m16ty Posted February 11, 2016 Share Posted February 11, 2016 I've had a Spicer 1241-C trans for awhile and I'm thinking of putting it behind my 12 speed in my RD822sx. Does anybody know if this would be a good combination? I really only want it for a lower 1st gear but the OD will also be nice because the truck tops out right now around 60mph.It has some bearing issues I've also got to deal with before the install. Does anybody know if parts are readily available? Quote Link to comment Share on other sites More sharing options...
m16ty Posted February 12, 2016 Author Share Posted February 12, 2016 The trans is a air shift. The model tag doesn't have a P though. Could be somebody swapped the top cover to air shift at one point.From my research, only difference in the air and manual is the top cover. Quote Link to comment Share on other sites More sharing options...
Freightrain Posted February 12, 2016 Share Posted February 12, 2016 I've heard horror stories about parts for boxes like this. I don't know. My little 6241 box is working pretty well. The output is just starting to get damp after running it down the highway. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
6368 Posted February 13, 2016 Share Posted February 13, 2016 I had one in my KW with a 3406b behind a rto14613. i thought it was great.... just the right amount of gears. I put new bearings the box maybe four years ago. cost me a couple hundred bucks. Don't remember where i got it but a kit was easy to find. Quote Link to comment Share on other sites More sharing options...
m16ty Posted February 13, 2016 Author Share Posted February 13, 2016 Well I need a mainshaft. Bearing went down where the main shaft and input shaft go together and it ate the bearing surface on the mainshaft.With a little searching I was able to find a mainshaft for $500. I don't think that is too bad. Quote Link to comment Share on other sites More sharing options...
steve p Posted February 14, 2016 Share Posted February 14, 2016 air shift and stick shift have totally different internals 1 Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted February 14, 2016 Share Posted February 14, 2016 Yes they do Quote glenn akers Link to comment Share on other sites More sharing options...
m16ty Posted February 14, 2016 Author Share Posted February 14, 2016 Does anybody know how to time everything when putting it back together?I took it apart Friday and noticed some marks on the gears but didn't think anything of it. Talked to a guy yesterday and he said the gears have to be timed during assembly. He said he put one together one time without timing it and it roared like crazy, he ended up taking it to a trans shop to fix it.I don't really see what there is time unless it has something to do with balance or something. Quote Link to comment Share on other sites More sharing options...
mrgumby Posted February 14, 2016 Share Posted February 14, 2016 (edited) http://www.tremec.com/anexos/SPTS001-0306_130.pdfit might give you some idea Edited February 14, 2016 by mrgumby Quote Link to comment Share on other sites More sharing options...
rcall31060 Posted February 14, 2016 Share Posted February 14, 2016 (edited) Call Camerota Truck Parts in Enfield, CT. Talk to Sal Camerota. He'll be able to help you.http://www.camerota.com/ Edited February 14, 2016 by rcall31060 Quote Link to comment Share on other sites More sharing options...
m16ty Posted November 28, 2016 Author Share Posted November 28, 2016 I'm back on this project after a long wait. I've just been too busy to fool with it and with winter coming on I have some time. In my search for the correct yokes to match my driveline, I ended up calling TTC ( the people who are now building the Spicer trans). Talked to a guy that seemed very knowledgeable on auxiliary transmissions. He told me I was crazy putting a 1241 behind a E-9, 12 speed and that it would never hold up. This has given me pause and wondering if I need to rethink this. Anybody with real world experience with a Spicer 1241 care to chime in? The issue I called him about is my current driveline has 1880 yokes and the biggest available for a 1241 is a 1810. Quote Link to comment Share on other sites More sharing options...
Brian Blaylock Posted November 30, 2016 Share Posted November 30, 2016 I would not bother putting a 1241 behind a E-9 with a 12 speed I used to drive on with 4.17 rear ratio it would run a lot faster than 60 mph and would idle through parts in soft ground Quote Link to comment Share on other sites More sharing options...
david wild Posted November 30, 2016 Share Posted November 30, 2016 Yep Yep Yep it will not hold up, check the input torque rating, it is very low, if your looking for reduction the fuller AT1202 is the way to go, if you want a overdrive also then you will have to go to one of the new 3 speeds and I have not seen one. your mack will eat that spicer lunch. I assume this is for your 800? 1 Quote Link to comment Share on other sites More sharing options...
Hobert62 Posted November 30, 2016 Share Posted November 30, 2016 Do you want the lower first gear for a parade gear? Or a working gear. There is a different outcome between the two uses. Quote Link to comment Share on other sites More sharing options...
m16ty Posted November 30, 2016 Author Share Posted November 30, 2016 David, Yes, this is for the RD822SX. I've been looking at the AT1202 and I may end up going that route. The OD gear would be nice but I can live without it, it tops out now at around 60 mph. I mainly need a lower forward speed. The 12 speed trans is already plenty low enough in reverse, my brother says reverse will be so low with a auxiliary that it will actually go forward, LOL. This truck is going to be tasked with pulling a 100 ton trailer and I hope to upgrade to a 200 ton setup in the future. On 11/30/2016 at 8:11 AM, Brian Blaylock said: On 11/30/2016 at 8:47 AM, david wild said: On 11/30/2016 at 8:54 AM, Hobert62 said: Quote Link to comment Share on other sites More sharing options...
Hobert62 Posted November 30, 2016 Share Posted November 30, 2016 Strictly my opionion but...If its going to be used like that you defiantly do not want to be second guessing anything in the drive train. 1 Quote Link to comment Share on other sites More sharing options...
david wild Posted December 1, 2016 Share Posted December 1, 2016 If your 800 has 24 inch rubber you will not enjoy driving it much faster than what you got, the 1202 will cut your speed by half, we run in the low side all the time, really makes a world of difference with big loads, unless your bent on going 70 mph, at which point you will need pyscho help anyway. If you were using 46 rears you could go to a DT hub, that would give you 3 to 1 wheel end reduction, that along with a 1202 and you can wrinkle a drive tire sidewall if you don't spin. we run as much as 60k+ on our tandem drives with that setup and still can spin out. 60 mph cut in half by 1202, now cut that by 3 with DT hub, you can move 750k on site with one truck, 500+ on the road. we pulled that nasty hill coming out of Farmington NM, 440k one truck with 1202 and hubs, slow but no problems. 1 Quote Link to comment Share on other sites More sharing options...
m16ty Posted December 1, 2016 Author Share Posted December 1, 2016 Yes, I'm running 12.00-24. Only thing the extra speed would be good for is going to the job empty. It's not a deal breaker either way. I don't have to have it but I would use it if it was there. I'm running 65k rears. The more I think about it, I may just sell the 1241 and pick up a 1202. Quote Link to comment Share on other sites More sharing options...
kscarbel2 Posted December 1, 2016 Share Posted December 1, 2016 In your case, reference the RD8 column. 1 Quote Link to comment Share on other sites More sharing options...
m16ty Posted December 2, 2016 Author Share Posted December 2, 2016 I wish I could find a 1202 new for $2,240. Quote Link to comment Share on other sites More sharing options...
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