Red Horse Posted July 28, 2012 Share Posted July 28, 2012 My B has a 237 with a Duplex and 6.67 rear. I would like to change the rear ratio but good CRD-62's are like hen's teeth. So I'm thinking, easiest thing is to put an OD Triplex or Quad in it. Any opinions. A lot of experienced people tell me that the Duplex can't handle the torque of a Maxidyne and I do use the truck on occasion (35,000lbs and occasionally a bit more)Added benefit of the trans. vs. a gear set change is I don't minimize the off road capability of the truck.By the way, this truck was built as a B-60X, I believe original owner pulled the gas power train and put a 711/Duplex in it. then the guy I bought it from put a 237 Reman in it that had 10,000 miles on it. Hence "gas engine rear gears". Quote Link to comment Share on other sites More sharing options...
bullhusk Posted July 29, 2012 Share Posted July 29, 2012 My B has a 237 with a Duplex and 6.67 rear. I would like to change the rear ratio but good CRD-62's are like hen's teeth. So I'm thinking, easiest thing is to put an OD Triplex or Quad in it. Any opinions. A lot of experienced people tell me that the Duplex can't handle the torque of a Maxidyne and I do use the truck on occasion (35,000lbs and occasionally a bit more)Added benefit of the trans. vs. a gear set change is I don't minimize the off road capability of the truck.By the way, this truck was built as a B-60X, I believe original owner pulled the gas power train and put a 711/Duplex in it. then the guy I bought it from put a 237 Reman in it that had 10,000 miles on it. Hence "gas engine rear gears".I don't think puttin in a single OD trans is gonna give you very good speed with that ratio, I would check the salvage yards and see if you could pick up a 5 speed Maxi an a nice 4.17 rear out of the same truck.( I'm assuming it's a Maxi engine and a single axel that you have in the B60 )BULLHUSK Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted July 29, 2012 Share Posted July 29, 2012 double overdrive 18 speed quad with a double disk clutch would probably get you decent road speed since your runnin true 24'' rubber. even with that slow rear you might get 62-65 mph out of it. id stay away from a triplex as quads are more common for parts and with your 237 and rear you might not get a split low enough to use it off roadin or with some weight. Matt Quote Link to comment Share on other sites More sharing options...
Red Horse Posted July 29, 2012 Author Share Posted July 29, 2012 double overdrive 18 speed quad with a double disk clutch would probably get you decent road speed since your runnin true 24'' rubber. even with that slow rear you might get 62-65 mph out of it. id stay away from a triplex as quads are more common for parts and with your 237 and rear you might not get a split low enough to use it off roadin or with some weight. MattMatt, 62/65 would be great-right now I'm at like 54. Plus its not just the top end. With a 237, I could also get "around town" at lower RPM's. That is take advantage of the Maxidyne concept and consistantly run in the lower RPM band. So a double OD is a TR?????BillH- I hear you on the 5 spd 4.17. But part of the "attraction" of this old dude is that big rear double reduction rear with the torque rods. Don't want to lose that. Quote Link to comment Share on other sites More sharing options...
Green Dash Posted July 29, 2012 Share Posted July 29, 2012 Overdrive's end with a zero i.e. TRD107 is a direct and TRD1070 is an overdrive. The wiki button above will take you to some excellent, detailed info. Here's the link to the tranny pdf.http://www.bigmacktrucks.com/index.php?/tutorials/article/37-b-model-transmission-data/ Quote Jim Link to comment Share on other sites More sharing options...
BrianDzimitrowiczJr Posted July 29, 2012 Share Posted July 29, 2012 Red Horse, didn't you have that truck at the the 2012 ATHS show in Springfield Mass? if so i think you were parked a row over from us with it Quote Brian1959 B61T Link to comment Share on other sites More sharing options...
Red Horse Posted July 29, 2012 Author Share Posted July 29, 2012 Red Horse, didn't you have that truck at the the 2012 ATHS show in Springfield Mass? if so i think you were parked a row over from us with it10-4- I had a conversation with you and Maddog. By the way-did you see "supershowrigs.com? Go to "ATHS National Show" then "pictures". You guys are on page 3-I'm on pg. 4.-fourth row. There are pix of trucks I never saw!~GreenDash- thx-I've seen that before-but what is the double 'O" version Maddog references? TRQ 7220?? Quote Link to comment Share on other sites More sharing options...
BrianDzimitrowiczJr Posted July 30, 2012 Share Posted July 30, 2012 lol i thought we did. i'm gonna have to check out that web site. there were so many trucks there i could have spent the entire day saturday looking at trucks if it didn't get rained out. definitely a good show Quote Brian1959 B61T Link to comment Share on other sites More sharing options...
BrianDzimitrowiczJr Posted July 30, 2012 Share Posted July 30, 2012 I know whoever spec'd my B61 out had specd' it pretty heavy. it has a 29,000 lb. double reduction rear without trailing arms with a 5.17 hogs head. i keep forgetting but i want to measure the the axles out of a smaller rear, say a 23000 because it sure does look like i could swap in a hogs head with a lil more road speed. say a 4.28. idk just my 2 cents Quote Brian1959 B61T Link to comment Share on other sites More sharing options...
Green Dash Posted July 30, 2012 Share Posted July 30, 2012 GreenDash- thx-I've seen that before-but what is the double 'O" version Maddog references? TRQ 7220??It appears they use only one zero regardless of whether it is a single or double overdrive. it also lists all 20 gear ratios, even the redundant ones, on the 18 speed version of the Quad. Quote Jim Link to comment Share on other sites More sharing options...
terry Posted July 30, 2012 Share Posted July 30, 2012 It appears they use only one zero regardless of whether it is a single or double overdrive. it also lists all 20 gear ratios, even the redundant ones, on the 18 speed version of the Quad. No 0 is a single overdrive in the back box, all triplex and quads are overdrive in the back box, A 0 like in a TRQ7220 is overdrive in the front, so there is your double overdrive. terry 1 Quote Link to comment Share on other sites More sharing options...
Red Horse Posted July 31, 2012 Author Share Posted July 31, 2012 No 0 is a single overdrive in the back box, all triplex and quads are overdrive in the back box, A 0 like in a TRQ7220 is overdrive in the front, so there is your double overdrive. terrySo for sure a TRQ 7220 is what I'm looking for to capitalize on my low rear ratio? Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted July 31, 2012 Share Posted July 31, 2012 yup, TRQ7220 is a double overdrive 18 speed. the 20 stands for 2 over. overdrive in the front and rear box. 1 Quote Link to comment Share on other sites More sharing options...
terry Posted July 31, 2012 Share Posted July 31, 2012 So for sure a TRQ 7220 is what I'm looking for to capitalize on my low rear ratio? Yes any 72 series with a 0 at the end is a double overdrive, either a TRT or a TRQ. Terry 1 Quote Link to comment Share on other sites More sharing options...
Green Dash Posted July 31, 2012 Share Posted July 31, 2012 No 0 is a single overdrive in the back box, all triplex and quads are overdrive in the back box, A 0 like in a TRQ7220 is overdrive in the front, so there is your double overdrive. terryyup, TRQ7220 is a double overdrive 18 speed. the 20 stands for 2 over. overdrive in the front and rear box.Yes any 72 series with a 0 at the end is a double overdrive, either a TRT or a TRQ. TerryThanks for clearing that up.. Quote Jim Link to comment Share on other sites More sharing options...
Red Horse Posted August 1, 2012 Author Share Posted August 1, 2012 Thx guys- now to find one Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted August 7, 2012 Share Posted August 7, 2012 in the 50's they made a 20 speed direct so not ALL quadboxes are overdrive. the early ones were direct in 5th and slow. a single overdrive was a TRQ7210 i believe and a double was a TRQ7220. it wasnt a zero, its an O for overdrive. 7210 is 1 over, 7220 is 2 over. could all this means nothing til you drive it. driven quite a few 10 speed direct mack transmissions that people have swapped gears and back boxes and you just knew it was an overdrive something or other. some shift fine and other wouldnt not split right because of 5th gear. this was probably due to the boss yellin at the mechanic going ,'' i dont give a shit, make it work somehow, that truck has to be out of here tomorrow!'' Quote Link to comment Share on other sites More sharing options...
leversole Posted August 7, 2012 Share Posted August 7, 2012 Be aware they also made differing final OD ratios! Here are two different quads compared with the Triplex I have... Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted August 7, 2012 Share Posted August 7, 2012 I don't think you will be happy with the road speed even after a double over quad box is installed. Your rear end is way slow. For example A 5.73 rear end with a double over quad will get you to about 63 mph at 2100 rpm. Thats kinda slow with a fast rpm. If your just trucking to shows or under 60k gross weight,Your maxidyne would love a 3.86 rear and a 5 speed. Not only will you get highway road speeds but better mpg and less shifting. Just my .02 Will a early 70s diff not drop in your housing??? Quote Link to comment Share on other sites More sharing options...
fifth wheel Posted August 7, 2012 Share Posted August 7, 2012 All 72 series triplex and quadruplex compounds are overdrive.Triplex direct TRT72, single ODQuadruplex direct, TRQ72 single ODWith overdrive main box,Triplex over TRT720, double ODQuadruplex over, TRQ720, double ODThe 2nd 2 in the number is variation in input shaft (spline size, single /double disc)There is a duplex (TRDX72), 10 speed with only 7 progressive gears. Around here it was called a dead stick, that was a few years ago.The transmission you need is a overdrive quad for the speeds you need, but not the best choice against a 237.FW Quote Link to comment Share on other sites More sharing options...
Freightrain Posted August 7, 2012 Share Posted August 7, 2012 Why not find complete housing with 4.xx gears? Gotta be a scrapped out B model you can get the whole thing from cheap enough? Unbolt the spring hangers and slip the whole thing in.This is what I sold Mike:...............(less tires) Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
Red Horse Posted August 15, 2012 Author Share Posted August 15, 2012 Why not find complete housing with 4.xx gears? Gotta be a scrapped out B model you can get the whole thing from cheap enough? Unbolt the spring hangers and slip the whole thing in.This is what I sold Mike:...............(less tires)F-train- its a double reduction CRD -62 with torque rods-tough animal to find. Quote Link to comment Share on other sites More sharing options...
Red Horse Posted August 15, 2012 Author Share Posted August 15, 2012 All 72 series triplex and quadruplex compounds are overdrive.Triplex direct TRT72, single ODQuadruplex direct, TRQ72 single ODWith overdrive main box,Triplex over TRT720, double ODQuadruplex over, TRQ720, double ODThe 2nd 2 in the number is variation in input shaft (spline size, single /double disc)There is a duplex (TRDX72), 10 speed with only 7 progressive gears. Around here it was called a dead stick, that was a few years ago.The transmission you need is a overdrive quad for the speeds you need, but not the best choice against a 237.FWHi Fifth Wheel. didyou make it to Hudson. Why don't you think a TRQ7220 is a good choice for a 237? Again, snowballs chance in hell I can find a higher gear set for a CRD-62. P & S had some and they sold them all to some guy from Canada. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted August 15, 2012 Share Posted August 15, 2012 I think the problem is that a 237 has 900ftlbs of tq where the old 673 or 711 had under 700ftlbs tq. The quad was rated to mid 700 ftlbs if I recall? It will work for a hobby truck and many did it back in the day but it will be at its limits, the genral thought was if done drive it like you own it... Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted August 15, 2012 Share Posted August 15, 2012 i dont know,i know a few 237 and 18 speed quadboxes driving around and they seem to work fine as long as your not hot rodding it. if you beat it enough the 237 with smoke the clutch. if you found a double disk clutch 18 speed quadbox i think youd be happy. the 237 doesnt have the bigger torque like a 300 plus or 350. the quads and triplexes wont hold up behind those. you will end up splittin 5th gear and most likely busting the case with a little bit of lugging. i know they made TRQ77 series quadboxes that were 20 speed direct and i know i have seen a TRQ72 series that was direct in 5th before. Quote Link to comment Share on other sites More sharing options...
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