Crown clutch info

[syntaxterror]

Hi looking to get info on Crown clutch set up. I have a rto 910 that came out of a crown that I am going to put in my Thomas 3800 t444e. I have been told that Crowns had hydraulic clutch and would like to get some specks on the size of the master and slave cylinder. I know International uses a mechanical clutch set up and I might use that system. Just trying to look at all the options as a hydraulic system might be easier to work with.

 

[Crown_Guy]

Hi looking to get info on Crown clutch set up. I have a rto 910 that came out of a crown that I am going to put in my Thomas 3800 t444e. I have been told that Crowns had hydraulic clutch and would like to get some specks on the size of the master and slave cylinder. I know International uses a mechanical clutch set up and I might use that system. Just trying to look at all the options as a hydraulic system might be easier to work with.

Crowns have never used hydraulic clutch systems. Always simple pull rods and bell-cranks. Why does it matter anyway if you're taking the RTx-910 out of a Crown and swapping it into another bus.

The clutch components are all part of the bell housing and have nothing to do with the transmission itself. If you intend to use the bell housing and transmission combo from the Crown and swap into another engine/bus you're likely to find bigger problems than you realize at this point in time. First thing to remember is that the Crowns had horizontal engines with the bell housing modified to accept that and allow for the normal entry of the clutch actuating shaft. There was also "Push" and "Pull" clutch configurations that changed during the years.

There's a lot to consider and I admit I don't have all the answers but you should know that all bell housings are not created equal. You may find it easier to mount the transmission to your existing bell housing, if it's the right SAE size of course, and make your own system to actuate the clutch. You may get lucky and can use whats already in place...... But it's almost never that easy. Mr. Murphy simply Loves projects like this.

Another thing you may not have considered is that the 910 is likely longer than what's in your bus currently for one thing, and also heavier as well which is why the Crowns all had supports attached to the frame rails that were positioned mid-way on the transmission to support the weight so the bell housing wasn't carrying all that weight alone. You've much to deal with as I'm sure you'll find out about real soon.

Bottom line is, don't worry about what Crown may or may not have used, your problem is a clean slate situation with making the stand-alone RTO-910 fit onto your engine/bell housing combination. That should keep you occupied for a while. The Crown is less than a zero consideration in this equation and has nothing to do with it.

 

[syntaxterror]

Thanks for the info. I was under the impression crown used hydraulic clutch set up and was wanting info on the bore size of the slave and master cylinder to see if that was a better option. Right now I am in the parts gathering phase. I need to get a sae 2 clutch housing, clutch and flywheel and maybe input shaft. :Thanx:

 

[s2mikon]

When I was helping my cousin install a 13 speed into his crown we had to re use his bell housing because the one from the upright engine was clocked slightly different. It also had mechanical linkage. Check in truck wrecking yards because some Mack's used cable clutches with air assist. If you do it right you will like it. Finding all the parts is going to be maddening.

 

[Crown_Guy]

Thanks for the info. I was under the impression crown used hydraulic clutch set up and was wanting info on the bore size of the slave and master cylinder to see if that was a better option. Right now I am in the parts gathering phase. I need to get a sae 2 clutch housing, clutch and flywheel and maybe input shaft. :Thanx:

Ahhhh, The input shaft. Almost forgot about that tactical nuke. There are more than one sizes and the clutch, flywheel, and transmission input shaft all have to match. If they don't and you have to change the trans input shaft that's a major, major, operation and you might as well plan on doing a rebuild while you're in there because it all has to come out just to get the input shaft assembly out. Like I said Murphy is rubbing his hands and looking over your shoulder.

 

[rossvtaylor]

I've also never seen a hydraulic clutch in a Crown. My "atomic" Crown, with a rear engine 8V71, has an Eaton T-905 transmission and here's a bit of video about adjusting the clutch in that, in case that's of interest:

https://youtu.be/MMmI7f4eVk4?si=Nzs1PYYsE58OcvBY

 

[Booyah45828]

I'm not familiar with the rto910 specifically, but a large number of big rig transmissions can swap the input without any transmission disassembly. There's a bearing retainer held on with a ring a bolts, that once removed, the input can be wiggled out.

I'd be surprised if the rto910 is different, but I've been surprised before.

You guys are correct, that there are spline counts, diameters, pilot diameters, lengths, etc. to account for regarding an input shaft. To buy one separate it might be more then what was paid for the transmission.

 

[s2mikon]

You may want to look on the F*** f-250 forums. I think I remember some there talking about it. May have just been that talk. Installing a class 8 transmission behind a class 6 engine will require some research.

 

[Crown_Guy]

You may want to look on the F*** f-250 forums. I think I remember some there talking about it. May have just been that talk. Installing a class 8 transmission behind a class 6 engine will require some research.

I was wondering the same thing actually. The "9" is for designed limit of 900 ft/lbs input torque. Fuller makes many transmissions with lower input torque specs for smaller engines. mid-range torques of "6" are common. For instance, RTx-610 (10spd) RTx-606 (6 spd) etc. They've recently changed the nomenclature describing the various transmissions and I admit I haven't kept up with the naming changes but the units remain the same no matter what they call them.

I'd suggest doing some deep dive research into the extremely extensive offerings from (now) Eaton-Fuller for all manner of torque and number of gears they offer. Of course you can find all this used somewhere once you know what to look for. The RTx-910 may really be overkill and inappropriate for the size engine you want to mate it to. That was my first thought when I read your post, but hey, to each his own. After all Murphy needs something to do.

 

[syntaxterror]

Once again thank you Crown Guy. The rto 910 is what I have so I will run with it. The main reason for the upgrade is my AT545 trans. I have the orian system to get more power out of the t444e but right now keep it at 210 as to not damage the trans. I also have a non overdrive spicer 5 that would be the same amount of work to install.