jeffbyrne Posted September 1, 2008 Share Posted September 1, 2008 (edited) Hey Guys, I have been looking for a Mack to buy and later put a dump bed on but. What the heck do all the numbers and letters mean? DM, R600, RS686LS, RS, R686ST, and it seems like ther are a lot more mumbers out there too! Maybe there is a book out there that explains it! Any help would be greatly appreciated by this rookie!Regards, Joel hi wacko, in Australia we've always had a limited range of Macks available, but i'm sure the # are all the same. The 1st letter is the model followed by mayb another to denote a variation of that model. Then the 1st# is the capacity of the truck, i.e. 600 is usually lighter duty in some way than a 700 or an 800. The 2nd 2 # are the engine. In the 70's a 711 would be an R609 or 709or F609,709 etc, a 673Cwould be an R611, a 237 an R685 a truck with an END864T would always be at least a 700, F719 or R719. If there is a 4th # it is often a 4 or a 6, this is 4x4 or 6x6. The next letters are, in Aust an R is for RHD, you probably wouldnt see this much in the US. Next is an S ,T,ST,X,SX. T is a single drive, ST is Tractor, usually a light weight rear like a 34,000lb, S is like 44,000lb an SX or an RSX is usually 55 or 65,000lb rears. In Australia we have A8-FR712RST, A8 is Australian twin steer tandem drive. I think you'll find exceptions to every rule. Hope this explains a bit more. Jeffro. Edited September 1, 2008 by jeffbyrne 1 Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-21683 Share on other sites More sharing options...
HarleyD Posted March 19, 2020 Share Posted March 19, 2020 Model number cross reference https://www.macktrucks.com/parts-and-services/support/body-builders/news-and-events/new-mack-model-description-cross-reference-chart/ Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-445978 Share on other sites More sharing options...
Mcollins Posted June 18 Share Posted June 18 Hey I’m new to this page and been reading a bunch of great information. I have a question on my old rig. I have a 81’ Rd685s made in Mack Canada. Is there a way to know what the axles are and the GVW? (I would gladly take any info on that model) The door tag has the VIN and model but all the other information looks as if it was never stamped?? Thanks for the help Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553936 Share on other sites More sharing options...
terry Posted June 19 Share Posted June 19 Some close up pics on steer and tandems axles should be able to figure something out. Terry Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553980 Share on other sites More sharing options...
JoeH Posted June 19 Share Posted June 19 RD in 1981 will be a double framed R model 685 will be a 237hp Mack ENDT675 engine (The "6" above is the standard frame profile) The S after 685 indicates 6 wheel truck, typically using 44k lb rear tandem. I expect it's a Mack camelback. ST is Six Wheel Tractor, usually 34-38k rear tandem. SX is Six wheel Extreme duty rear tandem, typically 55k springs, potential to go up to 65k supposedly, or even 100k I think if i remember reading something about it once, but that would be on an RD800. Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553982 Share on other sites More sharing options...
JoeH Posted June 19 Share Posted June 19 FYI if the truck was originally operated in Canada then it may have a "Canadian spread" axle spacing, so longer camelback springs, longer driveshaft between the intermediate axle and rear axle. Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553983 Share on other sites More sharing options...
terry Posted June 19 Share Posted June 19 A RD is not always double framed, it is a deeper and thicker than a standard R model frame. I have seen single framed RD’s. Terry Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553986 Share on other sites More sharing options...
67RModel Posted June 19 Share Posted June 19 My 94 RD is a heavy single frame. I never measured it but looks like 3/8" thick. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-553988 Share on other sites More sharing options...
JoeH Posted June 19 Share Posted June 19 On the old VIN system, RD is double frame I believe. A single frame would just be an R. We have a single frame R686ST under this VIN system. On the new VIN system, there is only an RD, and it's used for both single and double frames. I had a 2001 RD688ST, which was a single frame 400hp tractor with 38k air ride. We also have 2 other RD's on the new VIN system, an '88 RD690S and a '95 RD688S. Both are double frame triaxle with 44k rears. The 690 is an EM6-300L maxidynes, the 688 is an E7-350. Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-554009 Share on other sites More sharing options...
terry Posted June 20 Share Posted June 20 I have seen old steel dashed RD’s with a single frame. Terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-554040 Share on other sites More sharing options...
Vladislav Posted June 21 Share Posted June 21 On 6/20/2024 at 2:00 PM, terry said: I have seen old steel dashed RD’s with a single frame. Terry But would be interesting to learn of which rail heigth and thickness. All R600's (not RB, RD, RS, RL) had 9" high 1/4" thick channels. Could be a single frame or with 1/4" inserts. Later RD's (along with RB's) had 10-5/8"x5/16" rails in standard configuration (could have 1/4" inserts too) and 10-3/4"x3/8" optional rails. But I don't know what early year's RD had. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/3803-what-do-all-the-letters-and-numbers-mean/page/2/#findComment-554065 Share on other sites More sharing options...
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