| Author | Message | ||
| Tim (165.121.128.84)
Rating: N/A |
Hi Folks, I have a MCI 5A with 4-speed manual (double clutch) transmission. I’m stuck being the only one in the family able to shift the rig and want to change it over to automatic. Has anyone converted a MCI 5a with a 4speed manual transmission to an Allison MT644 automatic? Is this do-able without any major headaches? Any ideas what I’ll need for additional parts besides the transmission to make the swap? Does anyone know where I might find a MT644 or if any other automatic transmission will fit? Thanks in advance. Tim ’66 MCI-5A 8v71 w/4 speed stick! | ||
| Frank Allen (205.188.208.39) Rating: N/A |
Think about it before you do it , you will loose 2mpg and trim 7 or so off the top speed , all that so your wife can drive and if she is like most she wont drive anyway. oh yes the engine will run hotter too, forgot that part Frank Allen 4106 | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Tim - The MT644 is the only automatic that will fit if you keep the 8V71. If you decide to do a complete powertrain swap, then the 6V92TA / HT-740 is the other comb that fits the space available. This is a pretty common powertrain in later MCIs, Eagles, Prevosts, and a whole bunch of T-drive Transits (Gillig, etc.), and can easily be bumped up to 350 hp, or about 75 more than you currently have (if your engine is the stock 8V). Might actually be less expensive to buy an whole transit bus with this powertrain from an auction, swap out what you need, maybe even be able to change the power assist steering to an integral one from the donor, and perhaps the bigger brakes, too. If you go the 6V92 route, you'll encounter some clearance problems with the turbo, but nothing that's not insurmountable. As Frank pointed out, your fuel mileage will suffer some, but top speed should remain the same, as these are direct drive, not angle drive where there's a loss. Now it's time to ponder the possibilities. . . HTH, RJ PD4106-2784 Fresno CA | ||
| Rodger Manecke (Rodger) (69.21.80.23)
Rating: N/A |
Tim, My 35' Prevost Champion (no tag) probably is similar to an MC5 in curb weight and differential gear ratio. It has an 8V71 eng. Allison MT644 combo, with a drop box between trans and differential. A drop box, mounted forward of the differential, is necessary because the engine to ddrive axle dimension is too tight for an automatic transmission. This eng/tranny combination works fine for me. Over the past 40,000 miles,running coast to coast and border to border including about 1/3 mountain driving, mostly towing a 3,000 LB Honda Accord, I've averaged 7.9 mpg. I can get near 10 mpg on flat land if I keep the speed below 60. That includes running the 7KW diesel genset for about 180 hours. My typical weight with full fluids and loaded for a trip is 29K to 30K pounds. At 1800 - 1900 rpm, my preferred cruising speed, I get 58 to 63 mph and a shade under 75 mph at 2000 rpm. On the upgrades my target rpm is 2000. 2000 rpm yields a little over 50 mph in 3rd gear and about 33 mph in 2nd. The original owner had the transmission conversion done by Dean's Coach in Durham, NC. He said the cost was in the neighborhood of $12K. This was in approximately 1994. I consider this MT644 to be a "semi-automatic" because on upgrades, the trans usually downshifts too late to keep the rpm above 1800. Hope this helps. Rodger | ||
| RANDY FULKERSON (Rwf) (66.82.208.1)
Rating: N/A |
Tim, I've done this swap many times. If you are mechanicly inclined and have a place to do it, this is something that you should be able to do yourself. I have a 1979 MC5C with a little bit too much corrosion in the body that I am considering parting out. It has a very good MT 644 transmission. If you are interested or have specific questions about doing a swap, give me a call at 660-287-2980 I'd be glad to help. Randy | ||
| neil (148.78.243.24)
Rating: N/A |
I have a Mc5 and we put in a 647. It works great, we get 7MPG and still cruise over 70. Just be careful who yu have put it in. The Guy who put mine in was not very professional about it. If you have a place to work do it your self. It is not brain surgery. You just cut out the crossmember under the transmission and make a strap to bolt across where it came out. this only serves to hold the frame together at that point. you can buy all the spacers that go between the engine and tranny, and have a good drive shaft shop make a new drive shaft to fit.You will need a cooler for the tranny. I would use a water to oil cooler so that the engine coolant cools the tranny oil. Be sure to put in a tanny guage so you know when to stop and let it cool. It should never get over 225 deg. mine never runs over 180. A 692 AND EITHER A 647 or 740 would be a better deal as you would bet a cleaner running engine and a little more power. However the 92 will run much hotter that the 71 so you would have to put in bigger raidaters and fans to make this drivable. Neil | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Wow, one of the neat things about busing is that you get to act weird. This includes learning how to safely operate the coach, including the proper way to shift gears. Crunch, crunch! Seems to me another way for you to fix the problem is to simply teach the rest of the family to double clutch your crash box 4 speed tranny. Yep!, make it a family affair. You can do it. Even I relearned how to shift for myself in my bus, and if crazy Henry to do it (left handed) soosss can your family. Bet the teanagers would go for it quickly. Do not sell your kids and wife short. I actually had an ex-girl friend who when asked if she could shift a Fuller RTO-910 Roadranger she answered Yes and do YOU (me) need lessons?  Carry on. | ||
| Johnny (63.159.185.73)
Rating: N/A |
"Wow, one of the neat things about busing is that you get to act weird. This includes learning how to safely operate the coach, including the proper way to shift gears." Oh...then I guess I'm missing something, since I already knew how to drive a crash box going in. Seriously, I drive an F-800 rollback with a Clark 5-speed crash box at work, & have also driven a Spicer 5+2 (my bus), an Eaton 7-speed (70's GMC C-50 gasser), & a "mystery" 6-speed (FL70 Business Class). I'm amazed (but probably shouldn't be) at the number of people I deal with who simply have no clue how to operate ANY manual transmission! | ||
| Paul Tillmann (Paultillmann) (205.188.208.39)
Rating: N/A |
I too, Johnny, am amazed at how many people can't drive a manual, especially young people. I finally had to switch my very small fleet of crew vehicles to automatics. Not only can't people drive a manual but it is becoming increasingly more difficult to even purchase manual transmissions anymore. A manual transmission is slowly but surely becoming an option as the automatics are becoming standard equipment. About two years ago I went to a driver training school to get my Class A CDL and was astonished that there were students that NEVER spent a minute driving a manual transmission anything, much less an 80,000 pound rig!! I learned how to drive a manual at 9 years old on my grandfathers old 53 Chevy farm vehicle and haven't owned an automatic yet (I'm 46 now). Sign of the times, I guess........ Paul | ||
| Johnny (63.159.197.191)
Rating: N/A |
I once had a passenger (about a 20-year-old female who drove a red slushbox New Beetle) riding in the F-800 (with her car on the deck--talk about overkill). She was amazed I could shift without the whole vehicle jumping. I guess her boyfriend who "knew how to drive a manual shift" really DIDN'T know how to drive a manual shift. I shift it pretty smoothly, if I do say so myself. I actually had someone else express amazement that a 2001 anything (this was a Ford F-550 diesel--another rollback) was available with a manual transmission. She thought that everything had an automatic. Depressing.  | ||
| C. Ray Powell (Raypowell) (152.163.252.163)
Rating: N/A |
Neil, What engine do you have in your MCI 5? And how does it do in the mountains with the 647? Thanks C RAY |