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HeavyHaulinMac

Maxitorque T2060 Air leak

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I have a 94 MR 690S cabover with a Maxitorque T2060 Trans. and a Leach 2RII rear load refuse body... Minimal access to transmission.

My problem is a broken/ leaking air line over the transmission that is for the range selector. In low range the air leak increases, high range the leak is there but less. This line is bundled with 3 others that all go to fittings and are OK. The broken one does not have any fittings or another half of a line it would have been connected to nearby. Truck seems slow to change range but not that bad as range selector is only for low reverse and LO-LO. 

Does anybody know where this "extra" leaking line is supposed to go?

Also on the passenger side there is 2 plugs into the housing. which one is to add gear lube?... would like to change it. 80W-90 I suppose?

Pics attached

thanks for any help

20190928_124054.jpg

20190928_123148.jpg

Edited by HeavyHaulinMac

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Can't help with the line, but the big plug is fill, the small is a magnet.    terry:MackLogo:  Reread your post, the line you said is broken might an exhaust line from the air shifter.

Edited by terry

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Two lines which are attached to the top cover supply air to the shift cylinder inside the rear compartment. Actually mounted on the inner side of the cover (or even cast together with it). Not almost sure but the rearmost is to shift in high since high range is direct in compound and direct is done via straight connection of both main and compound main shafts. So shift fork should go foward for that and it means air gets to the rear to force it. No matter, I might be wrong. Easy to determine removing the line and check for air pressure.

The line which goes from the bracket is supply. There's a plated hose, it provides air from the chassis. The unit on the bracket reduces pressure to suitable figure to switch gears. The line from it goes to your flipper switch on the stick. The switch shifts air to one of those two lines to the cylinder and connects the other one to atmosphere at the same time.

T2090 and other transmissions which allow pre-select have additional unit with air lines for locking air flow when the stick is not in neutral. T2060, 2070 and 2080 have just simple 3 line setup as described above.

Vlad

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+1 on possibly a vent line. Could have a leak in the range selector cylinder. What happens is one side is hi other side is low. If the oring between the two fails the air will bypass from selected range to vented range. Thus, your "leaking" vent line, because the unused side is switched to the vent.

I have an 8ll that did this, but the orings were fine, but the disc that is the "combination cylinder" was cracked in 3? places.

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Not sure what access is on your t2060, the 8ll is easy to fix from the rear of the trans.  We have 1988 RD690S with a t2070? that we had to take the range selector out the top because we had to take off the rear mounted PTO for repairs and a countershaft dropped. Had to jack the back of the cab up as far as we could plus we conveniently had a hole in the floor between the seats. Was doable, but it needed 2 or 3 sets of hands at times.  Not sure how your access will be.

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Couldn’t it be just in the shifter knob?

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Shifter handle was replaced with new about 2 years ago so I doubt there is a problem with that. We've had this truck for quite a while and I do not recall ever noticing this leak. I'm sure you guys are correct in saying it is a vent line but shouldn't it stop after everything equalizes? From the information thus far it sounds like a fault internally from the cylinder. Just for clarification this is a garbage truck to get an idea of the access to the tranny. Only access is from underneath with a "ceiling" about 8 inches above it.

Thanks so far for all the info.

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Worst case scenario, if shift cylinder needs repair, does transmission need to come out/ or cut a hole in the floor of the body?

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Does the cab tilt forward on an MR? I guess the trans is under the trash body?  I'd hate to say you need to pull the trans, but you'll need more than 8 inches of head room. May have to lift the body off or drop the trans.  12 inches you might be able to get away with it if you're skinny...

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Yeah trans. Is under trash body... was thinking of taking forward body mounts off and a couple hydraulic hoses & wires then seeing if I can tilt the front of the body up high enough and securing it well enough to get in under there and do the repair. If not I'll probably just cut a hole in the floor of the body and see what happens from there lol

This is pretty close to what I have going on 32b261a82793faaf1f6cf686ca35ee6c.jpg

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You're on the right path, just make sure you put blocks between the frame and body before you go under there.

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One last question:

I went to get some oil to chance in the transmission, and the guy behind the counter told me 75w-90 synthetic is proper for a T2060. Does that sound rite?

Ive looked online and saw people using 50w mineral? Or 80w90

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75W-90 GO-H/S synthetic or 80W-90 GO-H conventional gear oil is good.

Don't do 50W, it will kill that series of Mack transmission.  50W is for Fuller transmissions.

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Wow thanks you guys are great I owe you a night's worth of drinks!

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1 hour ago, HeavyHaulinMac said:

Wow thanks you guys are great I owe you a night's worth of drinks!

Sent from my SM-G892A using Tapatalk
 

Well what was the problem? Did you get it fixed?

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In fact 8 inches could be enough. I'm not almost sure but the idea is to drive off all the cap screws of the compound top cover and try getting it up. It would go but there is a shift fork which wouldn't allow to remove the cover. Even possibly it would but I would say 50:50, didn't measure its length. But it seems there could be another way. The shift cylinder is a cast boss on the down side of the cover. The cylinder itself is a hole drilled in the boss and closed with two covers at each end attached with bolts. The air leak you expect is through a gasket of one of those or through the piston seal. Telling all that I'm about sure you'll be able to remove the covers having 8 inches gap. Possibly the piston too.

Another point if you suppose the cylinder as the reason of leak I would try locking every air line going to it for a check. Pretty sure much easier than removing the top cover of the tranny. Find some suitable plug such as piece of rubber, steel ball etc, unscrew the fitting, put the plug into and reattach. Than put your shifter in operation and watch for any difference. Do one line at a time.

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Haven't done the repair yet, need to have a little less going on as I still do a few loads a week with this truck. I am definitely going to do that little bit if diag. Vlad. said before I tear it apart just to be sure. Shifter is only like 2 years old so I doubt there is a fault with that, but you never know. I will definitely post the repair I find to be the solution.

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