M939 Transmission swap

74M35A2

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Replacing all air lines on trans with stainless braid. Small lines to shift knob uprate from 1/8” to 5/32”.

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74M35A2

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Good eye! Gone. Too bad it won’t fit in your PM box. Fuller ran 2 air lines to their shift knob (one for range selector, one for splitter) silly rabbit. I ran a single line to shift knob, then split it. This split should really be internal to the knob channels, whatever. Test shift with air hose plugged in was a wood-maker. Super deep metallic “clunk” each time either button actuated.

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74M35A2

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Grabbed a new clutch pedal pad for the hydraulic master cylinder, 2010 Freightliner Cascadia. Dealer wanted $70 for the hydraulic clutch hose to include the proprietary clip, not sold by itself. NFW. Over to BMW dealer being they are both German, and away we go, in stock, same part, same use, slightly different vehicle.

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74M35A2

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Trans rear support mount came in. I think I bolt angle iron in on each inside of the frame rails to support this. Still have to study that.

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74M35A2

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Trans rear support mock up. Fits so far. Is adjustable height with spacer plates, etc... Second pic is one installed. M939 trucks set the engine and trans to the far right to clear the front driveshaft, so I may need to cut the right side of the spring support and add a frame bracket extension on the left side. No big deal.

Also pic of SAE #1 vs SAE #2. There are drawings available to determine each, but here is a clear pic of the difference. I’ll post that in a stand alone thread so it is easy for others to find. Bottom clutch housing is the SAE #1 that came with the RTO-12513 trans. Top clutch housing is SAE #2 I bought with standard mechanical clutch actuation, before I changed my mind and switched to a hydraulic clutch slave cylinder. Both of these clutch housings will be up for grabs if anybody is interested. Cheap. Fit most all Eaton / Fuller dual countershaft transmissions.

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Lukes_deuce

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Love the progress! Cant wait to see it in the truck. I know of a guy on the facebook page who put an 8LL Fuller in a m923a2. I asked to see if he had pictures/video but havent heard back. Keep up the great work!
 

74M35A2

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Yep, that was forwarded to me. I called and texted to chat about, and no response. No big deal. I’m documenting this for anybody else interested in doing the same.
 

74M35A2

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While waiting for Christmas break to perform the swap, I replaced the Eaton/Fuller splitter cylinder cover and valve on the back of the transmission, since the original had a very slight air leak. New splitter cover had tiny air flow ports for the splitter piston, so the action was much delayed compared with the original. This is probably to lessen the shock on parts when splitting gears, but it drove me nuts. I wanted it to work as fast as it did before, just without the leak, so I pulled the new cover off again, and drilled out the splitter piston air flow orifices in the new cover to the same diameter as the original cover had. Sure enough, quick splitter operation was restored. Here is a pic of said splitter cover on the rear driver side of the transmission:

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Replaced the air pressure regulator also, had a slight hiss to it. This drops pressure to 60psi for the trans range and splitter actuator pistons.

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Because the powertrain sits all the way to the passenger side between the frame rails, I just realized I'll need to put a crazy left bend in the shift rod coming up through the cab floor once above floor level.
 
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74M35A2

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Had our monthly dine-in of local members, and one guy got so excited over the 13 speed, he spilled his beer when showing me how to shift it.

Now we just need some snow to melt.
 

74M35A2

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Thanks. Yes, thread is miles long but full of details, part numbers, etc. My daughter was placed into a double-advanced curriculumn at school, so I’ve been doing hours of Algebra at home instead, 6 days a week, which has slowed truck progression. Just replaced all 12 dog bone ends, and next up is to get my LWS ring mounted, then swap the motor and trans once school lets out. Will install clutch pedal first so it is done, then do the swap.

Trans seems good to go. Updated the range and selector valves, along with a modern shift knob. All seems to function well on the run stand. Can’t wait to be doing range and splitter shifts while accelerating. I’ve never driven a RoadRanger before, should be fun. Clutch brake and all of it...
 
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74M35A2

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If I decide to sell it....

There is nothing wrong with the ISX Signature-600 I just acquired, starts and runs perfect.
 

Jbulach

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Sell it to me, I’ll wait till you get yours put in fist. Grendel’s already got way too much cool stuff!
 
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