accurate, especially considering a Tbuckets limitations in real "street trim." If you get yourself a copy, and "build" your motor...bring it to your local trans guy (Ive broken a TCI circle track trans....I wont buy from them again) Get him to look at the numbers; he SHOULD be able to throw down a trans that will take almost anything you're willing to throw at it.

Side note: Torque converters are a "round about" educated guess. For a SERIOUS performance effort (such as my friend Ed's 630 dyno'd HP 427ci smallblock "shivalay"), you REALLY need to get in touch with a performance TQ converter company and have one built to spec. You may find that you have to install it twice, sending it back after you drive it a little because its too much or not enough for you...they'll dial it in and ship it back. Not really necessary for MOST street cars. I never order a converter out of a book, its better to call B&M, TCI or Hughes for a recommendation; and, tell them your entire situation...weight, specific engine combo, gears, tires and HONEST driving expectations. Being truthful here will make for a more enjoyable car overall.

~Nate