T310mlr

[OldRedMack]

Did they put different gear sets in this transmission for dumps and semis?  Mine started life as a semi, but with a double frame, 44s, and 4.42 we bought it and converted it to a dump.  In GA we are at 64k gross on tandems.  Even after the engine upgrades with way more power, this transmission just doesn't seem to transfer power right too me.  I know what Mr. Wild will have to say about it, and with our other trucks being fuller's I tend to agree, but I dont want to give up on this transmission yet.  

[Ahubbard]

I am not sure what you mean by transfer power. But I think that transmission has a real low low like 26:1. I looked it up once on ratios it is similar to my rto-14909MLL road ranger. There is a lot of gears in the low geared area and the reverse is geared low too. My truck is a dump but started out as a concrete mixer. I think the lowest gear is to walk with a curb machine when pouring concrete. I know my dump works great under a milling machine. Similar to an 8ll but extra low in the low gears.


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[Ahubbard]

Wish I had multi speed reverse...


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[41chevy]

Are you talking about highway speeds or general road manors?  What is the rear ratio

[Mack Technician]

Spent phone time with The Burrens (Roland) last week crunching numbers on drivetrains before he purchased another rig. We calc’ed every gear (in his current CV713 AI-370 following your mod recipe) range against his engine and figured out, with mods, he needed to be 4.17, which he isn’t.  4.17 hit every sweet spot perfectly in the speed ranges he frequents. It also let him run 75 at a sensible RPM. Mack dived too low on diffs because of the AI issue. 

He’s selling her and already bought a New Volvo, 11 liter. Looks like a nice set up. He got his 2,000 lbs payload back by dropping to 11. Everything he spec’d with a large engine (13 liter platform)overweighted him 2K past the CV713 weight. Notch on the belt for ol’CV. 

Run your numbers with 4.17 and see how you come out. 

As for the resident T critic......he’s trolling you right now waiting on the opportunity, I think I see the dorsal 🦈 fin sticking out of the water. 😆 

Edited April 25, 2020 by Mack Technician

[OldRedMack]

On 4/24/2020 at 10:22 PM, 41chevy said:

Are you talking about highway speeds or general road manors?  What is the rear ratio

General road manors, it's not near as bad in the high range and have plenty of top end speed.  But in the low range it feels like the gears are to close together.  You run the rpm up where the truck wants to shift at and then you have to wait until wheel speed slows to get it to mesh right.  The 4.17 makes sense.  How do you run those numbers?

[Mack Technician]

You think something’s letting go in the transmission? Maybe check the magnets? 

I used the driveline calculators they have online. There’s a bunch. 

[OldRedMack]

I dont think anything is letting go, it's done this the whole we have owned it and I'm the only 1 that drives it.  I guess it wouldn't hurt to pull the plugs and refill, maybe previous owner put in wrong fluid?  Any idea on the right trans fluid? Warm weather climate in GA. 

[Mack Technician]

80W-90 convential or 75W-90 synthetic 

 

Usually wrong oil messes with you in cold temps. Like the thickness of cold conventional oil won’t squeeze out of the synchro plates and you get a winter grind on the first sync shift. Even then if you cycle it a few time before moving the truck you can squeeze it out and avoid grind. 

 

What tires you running? Gears are a game, you have things too low you will be shifting like a bandit.

 

 

This is one calculator I often use.....

https://wellertruck.com/roadspeedcalculator/

 

If Huddard's right you are really deep on the bottom, a standard T310 is 13.81 on the lowest hole.

Edited April 27, 2020 by Mack Technician

[OldRedMack]

24.5 on the tires.  The low low is really low, slower than all of our 8ll double lows, which is great when we are milling like ahubbard said.  My problems are 1-4, even loaded unless I'm climbing a hill I usually go 1-3 and skip 2nd. Then starting out empty I go to the high side and put it in double low then shift to low then 5-6-7-8.  The high side of double low is in a range between 2nd and 3rd gear.  Shifting like that seems to be the smoothest where it feels like all the gear steps are setup correctly.  Even doing a rolling stop loaded it slides right into the high side double low nice and smooth and takes right off shifting smooth thru high side low and 5-6-7-8.  

[Ahubbard]

 

I found this online. Hopefully this helps. These ratios are real similar to my 9LL

 

 

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[Ahubbard]

They might be a little blurry because they are screen shots of some weird pdf site. Here is the regular M. Ratios more like a 8ll.


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[OldRedMack]

Comparing the 8ll to the 310mlr, would the difference in ratios really feel that different? Would that be enough to drive me insane, because all of my driving previous to this truck was all 8ll.

[Ahubbard]

They look real similar except the low lows. My Mll trans is same ratios as the 14909all below in your pic. The 310mlr and 9LL Have almost exact same ratios. I have 4.42 rear as well. I was paying attention to my driving after thinking about your question. I find that I don’t rev real high in the lower gears. Actually kind of lug a little until I am

On the high side.

 

I was thinking back and I wasn’t a fan of how this trans shifted when I still had my etech in front of it. Seemed like in the lower gears it didn’t respond well enough to lug it like I do now. Had to lay into it a little and get the rpms up to have enough power to get her moving. Then was too fast for next gear shift. Just like you describe. The mechanical e7 changed my opinion of the tranny all together. Has the low end grunt now to drive it in the right rpm. Maybe Mack technician is on to something with a different rear ratio. (Although I recommend full mechanical e7 swap).

 

 

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[OldRedMack]

That's part of the problem, if you don't run up the rpm this trans does not want to go into gear.  

[david wild]

Shifts better if it was behind something green or silver and screams/drips, god forbid unlike a fuller which will shift at any RPM you try to low ball the RPMs you'll look like a idiot. on another note boat anchor biz is going strong . 

[OldRedMack]

Lol, I've been waiting for you.  Cant argue with you tho.  I can jump in all of our other trucks and not miss a beat, then get back in this truck and it's like I've never driven before. I was just holding out hope that I was doing something wrong and someone could show me the light. 

[Mack Technician]

Are the other trucks deep in the rears? Mid 4’s?

Larger displacement engines may tend to have a lower number on the rear, in the upper 3’s, because they can. Mack had to go mid to upper 4’s because of AI torque issue. The expectation was your going to rev the heck out of it because of it not having low end torque. They say so in the AI engine manual...page 18. 

“The changes are more extensive and visible for the AC engine which is used in linehaul applications at governed speeds, than the AI/AMI engine which is used in vocational applications at higher governed speeds.” They saw how crumby the low end was. 

The further into 4 you go the tighter the shift becomes especially on the low range. The number of MPH gained by in a 4th gear may be 4mph @4.64. The same 4th gear may gain 6mph when the diff is 3.86. The lower your gain the harder your shift. 

Ex- take your overdrive trans and drop a 3.86 diff in and your top speed gain from 1300 to 2000 RPM is 32 MPH.

take the 3.86 rears out and drop in a 4.64 and now the 1300 to 2000 RPM OD gain is reduced to 27 MPH. 

You may have tight shift windows, esp on the bottom, esp loaded going up a hill with a short span of gains between shifts. 

Macks a challenging shift. I have to move the Log Dogs stick pretty fast to get my grabs with the 4.35. 

The deepest ratio Roland had between modern trucks he was scoping was a 4.10 ratio. 

If your skipping groups of gears loaded then you’ve overcome the need for a deep rear end when you modified the engine for more HP and torque. 

Edited May 2, 2020 by Mack Technician

[david wild]

I like Mack trucks but there are just some things that you get wrong and that's it, when your wrong your wrong and should quit while your ahead, since Mack does not build manual trans anymore I guess they figured out you can't beat the guys that just build rears and trans. great little engines, cheap to run, we had a couple E9s I wasn't impressed but they did the job and then moved on to someone who thought they were better, we ran Big cam 4s and had no problems keeping them cool and others could not get across town, we had L9000 fords they held up great and the steering was the best, had Marmons they were great, hell we had a Astro, was like driving a go cart with the screaming jimmy under the cab so I have thoughts on what works and what does not for us, and that is my point FOR US, might be fine for some others but not for what we did in the past, I started with a Diamond T then on to a B61, 673 turbo and triplex and bought first new KW in 77 so we have been there, now we haul mostly high and wide and prefer not heavy only because no one pays for weight and the permits cost way more for weight and not so much for just oversize so my thoughts are based on my experience.      

[OldRedMack]

22 hours ago, Mack Technician said:

Are the other trucks deep in the rears? Mid 4’s?

Larger displacement engines may tend to have a lower number on the rear, in the upper 3’s, because they can. Mack had to go mid to upper 4’s because of AI torque issue. The expectation was your going to rev the heck out of it because of it not having low end torque. They say so in the AI engine manual...page 18. 

“The changes are more extensive and visible for the AC engine which is used in linehaul applications at governed speeds, than the AI/AMI engine which is used in vocational applications at higher governed speeds.” They saw how crumby the low end was. 

The further into 4 you go the tighter the shift becomes especially on the low range. The number of MPH gained by in a 4th gear may be 4mph @4.64. The same 4th gear may gain 6mph when the diff is 3.86. The lower your gain the harder your shift. 

Ex- take your overdrive trans and drop a 3.86 diff in and your top speed gain from 1300 to 2000 RPM is 32 MPH.

take the 3.86 rears out and drop in a 4.64 and now the 1300 to 2000 RPM OD gain is reduced to 27 MPH. 

You may have tight shift windows, esp on the bottom, esp loaded going up a hill with a short span of gains between shifts. 

Macks a challenging shift. I have to move the Log Dogs stick pretty fast to get my grabs with the 4.35. 

The deepest ratio Roland had between modern trucks he was scoping was a 4.10 ratio. 

If your skipping groups of gears loaded then you’ve overcome the need for a deep rear en

d when you modified the engine for more HP and torque. 

1 with fuller 9L and 4.64, 1 with 8ll 4.64, 1 with 8ll 4.42, 1 with 8ll and I'm guessing mid to high 3s cause that truck will run 90mph, 1 with a super 10 and low 4s.  I really like the super 10, but with no deep reduction it will wear your leg out under the milling machine.  The quick shift doesn't bother me, I have had to learn how to let the jakes hit between shifts. I have no doubt this truck could probably use a taller gear, but if the trans is still a pain, is it worth it?  I've talked to other guys who say there t310mlr shifts nice and easy, so if I need a rebuild and it costs 7k or I can get a fuller for $3,500.  I hate to give up on the mack trans, but I feel like the $ is making the choice for me.

[Mack Technician]

Performance & satisfaction before loyalty, swap it.  

If you know other T3 trans are doing better for a buddy, and you drive it and agree yours has an issue......I’d pull the trans top cover and polish the spalling off the shift shafts. Not a terrible job to undertake and costs virtually nothing in soft parts. Maybe I can get an amen on here, or maybe others haven’t had it, but anyone who rebuilds a number of these knows how choppy and pitted the fork rail wear-outs can get. 

Do one thing for me though?......please, give T3 a proper funeral for all her hard work. May need six good Pallbearers or four fairly stout good ol’boys to lift the trans. Find out where Wild Dave docks his 14’ fishing boat and dump her right into the driver’s seat. Burial at sea. When he extracts the boat from the lake bottom the trans needs to say “FREE BOAT ANCHOR” spray painted across the side. 

Edited May 3, 2020 by Mack Technician

[Mack Technician]

Oh heck!...Did you knock out the stick’s  double walled shift boot in the cab floor!?!? Forgot about that. Those are trouble makers for shift, Mack had us cut them out (existing ones) and they quit making them double walled. They meant well, to reduce noise and heat transfer, but they were so stiff it caused shifting issues, especially up here. It would hit -25 and guys would have the sticks return to center neutral on their own while driving. 

[JoeH]

My DM used to have rears so low you could put it in 1st direct (2 stick trans) from a stop with no clutch and it'd click right in no grinding.

[OldRedMack]

19 hours ago, Mack Technician said:

Oh heck!...Did you knock out the stick’s  double walled shift boot in the cab floor!?!? Forgot about that. Those are trouble makers for shift, Mack had us cut them out (existing ones) and they quit making them double walled. They meant well, to reduce noise and heat transfer, but they were so stiff it caused shifting issues, especially up here. It would hit -25 and guys would have the sticks return to center neutral on their own while driving. 

No, going to have to check on that.

[david wild]

14 foot boat ??? not here, maybe yard full of Helicopters that do float (ex coast guard)  to busy selling repurposed Mack trans as anchors to have a boat.