lake_harley

I'm brand new here and am trying to solve a problem (aren't many of us?) I have a 215 Olds V-8 and transmission in a '23 T roadster that I built some years ago. The transmission is what I think is called the RotoHydramatic. It has never shifted well, but I am in the rebuilding process on the car and want to try to improve it.

The main problem is a very sluggish shift from 1st to 2nd. It might actually be a 2nd to 3rd shift as it seems the transmission has a hydraulic to mechanical transition that is also considered a "shift", but it might be very subtle. The transmission also seems very hesitant to ever shift automatically when the shifter is put in "Drive", so I've always just pulled it to "low" and manually advanced the shifter as the car accelerates. I really have to ease up on the throttle to wait for the 1st to 2nd shift. From what I've read, it sounds as though the transmission was not exactly known for it's great shifting, but what I have experienced would have had people picketing Olds dealerships back in the 60's when the F85s were new.

I have done a lot of searching on this transmission, but I guess since it's a one-off transmission that was only used in the 215/F85 I find little and sometime conflicting info. I no longer use the mechanical rod connection from the carburetor to the forward lever on the left side of the transmission. I guess it sends "info" to the transmission on how and when to shift based on throttle position. I have fabricated a cable hook-up to take the place of the rods, etc. I have it arranged so that as throttle is applied it pulls the lever forward against the lever's spring-loaded pressure. I think the cable and lever arrangement takes up most of the available travel on the lever on the transmission, but would like to know if it should be "tight" with wide-open throttle or how it should relate to throttle position?

Also, there's a line, about 3/8" diameter coming off of the tailshaft area. It runs along the body of the transmission to the area of the intake manifold, but because of changes I've made, and the fact it was a "mostly complete" engine and transmission assembly already out of the car when I bought it, I don't know if it's a vent, or perhaps should it be hooked to a vacuum source? My guess is that it's a vent, since it has a small "canister", much like an in-line fuel filter, at the end by the intake manifold and lifter valley cover.

I would appreciate any guidance from anyone who has a similar engine and transmission combo, and say "Thank You!" in advance.

Lynn

joe_padavano

Welcome. Yes, the RH5 is unique to the 1961-63 F-85 line. It is NOT one of GM's better automatics, unfortunately. It is a three speed AT with a fluid coupling in the middle of the trans. The stator vanes in this fluid coupling are alternately locked and unlocked in first gear to effectively provide two gear ratios, similar to the switch pitch converter used on the 64-67 cars. Olds actually refers to this as a "fourth" gear ratio in the service manual. Second gear locks out the fluid coupling entirely, so you have a solid driveline in that gear. You'll note that as you slow down in second, the engine starts to lug if you get too slow, like it does with a manual trans.

I've had some success with improving shift feel on mine by adjusting the throttle valve linkage by trial and error. Ultimately, I plan to ditch it for a T5. You may want to consider a swap yourself. D&D sells an adapter plate to mate to a Chevy pattern trans. Even a TH200 is a better choice, and is about as small as the RH5. Good luck.

lake_harley

Joe,
Thanks for the quick reply! I would gladly have a T5 manual, or other automatic transmission, but it would take a LOT of work to re-build the transmission tunnel in my T roadster. Also the foot area in the roadster is quite cramped already and I don't think I could fit in a clutch pedal too without a major re-construction of a lot of things about the car.

To get me going in the right direction on the throttle/transmission connection to the 215, is there a good starting point? ie: throttle wide open position with my connection cable pulling the spring-loaded transmission lever almost all the way to it's stop? That's something I read in my previous searching, but it was hard for me to quite understand if they were talking about the RotoHydramatic on my 215 or some other similar transmission. Or, perhaps the other direction; throttle at idle with the cable just snug, and about to completely tension and move the lever as soon as the throttle is opened?

I did talk with D&D on several occasions. First time was several years ago when I was initially building my 215 and had come across a very rare 2-4 barrel intake manifold. I had also asked about using the Powerglide 2-speed automatic. The cost to convert to the Powerglide was going to be considerable so I decided to use the Olds transmission at that time. I think I talked with Dan back then.

I talked with them again about 4-6 months ago and again yesterday. The last two occasions I talked with Mark who was really insistent on using about anything OTHER automatic than the Powerglide I already have under my workbench. He was all about other, later 4-speed overdrive automatics. He seemed to ignore my interest in the Powerglide even after pointing out that it probably had a better chance of fitting in the space available in my car without transmission tunnel, floor and firewall modifications. I don't recall him talking about the 200 you mentioned, but maybe that's one of his choices. He didn't seem to be interested or willing to talk about prices on anything, not even prices on adapters and bellhousings they offer on their website. He mentioned the challenge of adapting a conventional torque converter (Powerglide) to the Olds flywheel, but I don't understand why....other automatic transmissions would require a flywheel to torque converter attachment too, so why he seemed a bit argumentative about the Powerglide is beyond me. As I pointed out, floor/transmission tunnel modifications would be a considerable job on this car and I want to avoid that if at all possible. I apologize if I seem upset with my contact with D&D, but I didn't get the feeling he was even trying to be helpful with an engine/transmission adaptation that they might have done before.

I have considered a major change to the car by removing the Olds 215 and replacing it with another engine compatible with the Powerglide. I'm sure the Powerglide would fit and then I wouldn't have to mess with the steel floorboard/transmission tunnel and the fiberglass body interface to make more room.. So, unless I have no other choice than to change everything, I'd like to retain the Olds transmission.

Thanks again!

Lynn

young olds

Did you grab that dual 4 intake? I have an adapter plate and flywheel that lets you bolt chevy automatics up to the 215 I’d consider selling if your interested. I know some guys do the th200 tranny, supposed to be relatively small and easy to fit in the small tunnels the f85’s have

young olds

Btw I daily drove a 62 f85 with the auto and like joe it was trial and error to get it to shift in a way that felt “normal”. Another note that may help, I couldn’t get mine right till I took the edelbrock carb off and put the stock 4gc back on.

joe_padavano

I have no problems with the TV linkage and E-brock carb on mine. I made the linkage and as I noted, took some time to get it adjusted right.

joe_padavano

My 62 Olds has a TV rod, not a cable, but I adjusted it so the throttle valve was actuated sooner in the throttle opening rather than later.


You sure that wasn't a dual two barrel intake? I've never seen a 2x4 bbl for these motors, and frankly, that's a LOT of carb for a 215. Offy made a 2 x 2 bbl intake that you see for sale frequently.

As for talking to D&D, I've never had much success. They only want to build things their way and are extremely unhelpful if you want to do something different.


I personally would avoid the PG. With only 215 cu in and a 1.76 first gear, it will be a dog. Granted your 23 likely isn't very heavy, but still. The TH200 is the smallest 3 speed AT that GM made, and is both common and pretty undesirable due to not being very strong. Fortunately, it is plenty strong for a 215, especially in a light car. Don't confuse the three speed TH200 with the four speed 200-4R, which is what D&D will want to talk you into. That's a considerably larger and longer trans. Of course, the other option is to find a TR8 or Rover trans. The Rover versions are externally identical and use the same bellhousing bolt pattern.

olds 307 and 403

The Powerglide sucks unless you have torque, gearing and light weight. The TH200 trans is very compact but needs improvements to be reliable. The TH2004R has larger dimensions, stronger and has a good OD ratio. The 215 aluminum V8 is a light and unique power plant.

joe_padavano

The TH200 and 200-4R may be the same overall length, but the 200-4R is much larger inside the tunnel.

young olds

Joe, when I got my car it had an edekbrock intake and carb on it already but didn’t seem to have much luck adjusting the tv until I went back to stock intake and carb. As for the dual 4bbl intake, they do exist and I’ve seen one.

olds 307 and 403

Yeah, I forgot the 2004R was that much beefier, modified my post. My local wrecker tried to give me a TH200 a couple of months ago, not even the lock up version. He said it shifted fine as he drove it. Too bad you weren't from around here, looked really clean. It really was a splindly transmission inside and out but has a much better first gear ratio and can be built up. Anytime anything went wrong with one when I worked in a shop, a TH350 went in it's place.

lake_harley

Thanks, one and all for the replies and suggestions.

Regarding the intake, I had the same question when the fellow I bought it from told me what he had. I ended up selling it since I never found a pair of the really small 4 Bbl carbs it was supposed to use. Even the smallest, currently available carbs were too big for the throttle bore openings. From what I was able to find out it apparently was a prototype piece if which perhaps only a couple dozen were ever cast. It had no markings, numbers, or foundry markings of any sort. I agree it would have been WAY over carbed, but it would have had a really COOL factor!

Joe....your summation of talking to D&D was about how I'd put it too. I don't like to be negative about people and how they run their business, but I found Mark rather condescending.

You're absolutely right, the '23 is really light...only about 1350# with gas. I don't necessarily think the PG is the BEST choice, but I'm almost positive it would fit, and the one that was in my Mom's '64 Chevy didn't do too badly behind the 195 HP 283. Of course, I was 16 and anything that didn't have to be pedaled was great by me!

Looking at the photos of the GM Turbo 200 and the 2004R I would have to say the Turbo 200 might be a great candidate in place of a PG. I may have to find one to look at and measure in person to consider as well. Is the bellhousing pattern the same as the PG or other "Chevy" pattern transmissions?

young olds.....I'd like to find out more, and might be interested in the flywheel and adapter plate you have to mount a typical "Chevy" pattern transmission like my PG to a 215. Perhaps send a PM through this group or e-mail me directly at winter62@att.net Could you post or send a photo or two of the parts?

Thanks again everyone! You have all been very helpful!

Lynn

lake_harley

I forgot to ask....can anyone identify if the tube coming from the back of the transmission toward the intake manifold area. Is it a vent, or perhaps a line that should be connected to a vacuum port or something else?

Thanks

Lynn

joe_padavano

Sorry, I meant to answer that. It's a vent. The RH5 doesn't use a vac modulator.

The TH200 will come with either a Chevy bolt pattern, a BOP pattern, or a unisex pattern.

olds 307 and 403

TH200
As you can see this one is BOP. The 2.74 first vs a 1.76 first is a big difference.

2004R

young olds

https://classicoldsmobile.com/forums...***-parts.html Pm me if interested.

Ancient Iron

Personally I would ditch the cables and use the factory linkage. Cables have too much flex you will not get the same accuracy in adjustment.
These transmissions will never be like a more modern G.M. transmission in terms of shifting.

lake_harley

Today I definitely answered one huge question, and that was would a Powerglide or other relatively compact automatic transmission fit in the confines of my existing firewall and transmission tunnel. Unfortunately, the answer was a resounding NO. It hit in so many places it didn't take long to realize that just wasn't an option without major reconstructive surgery. It probably sounds fickle, but that's way down on my list of options now.

So......I guess I'll just stick with the RotoHydramatic and try to adjust it to shift as acceptably as possible. Obviously, a '23 T Roadster is not a daily driver here in Missouri, so I'll just live with it as it is. It is a fun car to drive in any case!

Thanks again, everyone, for offering input and advice! I appreciate your efforts and that you were willing to share your experience and knowledge.

Lynn

joe_padavano

Can't use the stock linkage with an E-brock carb. I had to fabricate new linkage for mine. The stock linkage is a push-style linkage. A cable linkage pulls. There is no "flex" in the cable; the only possible flex would be in the brackets if they are too flimsy. That's really easy to fix if necessary. Frankly, flex is irrelevant. The cable just needs to be adjusted to include any deflection in the brackets.

young olds

That’s probably why I couldn’t get mine to work with the ebrock, previous owner had it set it up with stock linkage

lake_harley

Above is a photo of the driver side of my transmission. All of the discussion about linkage vs cable operation has me feeling I should make sure my thinking isn't just opposite of how things work.

Just to the left of the lever that I have connected to the carburetor linkage I have a small aluminum angle tab. That's where I secure the outer sheath of the cable to the carburetor linkage. When I open the throttle the end of the lever is pulled clockwise, toward the front and somewhat upward by the inner cable. Going from no throttle to wide open takes up almost all of the movement possible on the transmission lever. That movement does have some resistance inside the transmission that tries to return it counterclockwise as the throttle allowed to closed. Is that the correct operation? All of the talk of pull cable vs push-pull linkage has me wanting to make sure the direction isn't opposite of what I described through the use of a bellcrank on the stock linkage. None of that linkage was on the engine or transmission when I bought it years ago, so I was just going on my idea of how I thought things were intended to operate.

Thanks once again!

Lynn

lake_harley

I just looked back at the date of my last post. Quite a lot has happened since then. I had my T Roadster reduced to a pile of parts and one by one I cleaned, primed and painted everything, and finally now have it all back together and took it for state inspection, then licensing next week.

While everything was apart I took the Roto 5 to a local transmission shop and the owner, an older gentleman did a rebuild on the transmission. He was old enough and seemed confident enough that I expect he might have rebuilt other Roto 5s when they were still somewhat common. He had me source a rebuild kit and he did the labor.

He had a manual to follow through the rebuild process but we didn't find a spec on transmission fluid; either the type or the quantity to refill after a rebuild. I'd call it a "dry" transmission and would expect the quantity would be slightly different if it were just drained and had a filter change. So far I have put 4.5 Qts. of Valvoline MAX synthetic dexron (sp?) fluid in it. It seems really "sluggish" and "slips" a lot (high RPM to really get moving) and I wonder if it just takes some time and cycling through the gears, perhaps even driving to get the transmission pistons, pumps and everything purged of air? Anyone have any suggestions from past experience? Also wonder if anyone has a chart or spec of how much fluid I should expect it to ultimately hold? Currently it's at the "full" mark with the engine not running. I'm guessing it should be checked in Park or Neutral after cycling through all gears with the engine running?

I'll say "Thank You" in advance if any of you can once again shed some light on my questions.

Lynn

Charlie Jones

Drain the synthetic fluid out. Replace with Dextron III .
These transmissions were not made to use synthetic fluids .

lake_harley

I do take your recommendation seriously. For my own clarity, is the synthetic too slippery?

One of my other interests is motorcycles. I know on any I've had that have wet clutches that the newest oil formulations are so slippery that it will cause clutches to slip. Is this the same sort of deal? If that's the case, I just hope I haven't damaged the clutch packs with the little I've run the car!

Do you happen to know what the Roto 5 is supposed to hold after a full rebuild?

Lynn

Charlie Jones

The synthetic oil may very well be to slippery . I've also read somewhere that sybthetic oils have softened the "glue" that holds the facings on the plates .
The newest and greatest , is not always the best , when dealing with these old cars,
It may take several changes to get rid of all of the synthetic stuff . I hope you haven't ruined your trans .
According to the 1963 Olds service manual , the F-85 transmission take 4 quarts to refill without removing the pan . 5 quarts if you remove the pan . and 7 quarts to re-fill after an overhaul .
The dipstick should be checked with the engine running .

lake_harley

Thanks for the additional info!! And particular thanks for the refill quantity specs and the proper level checking procedure.

At this point I have only put about 4.5 Qts. in it, and who knows, maybe that's not enough to make it work and that's the immediate problem. But, it will get changed and make sure the synthetic doesn't become a problem if it hasn't already done damage!

I don't think the engine has been run more than 5 minutes since the transmission was rebuilt, and wasn't even in gear for more than about 2 to 3 minutes total when I was moving the car a short distance. Hopefully that wasn't enough to cause any particular damage but I guess time will tell.

I picked up 5 Qts of transmission fluid from O'Rileys Auto Parts (house brand) that's labeled as being appropriate for "Dexron III" applications. I'll drain the pan this afternoon, disconnect and blow out what's in the oil cooler lines and cooler, and start over. I'd hope that 2 changes should dilute the synthetic fluid enough that it wouldn't be a problem.

Now....what to do with all of the "almost new" transmission fluid?

Lynn

lake_harley

So far I drained the transmission pan and cooler and only got out about 2 Qts. of the 4.5 Qts. I had put in. So, there's 2.5 Qts. of synthetic still lurking and now mixed in with conventional Dexron III.

I put the car on jackstands so I could run the engine and run the transmission through the gears without the drag of the wheels not being able to turn easily. After refilling with an initial 2 Qts. of conventional ATF (same as the quantity I drained out) it ended up taking 1 more Qt. to get it up to the "Full" mark on the dipstick. So, at this point the whole system has 5.5 Qts. in it and the synthetic is diluted to about 45%. I ran out of time, but I intend to run the car on stands some more before I put it on the ground to test the transmission under power.

Eventually I'll do another drain-and-refill and that should take the Synthetic "contaminant" level down to +/-20%.

Just to possibly help someone else down the line, I'll continue posting updates. Hopefully it will come to a happy ending that doesn't involve removing, rebuilding (again) with even more parts needed, and re-installing!

Lynn