mmaupin Posted August 22, 2015 Share Posted August 22, 2015 Hi All,I am very new to the Mack world and somewhat of a diesel novice as well. Other than all of that, I am fairly mechanically inclined.Recently purchased a 59 Mack B61T that has been restored. First wondering if anyone recognizes this beast and can provide some history on the refurbishment?Secondly, I really want to make it a driver; roadworthy and dependable. To do this, I am thinking about changing out the engine and transmission to something more modern with good parts and service availability. Any suggestions for engines and transmissions?Thanks in advance. I am sure to have a hundred other questions as I move forward with this project.Regards,Mark Maupin 1 Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted August 22, 2015 Share Posted August 22, 2015 that truck was for sale in upstate Ny last year. Lake George or Glens Falls I think, then it ended up out west or maybe was still in Ny and sold by a broker out west? Quote Link to comment Share on other sites More sharing options...
Joseph Moody Jr Posted August 22, 2015 Share Posted August 22, 2015 Welcome Quote Link to comment Share on other sites More sharing options...
mrsmackpaul Posted August 22, 2015 Share Posted August 22, 2015 Gudday Mark welcome to the dog house mate I think you can still get all the parts you will ever need for the motor and trans fairly easily if you want to make it quicker you could change the diff ratio and it would be fine I thinkproviding you dont haul big loadsPaul Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 22, 2015 Author Share Posted August 22, 2015 that truck was for sale in upstate Ny last year. Lake George or Glens Falls I think, then it ended up out west or maybe was still in Ny and sold by a broker out west?I actually bought the truck from a vintage auto dealer in Denver, Colorado.Gudday Mark welcome to the dog house mate I think you can still get all the parts you will ever need for the motor and trans fairly easily if you want to make it quicker you could change the diff ratio and it would be fine I thinkproviding you dont haul big loadsPaulPaul,No big loads at all.According to the data sheet, with the TRD 67 transmission and the RAS rear axle with a 4.25 ratio, top speed is 57 MPH @ 2100 RPM. I think my ratio is a 5.14 which makes a top speed of 47 MPH.... Yikes!I want to go 65 to 70 MPH with ease and get rid of the air start system.Mark Quote Link to comment Share on other sites More sharing options...
rustydog Posted August 23, 2015 Share Posted August 23, 2015 I actually bought the truck from a vintage auto dealer in Denver, Colorado.Paul,No big loads at all.According to the data sheet, with the TRD 67 transmission and the RAS rear axle with a 4.25 ratio, top speed is 57 MPH @ 2100 RPM. I think my ratio is a 5.14 which makes a top speed of 47 MPH.... Yikes!I want to go 65 to 70 MPH with ease and get rid of the air start system.MarkDo you mind if I ask what it cost you Mark?? Quote Link to comment Share on other sites More sharing options...
Bobby j Posted August 23, 2015 Share Posted August 23, 2015 Welcome from another Georgia boy...........Bobby j. 1 Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted August 23, 2015 Share Posted August 23, 2015 Nice truck! I'm in the Commerce area, what size rubber on the truck? I'd deff. keep the original engine/trans. Quote Link to comment Share on other sites More sharing options...
Joe Ditchkus Posted August 23, 2015 Share Posted August 23, 2015 Nice truck. Like others said I would personally keep the factory drivetrain. The duplex is common and avaible used reasonably. triplex and quadbox will work also with driveshaft work.It is a reliable driveline. 1 Quote Link to comment Share on other sites More sharing options...
41chevy Posted August 23, 2015 Share Posted August 23, 2015 Welcome! Nice B.I would definitely keep the stock power pack. Remember the last B rolled out in 1965 and there are still a ton out there working and being used almost daily. Can't get more dependable than that.Change gearing for the speed you want, up grade to an Alternator and have a ball with it. Paul 1 Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
mmaupin Posted August 23, 2015 Author Share Posted August 23, 2015 Do you mind if I ask what it cost you Mark??$13,500 Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 23, 2015 Author Share Posted August 23, 2015 Nice truck. Like others said I would personally keep the factory drivetrain. The duplex is common and avaible used reasonably. triplex and quadbox will work also with driveshaft work.It is a reliable driveline.Okay, that sounds good about keeping the factory drive train. I want to comfortably cruise at 65 to 70 MPH. I have a metal lathe and can do the drive shaft work. Can you direct me to some specifics of changing to a triplex or quad box?Regards,Mark Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 23, 2015 Author Share Posted August 23, 2015 Nice truck! I'm in the Commerce area, what size rubber on the truck? I'd deff. keep the original engine/trans.It has the 10 - 20's Quote Link to comment Share on other sites More sharing options...
Joe Ditchkus Posted August 23, 2015 Share Posted August 23, 2015 You will need to find an overdrive duplex,triplex or quadbox. Pretty straight forward from there.Or you can find a carrier with a bit higher ratio than you now have. I would stay in the 4.00+ ratio if you go higher than that it might not pull very well.These old trucks were not designed for high speed when produced as speed limits were most likely top of 55 MPH. Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted August 23, 2015 Share Posted August 23, 2015 Have you tested the top speed yet? Here's a speed calculator. http://www.csgnetwork.com/rearendgearcalc.html Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 23, 2015 Author Share Posted August 23, 2015 Have you tested the top speed yet? Here's a speed calculator. http://www.csgnetwork.com/rearendgearcalc.htmlSeems to top out at about 45 MPH. When I have another set of eyes in the shop with me, I will mark the tire and drive shaft and figure the differential ratio from that.Regards,Mark Quote Link to comment Share on other sites More sharing options...
mowerman Posted August 23, 2015 Share Posted August 23, 2015 just go to a wrecking yard and get a rearend outa something else,,,,single drive,, lotta them around,,,doesnt have to be a mack,,,anything will work.good luck,and welcome... bob Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted August 23, 2015 Share Posted August 23, 2015 Seems to top out at about 45 MPH. When I have another set of eyes in the shop with me, I will mark the tire and drive shaft and figure the differential ratio from that.Regards,MarkDid you check it with a GPS? Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 24, 2015 Author Share Posted August 24, 2015 Did you check it with a GPS?Yes, checked with a GPS as the original speedo is not working.Now with the great help, information and advice of this forum, plus some information from oldmacksrus.com, keeping the original drive train is viable . A couple of folks recommended putting in a triplex or quadbox tranny. I am really starting to like that idea. Running the numbers, at 2100 RPM with a 5.14 rear end and a quadbox with a fifth gear high speed ratio of 0.66, that puts my top speed at 76 MPH. If it is a 4.63 rear end, the top speed would be 84 MPH. Either would be workable for me. The heaviest load I will be pulling is ~6000 Lbs.The big question is will a TRQ-720 transmission bolt right up to the Thermodyne 673? From one of the posts above, Pedigreed mentioned some driveshaft work would need to be done. Wondering what else?If anyone has direct knowledge of this type of transmission swap and would like to chat about this or any other suggestions, my phone number is listed below.Regards,Mark678-350-1514 Quote Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted August 24, 2015 Share Posted August 24, 2015 I'd gear it to run 60/65, you'll still want some torque, 1 Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted August 24, 2015 Share Posted August 24, 2015 the quadbox will work. youd want an 18 speed double over or at least a 20 speed single over for what you want. you have to take the emergency bell and brake off the back of the trans for a quad as its a really tight fit without the cab crossmember moved back. not a big deal if you already have maxi brakes Quote Link to comment Share on other sites More sharing options...
mmaupin Posted August 24, 2015 Author Share Posted August 24, 2015 I'd gear it to run 60/65, you'll still want some torque,That sounds reasonable.Hopefully, someone can give me some specifics of the mechanical fit up of the TRQ-720 to the Thermodyne.The TRQ-720 has fifth gear ratios of 1.95LL, 0.91LS, 0.78D and 0.66HS, so with that type of gearing, it would give me ultimate flexibility.Regards,Mark Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted August 24, 2015 Share Posted August 24, 2015 it will fit, if you take the e brake off the back. also might have the change the bell housing on trans. some had 3/8 bolts in the bell on the engine and some had 7/16. not a big deal. Quote Link to comment Share on other sites More sharing options...
Freightrain Posted August 24, 2015 Share Posted August 24, 2015 Nice truck. Why are you removing the air start? Too much hassle for you? I'm one of the dumb guys that is working to put it ON my truck. I ain't too smart sometimes............... well a lot of times.I'd look for a double over triplex or quad. That will give you the long legs you desire. Finding a 4.00 double reduction gearset is hens teeth. Mine came with 4.62 and that is pretty fast compared to most of the B models I know of. Just bobtailing, you can run it 65-70 and it won't break a sweat. 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted August 24, 2015 Share Posted August 24, 2015 I have a double OD quad and 5:74 gears, top speed is about 67 @2100. I have 22" rubber though. Quote Link to comment Share on other sites More sharing options...
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