dayradebaugh Posted January 7, 2017 Share Posted January 7, 2017 Hopped in my B81SX with a quad the other day. Temp was about 20 deg. F. Main box shifted fine, but back box (4 speed) would not shift, at least easily, for about 5 miles. Would it be safe to put synthetic in this transmission? If so, what weight? Any brand recommendations? Would I need to flush out the old fluid before switching to synthetic? As you can see, am in the process of installing a Holmes 750 on the unit. Will be hooking up a PTO to the transmission, so now is the time to change the fluid, if possible. Also in the process of installing fenders on the wrecker bed, as below. Thanks for your help. Day Radebaugh 2 Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/ Share on other sites More sharing options...
terry Posted January 7, 2017 Share Posted January 7, 2017 That is pretty normal, put front box in gear back box in nuetral and let run for a few minutes, will loosen things up.I would keep the gear oil in it. terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357421 Share on other sites More sharing options...
Mack58B42 Posted January 7, 2017 Share Posted January 7, 2017 Hi Day, Nice truck - B-model wreckers are always good looking rigs. Would you like to have your truck listed on the B-Model Registry - a place to try to document all the B-models still showing signs of life? If so, you can send me your VIN via PM, or you can go to the registry website and fill in the data form, and I'll get you listed. If you're not comfortable listing your personal info, that's fine, but it would at least allow us to know that your truck is still out there.... Here's a link to the site if you'd like to check it out: http://www.mackb-modelregistry.com Thanks! Mike Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357424 Share on other sites More sharing options...
theakerstwo Posted January 7, 2017 Share Posted January 7, 2017 If the back box shifts stiff look at the linage on top of the trans for the rear box.There is some grease zerts that the two rails go thru and they may need clean and regreased. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357438 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 Guys: Terry, your procedure had occurred to me, and I'll give it a try right off. Thanks for the advice. Mike, I'm anxious to get on the registry, and will complete that procedures. Appreciate the help. Day Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357443 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 Guys: Terry, your procedure had occurred to me, and I'll give it a try right off. Thanks for the advice. Mike, I'm anxious to get on the registry, and will complete that procedures. Appreciate the help. Day Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357447 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 Hadn't thought of those zerks on top of the tranny. I'll give them some grease. They probably haven't seen grease in years. Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357448 Share on other sites More sharing options...
Maddog13407 Posted January 7, 2017 Share Posted January 7, 2017 my triplex back box shifts hard til its warm to. usually takes 15-30 minutes to get some smooth shifting out of it. greasing the fittings and rods wont hurt either Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357451 Share on other sites More sharing options...
Hobert62 Posted January 7, 2017 Share Posted January 7, 2017 Neat project. We all like pictures to look at. Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357468 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 I'll certainly post some pix when I get her painted this spring. Roughly what's left is: --install some of those rubber fender flares on the fender cutouts we did --paint it --hook up another air tank --hook up pto --for you wrecker dudes, I have to move the control handles which were originally on the side of the truck. I ran out of fender space, and will install the control handles on the surface of the wrecker bed. The geometry of these control handles should work the same, just shifted in position 90 deg. This control rod mechanism is a nightmare anyway, and explains why hydraulics caught on so fast. Should have it on the road by the beginning of the spring season. By the way, this B81 is running a 237. Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357488 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 Just test drove Terry's suggestions above and it worked fine, good enough to get me out on the road where I could really warm it up. Appreciate the suggestion. Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357491 Share on other sites More sharing options...
terry Posted January 7, 2017 Share Posted January 7, 2017 3 hours ago, dayradebaugh said: Just test drove Terry's suggestions above and it worked fine, good enough to get me out on the road where I could really warm it up. Appreciate the suggestion. I would grease it also. terry Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357511 Share on other sites More sharing options...
dayradebaugh Posted January 7, 2017 Author Share Posted January 7, 2017 Will do. It was fun walkin' the dog again with this truck. Quote Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357524 Share on other sites More sharing options...
Freightrain Posted January 9, 2017 Share Posted January 9, 2017 I always start mine and let the boxes run while building air. With my added aux, I run it in neutral and let the the front boxes run to loosen up. Neat project. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/48267-b81sx-quad-transmission/#findComment-357738 Share on other sites More sharing options...
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