Slab Hauler Posted August 26 Share Posted August 26 Have an RD886SX with a little 300, 5spd, direct/lo/rev compound aux, 80k rears wearing 12r24 rubber. solid walking beam suspension. 20K fronts. Triple frame. The truck is NEVER on the Hiway, and never will be. So get that out of your mind. A typical day is moving a roughly 175-180k gross load about 2 miles on flat ground with maybe 1/4 mile of that in reverse. Anyway, the 5spd is on it's last legs. Don't know the history before we got it. Going to go Allison when this happens, just not sure which parts we are going to need. Any suggestions? Already know custom driveshaft. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/ Share on other sites More sharing options...
mechohaulic Posted August 26 Share Posted August 26 can't recommend parts; but sure hope the BMT crew gets to see a picture!! RD886 SX . any model with the 8 in it (B-81 / DM 800/ RD800 ) has my interest and vote. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557642 Share on other sites More sharing options...
Slab Hauler Posted August 28 Author Share Posted August 28 There might be some floating around. I am told this truck originally came from the Sparrow's Point blast furnace. Now it is in Ohio, in yet another mill. Next time it's "clean" i'll take a couple. Mill work is filthy Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557745 Share on other sites More sharing options...
tjc transport Posted August 28 Share Posted August 28 We don't mind dirty truck pictures. That just proves it really is a work truck. And I fully understand mill work is filthy. A "quick" 1/4 mile trip into the mill grounds for a load of 3/4 to 1 inch recycled Slag and I have to wash the truck off cause it looks like I drove across the mud flats at 50 mph!! Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557746 Share on other sites More sharing options...
67RModel Posted August 28 Share Posted August 28 On 8/26/2024 at 8:14 AM, Slab Hauler said: Have an RD886SX with a little 300, 5spd, direct/lo/rev compound aux, 80k rears wearing 12r24 rubber. solid walking beam suspension. 20K fronts. Triple frame. The truck is NEVER on the Hiway, and never will be. So get that out of your mind. A typical day is moving a roughly 175-180k gross load about 2 miles on flat ground with maybe 1/4 mile of that in reverse. Anyway, the 5spd is on it's last legs. Don't know the history before we got it. Going to go Allison when this happens, just not sure which parts we are going to need. Any suggestions? Already know custom driveshaft. I would say a lot more information is needed. First off, what year is the truck? If its mechanically injected and no ECM then you are probably limited to the Allisons that require no electronic controls. Would any of those even be suitable for this application? Then you run into mounting / crossmember issues. Are 80k rears planetary drive? Might run into ratio problems but probably not in this use case. I'm guessing you probably never get above 15 mph on flat ground but definitely something that would have to be checked....ratio of your rears. There might be other things in play but honestly I can't see how this would be worth it. Just get another TRXL 107, or overhaul the existing one and put it back in. You probably never come out of 1st direct anyway. With everything involved, an Allison swap would be hard to justify to travel 2 miles per day on flat ground. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557747 Share on other sites More sharing options...
The Heinz Posted August 28 Share Posted August 28 An Allison swap into a truck originally built with a manual is something I have never looked into, nor has the dealership I work for. There's a lot of moving parts in a question like this. I know the bare minimum you would need the correct adapter plates for the flywheel, torque converter bolts, oil cooler setup that depends greatly on application/chassis/transmission, different engine mounts, coolant hoses, shift setup that depends greatly on what Allison you have and truck interior, trans output yoke, yoke nut/bolt, and a lot more. I think it would be more financially friendly to either fix or replace with an identical transmission, Allisons alone are very expensive, not to mention the other parts and the work you'd have to do to get the setup to work. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557749 Share on other sites More sharing options...
Slab Hauler Posted August 28 Author Share Posted August 28 No ECM, it is a mechanical engine. Truck is a 1984. 15 mph on the loaded trip would be pushing it, there is probably 8 RR crossings along the trip. Multiple stop/ intersections. Newton's 1st law. And don't forget the nutjobs on their carts zipping all over the place. I should clarify, a 2 mile trip 20 to 25 times a day 6 days a week. Yes i know mounts, cooler, shifter, going to be fab work. that is not really intimidating. Getting the right flywheel adapter and torque convertor now that is where things get hairy. Bellhousing not so much, they are mostly either type 1 or type 2. I was leaning towards an ht740 or 745 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557758 Share on other sites More sharing options...
Slab Hauler Posted August 28 Author Share Posted August 28 2 of the other trucks on this haul are Allisons. 1 is a KW, Cummins ISX 525, Allison 7spd with 4 speed aux box, Sissou planetary rears, Chalmers suspension combo. it's a pretty modern truck (dam emissions). We ordered it new as a prime mover. The other is a big 1982 Pete 353 with a KT (de-rated) and an Allison CBLT754 with a 4 spd aux, 60K planet Rockwells, Hendrickson solid walking beam. Anyway, bec of the start/stop and backing the drivers pretty much wrestle over the autos. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557760 Share on other sites More sharing options...
JoeH Posted August 29 Share Posted August 29 Cable shifted HT740 is probably your best bet. Do you need a pto? The port on the 740 is literally on top, which can be a pain in the @$$ on space. I'll snap a picture of the HT740 I have sitting behind a spare engine from a 2000 MR688. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557797 Share on other sites More sharing options...
JoeH Posted August 29 Share Posted August 29 Flywheel housing and flywheel are likely your biggest obstacles. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557798 Share on other sites More sharing options...
Slab Hauler Posted August 30 Author Share Posted August 30 Yea flywheel/flexplate was what I expected to be the biggest obstacle. Torque convertor for a similar hp/tq rated engine should be close. Do not need a pto. A pic would be awesome. The water pump went out of it yesterday, so it's down for the time being. Yesterday was also the last day moving steel for a couple weeks. Have some other things to address, new front springs, bushings, hangars. Once the hood is back on and it's outside i'll get a pic or 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557825 Share on other sites More sharing options...
JoeH Posted August 31 Share Posted August 31 Pictures don't show you much other than a plethora of wires. Double check, but I don't think there's any TCM. Just data sensors for the engine ECU. Trans temp, neutral safety switch, VSS, etc. You can see the PTO plate on top. Your best bet on donor will be a trash truck or an Oshkosh front discharge concrete truck. I have a 2000 MR688 cutoff with the HT740 cable shift, my 2003 MR688 has an HD4560 which has all sorts of electronics onboard. Pictures not posting, I'll try and get them up.... 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-557852 Share on other sites More sharing options...
Popular Post Slab Hauler Posted September 3 Author Popular Post Share Posted September 3 Big boss Just told me this morning, he wants to go with an 8LL. Pfft, well alritey then. Thanks for the input guys. Anybody want to take bets on that changing in a month or two? LOL 1 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558034 Share on other sites More sharing options...
JoeH Posted September 4 Share Posted September 4 Short of finding a good 5 speed that matches, staying with a manual trans of some variation makes the most sense. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558058 Share on other sites More sharing options...
Popular Post Slab Hauler Posted September 11 Author Popular Post Share Posted September 11 On 8/26/2024 at 10:52 AM, mechohaulic said: can't recommend parts; but sure hope the BMT crew gets to see a picture!! RD886 SX . any model with the 8 in it (B-81 / DM 800/ RD800 ) has my interest and vote. 7 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558357 Share on other sites More sharing options...
tjc transport Posted September 11 Share Posted September 11 that almost looks like a new york sanitation tractor. ... except all theirs that i have seen or heard of were 3406 cat with allison automatic. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558371 Share on other sites More sharing options...
Slab Hauler Posted September 12 Author Share Posted September 12 I know where there are 2 of them. 60k rears. Clean as a pin. Would not be afraid to register them and put on the road. Would love to have them, guy seems non-committal on selling them. yes no yes no, then ghosts for a month. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558410 Share on other sites More sharing options...
mechohaulic Posted September 12 Share Posted September 12 as the saying goes" pictures worth thousand words " ;; those pictures are more then a thousand words for me :: more like speech less. what a beautiful lookin piece of machinery. thanks for the photo. Quote Link to comment https://www.bigmacktrucks.com/topic/74498-allison-swap/#findComment-558420 Share on other sites More sharing options...
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