I would like your opinions on whether to rebuild the Slim Jim in my '63 F-85 or install a 200-4R. Currently, it shifts fine from first to second, but slips going into third. As a result, I manually shift from second to third and have been doing this since I bought it over a year ago. Kinda fun manually shifting, but that will probably come to a quick end when I least expect it. See if my thought process makes sense: I can get an experienced trans mechanic to remove/replace the tranny. I schlep it to a rebuilder with whom he has a track record. All in, approx 3 large. Everything else on the car is original and I would like to keep it that way. And here's the 'but.' I spend $3k and still have the crappy Slim Jim. Would it not be better to spend a bit more to install a 200-4R? Better reliability? And, in effect, having an 'OD' gear would be a bonus. I realize that this route requires getting several adapters (starter plate kit, throttle valve cable assembly + connection to carb). It is my understanding that the crossmember will have to be replaced or relocated + new trans mounts and new slip yoke on drive shaft. Sounds daunting to me, but I'm guessing some of you intrepid folks have done this. I am not experienced enough to do any of this work myself. The Cutlass is not a show car and I don't care if installing the 200-4R diminishes its value.

Your thoughts as you go back for seconds on the pumpkin pie?

 

I wasn’t aware of the 63 F-85 had a slim Jim trans. I thought it was only on full size cars.

 

According to the Q&A section of the June 2021 Hemmings Muscle Machines, pg 52, there were two models; the "Roto Hydra-Matic 200 on midsize cares and Roto Hydra-Matic 275 on full-size cars, . . . ." It is my understanding that both eventually bore the moniker of 'Slim Jim.' If I am wrong about that I would surely like to know. Thanks.

 

The trans in the 61-63 cars is not a "slim jim", and Hemmings is not a reliable source of factory information. The trans is a RotoHydramatic 5. It was only used in the 1961-63 F85 and Cutlass models (Buick used a two speed Dynaflow). No modern trans easily interchanges. Not only is the bolt pattern completely different, but the RH5 is tiny as automatics go and the trans tunnel is quite small. About the only trans that fits without major floorpan surgery is a three speed TH200. The 200-4R is significantly larger, as is the TH350. D&D sells the trans adapter kit.

 

Buick used a Dual Path on the Specials and Skylarks. Mechanics didn't even work on them. The just pulled them and replaced them with a factory rebuilt from Buick.

 

A little more info. The RH5 was also called the Model 240 (NOT the "200" as claimed by Hemmings). It did not use a conventional torque converter. The engine actually uses a heavier flywheel (not a flexplate) with a spring loaded center hub like the middle of a manual trans clutch disc. The trans has an input shaft that looks like the one on a manual trans. There is a fluid coupling buried down inside the trans.

 

Thanks, Joe. I trust your information more than Hemmings. I wonder why the previous owner claimed it had a 'Slim Jim' trans? If I recall correctly, a fellow in our car club used the aluminum block 215 (same engine as in my Cutlass) out of a Buick for his Model A project and claimed that the Buick had a 'Slim Jim' trans. I wonder where all the confusion arose? I appreciate your setting the record straight. I guess the one piece if information I did get correct from the previous owner is that the trans did not have a torque converter.

I definitely do not want to do major sheet metal surgery to the Cutlass. Given that, is a rebuild the only feasible option or should I seriously consider the TH200? For future reference, what trans is known as the 'Slim Jim'?

 

The RH10 used in the full size cars behind the 394 is normally called the Slim Jim. People say a lot of incorrect things.

 

It's funny how many B-O-P auto transmissions prior to the TH400 seem to get incorrectly called a Slim Jim by the general public, just like every 4 speed is magically a Muncie Rock Crusher.

 

Before you condemn the transmission , Try a few simple things first . If you haven't already ,
Is the fluid at the proper level ?
Have you tried changing the trans fluid and filter or pickup screen ?
Use only Dexron III / Mercon in this transmission .
If the fluid is anything other than bright red , it needs changing .
The trans oil pan has to come off to completely drain this trans .

 

Charlie,
Yep, already changed fluid (found Type A), pan completely off and cleaned, new gasket. There was only a slight improvement in shifting. Thanks for the suggestion.

 

Yep just like every 2 speed transmission is a powerglide!

 

Who cares about the exact model of an archaic piece of scrap? In seriousness, the education is good

Throw that superototurboslimamatic in the metal pile or give it to someone here that wants it. UPGRADE to a less archaic 200-4R and get more enjoyment out of driving your car as long as the expenditure leaves you feeling warm. Just don’t buy one of the mass market specials, have one built by a specialty builder, a bit of searching here will give you some leads. It may take a little work, attention and creativity to install and dial in but you’ll likely be very happy with the result.

​​​​​​….

 

And again, torch out the tunnel and fabricate a new one in the process...

 

Don't forget you will have to have custom made carpet for the larger hump.

 

Frankly, that will be the least of your problems. Anything other than an RH5 needs an adapter plate. The rear trans mount needs to be fabricated for the longer trans, and keep in mind this is a unibody car, not one with frame rails. The stock driveshaft is small diameter for low ground clearance, which forced GM to use a two piece shaft with a center support and CV joint to keep critical shaft speed down. The tunnel is not centered in the car but is offset to the passenger side to allow the single exhaust pipe (true duals were never a factory option) to fit in the tunnel for ground clearance. A larger trans means rerouted exhaust, likely under the floorpans instead of in the tunnel, which reduces ground clearance significantly. Depending on the size and width of the new tunnel, seat mounting and clearance may be impacted. The collateral damage from a larger trans is significant.

 

Probably is and in itself will probably cost a few hundred bucks. This would be a very expensive swap.

 

Quite right, I've heard the Super Turbine 300 called that, which isn't right.

 

I would rebuild. Kits are available for these transmissions. the transmission doesn't function like a new car but if you wanted that kind of ride why buy an old car. You could restmod the crap out of this car and end up with a newer drive line and braking system and don't forget the suspension system.
Rebuilding and driving a nice car and only being down a few months or trying to make something fit that doesn't belong and every time you change something you will want to change what comes next and on and on and on.
You have a nice car from the picture so rebuilding and enjoying is the quickest and easiest way to that end.
Just my thoughts.
Steve

 

I'm amazed that you even found type A fluid .
Whatever you found , has to be 50 years old .
Type A fluid contained whale oil , and whaling was banned in the seventies .
Hence the development of Dexron as a replacement . .
I'm not sure I would trust any oil that has set on the shelf for 50 years .

 

You can buy Type A brand new. No, I do not know what they use in it today. I've used Dex III in my RH5 for over a decade with no issues.

https://wholesaleca.com/collections/...e-a-quart-12ct

 

That is what I used, Joe.

 

I would suspect that this may be Dexron III labeled as " Type A " and marketed to those who insist on having Type A fluid .

 

Amen to that. Seems like they have Always been that way too.

 

There's a reason why I dropped my subscription to Muscle Machines years ago.

 

Exactly. For decades and decades.

 

Interesting post. Here's a link to the fabrication shop Joe mentioned in an earlier post:

http://aluminumv8.com/

I never imagined I would suggest someone swap to a TH 200. Are those RH5s just as difficult to rebuild and setup as a Slim Jim? As I've mentioned on several threads about the Slim Jim, a standard Meineke technician doesn't have the skills necessary to rebuild a Slim Jim. Is it the same for the RH5? Where would the OP go to have it rebuilt?

 

Conventional wisdom frequently isn't that wise.

Once again, the problem is not using the part as it was originally intended. The 61-63 cars weigh about 2700 lbs, usually came with 3.36 gears, and the stock 215 puts out 155-185 HP in stock form. Well within the capabilities of that trans. GM had problems when they started putting the TH200 in 4,000 lb vehicles behind (admittedly detuned) 305 motors and pushing a 2.41 axle. And keep in mind that the internal commonality between the TH200 and the 200-4R means that a lot of the HD parts developed for the 200-4R also fit the TH200.

 

Update:

Greetings all,
Just wanted to let you all know of a minor miracle with the transmission. I had made the commitment to have the tranny rebuilt by Fatsco in NJ and use the services of a well regarded local mechanic to perform the out and in. I dropped the car off at the mechanic's place on Monday three weeks ago. He agreed to check it out and give me a call the next day. True to his word, the mechanic (Jeff) called me Tuesday late afternoon and said, "You can pick it up any time tomorrow - it's done." I was stunned. I stammered, "Done, wadaya mean?" I fully expected Jeff to tell me that he had the tranny out and was ready to ship up to Fatsco. Jeff said, "I adjusted the throttle linkage a bit, took it out for a test drive, and it shifted better. Took it back in the shop and adjusted the linkage some more and it shifted even better. So I adjusted it a third time and gained improvement again. So I thought after the test drive I should stop there . I think you will be happy with it, so come pick it up any time tomorrow."

I kid you not, it runs and shifts great. Barely noticeable shift from second to third. Since getting the car back, I have taken it out three times for 10 to20 mile drives. Still great. Bottom line: $350 vs about $3,500.

 

Glad you got a successful solution to your problem .
And kudos to your mechanic for trying the simple things first .
It seems that with this trans , and its larger brother the " slim jim " , that precise throttle linkage adjustment is critical to proper operation

 

That's great news. And we need more mechanics like that. Sounds like a very honest guy. Glad it worked out for you.

 

This is a perfect example of how important the linkage adjustment is on a slim jim trans. I will bet very many good transmissions were needlessly rebuilt or replaced because of this. Glad it worked out for you.

 

What I came to learn from Joe P is that, in fact, my '63 Cutlass did not have the 'slim jim' transmission but had the Roto-Hydromatic Model 240 or RH5. However, your point is well taken about many similar transmissions, including the 'slim jim' (RH10) , could have been saved a rebuild with proper throttle linkage adjustment.