Vladislav Posted February 23, 2022 Share Posted February 23, 2022 I always suggested that T200 series trannies utilized synchronizers for the range shift starting from T2090 9-speed and further to multy-speed units such as T2100, T2110. T2130 and T2180. T2060 and T2070 (and T2080) have much deeper 1st speed in the high range so my guess was they didn't use synchro because you don't shift Lo-Hi on a highway and only ocassionally when on a job site. So less times of the parts to couple, less wear and not much need in the expensive synchronizer. But recently I met a listing (on evil bay) representing synchro repair kit which was described to be used in T2080(B). I made more googling and other sources (mostly related to PAI parts sellls) mentioned Mack synchronizer and mating gears suitable for T2090 and so on but T2080 and T2080(B) either. Were those 8-speed trannies equipped with similar synchro as 9 or 10 speeds had? Or starting from a certain time maybe? Unfortunately I don't have a book particulary for T2080. The reason I ask is there's an 8-speed unit for sale locally. I could grab it for parts but saw no reason since I already catched 2 T2070 and have 2 T2090 to rebuild. But if there's synchro in that T2080B I would be much more exited to add it to the inventory. Thanks in advance for any input. Vlad Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/ Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 Hello Vlad, I just went to my library. The 2080B looks to have a synchro in the back box. I posted the shift pattern and the pic with my finger, is me pointing to the synchro. I posted pics of the 2080 just to show the difference. the picture with all the books is also in my library. I have 3 sets of 200 series books, and 2 sets of 300 series books, as well as Mack rears, drive shaft and many others... I will post any info that I can to help you in the future. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490104 Share on other sites More sharing options...
Vladislav Posted February 23, 2022 Author Share Posted February 23, 2022 Wow! Many thanks for the quick answer and immediately scanned images! From the diagrams you posted both T2080 and T2080B have synchros. The unit of my desire is a long compound housing with outside shift cylinder. So it's definitely a "B". There was a tag in the cab of that truck which also said that. And there was a stick off the transmission with spinning trigger. Funny thing I already purchased that cab and the stick was laying inside of it. So the only thing I need to add is the tranny The truck was a 1998 DM concrete mixer which worked mostly in the city. So my hope is the drivers seldom shifted the ranges and the milage was not exremely high either. I may take the top cover off for the inspection but you can't see condition of the synchro teeth without taking it off and apart. On the other hand the cost of the tranny turns out as a half of a new PAI synchro set if count together with the mating gears. Or nearly twice more than its scrap value. So seems worth making a try. Good collection of the manuals you have! I also stocked up a little. Have T2090/T2100 book, T2110 and T2070. But missed a chance grabbing one for 2080. Kept in mind it should be similar to T2070 and T2060 with only different compound box gears (which are of the same ratio as T2090 BTW). But now seems a worthy bit of info slicked off from my attention. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490116 Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 I dont believe there is a synchro in the straight 2080.. might there be a cover on the back box that you can pull to inspect it? the blue book in the picture covers a wide range of tranny's,.. as you know, the main 5 speed box is basically the same, the aux. boxes give each tranny it flare... P.M. me anytime if you need info.. Good chance I have a book.. and I have been know (by my wife) to buy a book, just to answer a question here... I know I will use them at some point. jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490117 Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 Of course.... its very easy to stand the tranny on it's nose and pull the back box off. just keep a rope with a loop in one end , handy so you can lasso the counter shafts... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490118 Share on other sites More sharing options...
Vladislav Posted February 23, 2022 Author Share Posted February 23, 2022 What also put me off the tracks is diagrams someone shared on here a long while back. If you look at the first pages of these two the T2090 sheet mentions a synchro in the list of options. And T2080 sheet doesn't. I have similar files for the whole T200 series and everything higher than 8 speeds mentioned synchro with lesser speed units don't. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490120 Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 I see what you are saying, I guess beacuse the 2080 has a range button and it is shifted using double clutching, or you stop and put it into high split when you are out of the hole you were in, and the (B) has the rotary shifter which requires a synchro... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490128 Share on other sites More sharing options...
Vladislav Posted February 23, 2022 Author Share Posted February 23, 2022 7 minutes ago, Joey Mack said: I dont believe there is a synchro in the straight 2080.. might there be a cover on the back box that you can pull to inspect it? the blue book in the picture covers a wide range of tranny's,.. as you know, the main 5 speed box is basically the same, the aux. boxes give each tranny it flare... P.M. me anytime if you need info.. Good chance I have a book.. and I have been know (by my wife) to buy a book, just to answer a question here... I know I will use them at some point. jojo Actually there were 3 sets of gears for the main boxes utilized in T200 series. One for long steps of nearly 70% for work with Maxidyne engines. Those had 5.24 1st gear and 0.60 overdrive. This was achieved by "fast" constant mesh gear set. The use was T2050, T2060, T2070(B) and T2080(B). Another combo was for 40% steps and took place in T2090. 1st gear of 2.79 with 0.71 overdrive. Intersting point the overdrive gear set was the same parts as in the 1st lot used (T2050 etc) But slower constant mesh made the overall overdrive ratio slower (0.71 vs 0.60). Adding a second compound to T2090 Mack turned it into T2130 and T2180. One more main box gear combo was used to get nearly 30% steps in T2110 10 speed unit. The constant mesh was again lowered a bit and the overdrive ratio became 0.77 (still having the same gears on the main shaft/counter shaft). Basing on this design an interesting modification T2110B was made. It had its special feature of one more "low" set of gears installed in place of the reverse gear in the main box. So you have 6 front speeds on the stick and this tranny was offered in a "B' mod only since reverse needed to take place somewhere and was moved to the compound box. Speaking the compound box there were 3 variations of its low range ratio. The fastest was used in T2060 so the only gear of the main box (1st) became lower when the Lo range shifted (and the tranny obtains 6th speed). The medium took place in T2070 setting 2 gears off into the lower range (5+2=7 speed). And the lowest of 3.84 was used in T2080 making 3 gears lower than the Hi range so 3+5=8. All the highway trannies starting from T2090 used that same compound gear set of 3.84. 10-speed and 11 speed units achived a bit slower constant mesh ratio again so 5 speeds formed the Lo range. I put all that info together to show that Mack made a whole family of different transmissions using only 3 sets of gears in the main box (even with only one gear set for overdrive) and 3 sets of gears for the compound box. Don't know who may be interested in these facts but was going to share them systematically for general use. 1 Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490132 Share on other sites More sharing options...
Vladislav Posted February 23, 2022 Author Share Posted February 23, 2022 (edited) 15 minutes ago, Joey Mack said: I see what you are saying, I guess beacuse the 2080 has a range button and it is shifted using double clutching, or you stop and put it into high split when you are out of the hole you were in, and the (B) has the rotary shifter which requires a synchro... jojo That's what I would suggest using logic, the same as you did. But looking the pages of the manual you posted the T2080 short compound box also shows the synchro installed. Edited February 23, 2022 by Vladislav Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490133 Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 ok.. You are obviously a well studied person when it comes to this topic and the specs you know.. Truly impressive.. I may not be much help, but I will continue to try, and then I learn from you... Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490135 Share on other sites More sharing options...
Vladislav Posted February 23, 2022 Author Share Posted February 23, 2022 8 minutes ago, Joey Mack said: ok.. You are obviously a well studied person when it comes to this topic and the specs you know.. Truly impressive.. I may not be much help, but I will continue to try, and then I learn from you... Jojo You already helped alot. And it's quite a common case when even very clever person may be achived in stupid situation just not knowing some key point. From the post you shared about engine repairs etc it clearly seemed to me that your knoweledges were deep and skills very impressive. But the fact you are eager to share the info and help others is very appreciated. Nice to discuss with you. It's already late time at me. I'm off to a sack 1 Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490141 Share on other sites More sharing options...
Joey Mack Posted February 23, 2022 Share Posted February 23, 2022 Good night sir, thank you for your kind words... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/69282-t2080b-synchro/#findComment-490143 Share on other sites More sharing options...
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