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[Freightrain]

8 hours ago, Geoff Weeks said:

And how many souped up 3406, Big Cams and KT19's were running around pulling freight when the biggest transmissions were 1200 ft/Lbs?

Rear axles that were geared fast so the high power engines could reach triple digits and still held together with all that torque?

Those were likely all twin countershaft boxes.  This is a single countershaft.  That is why I don't like it.

I would like to put faster gears in truck so I could eliminate the 6041 box.  3.55?  I could save 250 rpm at 65 mph(1550 instead of 1800).

[Freightrain]

8 hours ago, Joseph Cummings said:

That engine was never coupled to a 5 speed from Mack. It's not a Maxidyne high torque rise engine. It was always coupled to something 9 or more speeds. If your triplex is a 2 inch input shaft and a dual disk clutch I wouldn't worry about it

2" Single disc clutch.  It is a composite disc, not organic.  If I change clutch housing to allow a dual disc I have a flywheel and dual disc clutch to use.

I found a data sheet, 315 HP, 1050 ft/lb @1400 rpm.  Not really a stretch from my 237.  Extra 100ft/lb but a few hundred rpm higher.

[davehummell]

Larry too bad your triplex wasn't a double over 13 speed you would have the road speed without changing your rearend and it looks like it doesn't have a jake if you can get one it would be a nice extra for pulling your trailer, I run a complete muffler system on my truck and if the passenger window is up I can't hear it working of course I have 70 year old ears.

[mowerman]

lol most of us are in the same boat …some of these road trucks pass me with straight 8 inch stacks and and I’m thinking my god bud how can you stand all that racket 

[Geoff Weeks]

9 hours ago, Freightrain said:

Those were likely all twin countershaft boxes.  This is a single countershaft.  That is why I don't like it.

I would like to put faster gears in truck so I could eliminate the 6041 box.  3.55?  I could save 250 rpm at 65 mph(1550 instead of 1800).

I think you missed the point. I was saying, regardless of construction, they were putting way more through the box than rated.

I was putting over 1400 though a box rated for 1100 for years, in daily use without a problem, no lube pump or oil cooler. Your 100 ft/lbs isn't even on the radar as a problem.

All I ran were organic 14" double disk clutches, even when pulling 170K!

Both items were still going strong when I retired and sold the trucks.

Far more important, is if the driveline is a good match. I am not a fan of gearing up with multiple OD and then gearing down in the back. Too much lost in heat and also you have to make sure you aren't operating the shafts anywhere near critical or cruise is at half true critical.

[Mark T]

15 hours ago, dockmen027 said:

I'm remembering that 300's and 300 Plus had larger air cleaners than the 237's, any plan for that yet?

 

Kevin in near Oneonta NY, He is mainly Mack, his shop is called All Mack. But I've seen some nice Brockway cabs come out of his shop years ago...

I would think in 2025 it wouldn't be very difficult to fit some form of K & N filter or something like that on the tip fan and duct it out from under the hood somehow.  An air cleaner for the engine wouldn't need to be much bigger than an old oil bath or something as far as real estate in the aircleaner area. They make a lot more stuff now after the diesel pickup craze than back when this was a more popular swap.

[Mark T]

3.55s with the Triplex ?  that's pretty fast even with 20 inch rubber.  If I'm not mistaken the Triplex has a little tiny overgear. So even of you didn't cruise in overdrive, 3.55s are still pretty fast in direct (I'd guess well into the 70s) 

[Geoff Weeks]

Larry, refresh my memory, what rear axle did you put in the B? Memory says it is some form of Rockwell/Meritor, but I don't trust memory anymore.

[Geoff Weeks]

28 minutes ago, Mark T said:

3.55s with the Triplex ?  that's pretty fast even with 20 inch rubber.  If I'm not mistaken the Triplex has a little tiny overgear. So even of you didn't cruise in overdrive, 3.55s are still pretty fast in direct (I'd guess well into the 70s) 

I agree, my rule of thumb was

3.70/3.73 for mid .80's OD on stand up 20"

3.55 would be ok for Low profile 22.5's

[Freightrain]

1 hour ago, Geoff Weeks said:

I think you missed the point. I was saying, regardless of construction, they were putting way more through the box than rated.

I was putting over 1400 though a box rated for 1100 for years, in daily use without a problem, no lube pump or oil cooler. Your 100 ft/lbs isn't even on the radar as a problem.

All I ran were organic 14" double disk clutches, even when pulling 170K!

Both items were still going strong when I retired and sold the trucks.

Far more important, is if the driveline is a good match. I am not a fan of gearing up with multiple OD and then gearing down in the back. Too much lost in heat and also you have to make sure you aren't operating the shafts anywhere near critical or cruise is at half true critical.

I realize the triplex will likely be fine.  Would I like something better?  Yes.  If something comes along I will rethink it.  Once I saw the data sheet, I realize it is not such a large leap in power as I first imagined.

I have a single disc clutch.  Granted, not pulling 100k+ lbs but again I would like to improve it if I can.

Yes, Rockwell.  It came with 3.70 when I bought but that was too fast for 180 HP so I swapped it to 4.10 for no cost.  Now, fast forward 10 yrs and 3.70 would have been a good choice.

Without using the OD in the 6041 box, it runs 65 @1800 rpm.  I would like to drop that to 1500(noise level drops drastically).  The 6041 runs in direct 99.9% of the time.  I only use the OD if I need to get around someone when 72 mph isn't enough with the triplex OD.

I'm sure the shafts are no where critical speed.  If the truck had 5.x-6.x gears I would be more concerned with that.

[Freightrain]

59 minutes ago, Mark T said:

I would think in 2025 it wouldn't be very difficult to fit some form of K & N filter or something like that on the tip fan and duct it out from under the hood somehow.  An air cleaner for the engine wouldn't need to be much bigger than an old oil bath or something as far as real estate in the aircleaner area. They make a lot more stuff now after the diesel pickup craze than back when this was a more popular swap.

Agree, I will get a cone KN filter for turbine.  I do want to get a paper filter instead of the oil bath.  The inlet tubes are very sloppy from all the oil film coming into the turbo.  It doesn't suck the filter dry but I would like to convert it somehow.

[Mark T]

There's so much more available now for filters.  Geeze, if you have 4.10s ?  an old 15 over (like an RTO12515) would be a great choice. a hair more overgear than the Triplex 

[Geoff Weeks]

38 minutes ago, Freightrain said:

I realize the triplex will likely be fine.  Would I like something better?  Yes.  If something comes along I will rethink it.  Once I saw the data sheet, I realize it is not such a large leap in power as I first imagined.

I have a single disc clutch.  Granted, not pulling 100k+ lbs but again I would like to improve it if I can.

Yes, Rockwell.  It came with 3.70 when I bought but that was too fast for 180 HP so I swapped it to 4.10 for no cost.  Now, fast forward 10 yrs and 3.70 would have been a good choice.

Without using the OD in the 6041 box, it runs 65 @1800 rpm.  I would like to drop that to 1500(noise level drops drastically).  The 6041 runs in direct 99.9% of the time.  I only use the OD if I need to get around someone when 72 mph isn't enough with the triplex OD.

I'm sure the shafts are no where critical speed.  If the truck had 5.x-6.x gears I would be more concerned with that.

Short shafts, the higher the critical speed. I was surprised that my stone stock driveline in my K put it well into critical speed range.

I come to the table with different experience/application then yours, so what I say may not apply.

I find that gearing for "ideal" is not going to be the best in real world applications. What is best on a flat level road with no wind, will be geared too high on rolling terrain, with a cross wind, something much more likely to be the real world situation.

 I was either loaded to the max or empty, 3.90's were fine empty, but the truck gained .75 to  1 MPG loaded with 4.10's. A whole lot less shifting on slight hills also.

I can understand the desire to ditch the 6041, and I would agree, you are now almost double it's rating.

Personally, I find the Eaton/RR 15 a useless transmission. The steps are too much and the spread is better covered by a 13, the "15" is a close ratio 12 in reality.

ideally (which is not going to happen) I would have tried to find a Eaton 2 spd for the cut-off, that way you have the low speed bottom end when needed and the high speed ration needed.

If your going to make a change, map out your needs (low speed at idle through max desired speed) and then look at what is needed to achieve that.

 

Edited February 2 by Geoff Weeks

[Joseph Cummings]

The thing is the tip turbo needs cold air, not hot under hood air.

If the single disk held up behind your Maxidyne pulling what you are pulling, It'd probably be fine behind that Thermodyne, Unless someone put the fuel to it so it'd pull down low so they could use the TRL107 five speed. Then it may or may not be a problem.

I can tell you I've had Maxidynes opened up all the way with the APE or PLM pumps pumping as much as their little 11 millimeter plungers could pump, and never had a problem with the dual disk TRL107 based transmissions breaking. Pyrometer readings a little hot was more of a problem than drivetrain. That and the roller cam followers in the PLM pumps not holding up to all the stress. At least the early PLM

Edited February 2 by Joseph Cummings

[Mark T]

1 hour ago, Joseph Cummings said:

The thing is the tip turbo needs cold air, not hot under hood air.

If the single disk held up behind your Maxidyne pulling what you are pulling, It'd probably be fine behind that Thermodyne, Unless someone put the fuel to it so it'd pull down low so they could use the TRL107 five speed. Then it may or may not be a problem.

I can tell you I've had Maxidynes opened up all the way with the APE or PLM pumps pumping as much as their little 11 millimeter plungers could pump, and never had a problem with the dual disk TRL107 based transmissions breaking. Pyrometer readings a little hot was more of a problem than drivetrain. That and the roller cam followers in the PLM pumps not holding up to all the stress. At least the early PLM

Still easy to get stuff now to get fresh air to the tip fan without the Mack air cleaner.  Duct it from somewhere that was never thought about years ago without spending days making stuff.   

[Mark T]

2 hours ago, Geoff Weeks said:

Short shafts, the higher the critical speed. I was surprised that my stone stock driveline in my K put it well into critical speed range.

I come to the table with different experience/application then yours, so what I say may not apply.

I find that gearing for "ideal" is not going to be the best in real world applications. What is best on a flat level road with no wind, will be geared too high on rolling terrain, with a cross wind, something much more likely to be the real world situation.

 I was either loaded to the max or empty, 3.90's were fine empty, but the truck gained .75 to  1 MPG loaded with 4.10's. A whole lot less shifting on slight hills also.

I can understand the desire to ditch the 6041, and I would agree, you are now almost double it's rating.

Personally, I find the Eaton/RR 15 a useless transmission. The steps are too much and the spread is better covered by a 13, the "15" is a close ratio 12 in reality.

ideally (which is not going to happen) I would have tried to find a Eaton 2 spd for the cut-off, that way you have the low speed bottom end when needed and the high speed ration needed.

If your going to make a change, map out your needs (low speed at idle through max desired speed) and then look at what is needed to achieve that.

 

300  4.17s and a 15 over ???   they work. Lug'n mid 70 some thousand pounds.... they work.  15 has more overgear than an old RTO 13  and in direct with 4.10s still would go in the low 60s.

[Joseph Cummings]

1 minute ago, Mark T said:

Still easy to get stuff now to get fresh air to the tip fan without the Mack air cleaner.  Duct it from somewhere that was never thought about years ago without spending days making stuff.   

Oh yeah no problem with that, I just see lots of these conversions where they just put an aftermarket filter on the tip turbo and ignore the ducting

[Geoff Weeks]

I have both 13's and 15 over, I wouldn't have a 15 if I could avoid it. Lots of seat time with both, so I think I can speak from the point of experience

[Mark T]

4 minutes ago, Joseph Cummings said:

Oh yeah no problem with that, I just see lots of these conversions where they just put an aftermarket filter on the tip turbo and ignore the ducting

No doubt.  I think it's cool seeing some of these upgrades and referbs guys are doing now. Lots of them have been done in the past, but now things that are available that didn't exist years back ??? new twist on things.  I think it's interesting.

[Joseph Cummings]

4 minutes ago, Mark T said:

300  4.17s and a 15 over ???   they work. Lug'n mid 70 some thousand pounds.... they work.  15 has more overgear than an old RTO 13  and in direct with 4.10s still would go in the low 60s.

My R model with the trxl107 and 464 rears is a 70ish MPH truck

 

[Mark T]

Just now, Joseph Cummings said:

My R model with the trxl107 and 464 rears is a 70ish MPH truck

 

Lots of overgear in that transmission

[Geoff Weeks]

An Eaton 15 has 12 usable ratios, and those "extra" two over a 10 speed are lower than the lowest ratio's in a 10

All the other available ratios in "deep reduction" are mirrored in the low range of the trans.

A 13 has 13 useable and that is if you don't count "funny gear" (low in high range), with better steps between gears.

[Joseph Cummings]

5 minutes ago, Mark T said:

Lots of overgear in that transmission

You are thinking of that other one the TRXL1070 or 71, something like that. Mine is dirrect, 11r24.5, turning about 2400 rpm no load (I Think). 2400 is usually where I set high idle

[Mark T]

1 minute ago, Geoff Weeks said:

An Eaton 15 has 12 usable ratios, and those "extra" two over a 10 speed are lower than the lowest ratio's in a 10

All the other available ratios in "deep reduction" are mirrored in the low range of the trans.

A 13 has 13 useable and that is if you don't count "funny gear" (low in high range), with better steps between gears.

A 15 over is a highway transmission. Couple lower than a ten, and at the time a realistic overgear to make in a lever shift. If you were geared between 3.5 and 4.3 usually 1 2 3 and four in deep reduction, you could go to 4th in regular low range.   A direct 15 was quite a bit lower than an RTO 13 and made sense if you had a faster geared truck back then.  

[Joseph Cummings]

3 minutes ago, Mark T said:

A 15 over is a highway transmission. Couple lower than a ten, and at the time a realistic overgear to make in a lever shift. If you were geared between 3.5 and 4.3 usually 1 2 3 and four in deep reduction, you could go to 4th in regular low range.   A direct 15 was quite a bit lower than an RTO 13 and made sense if you had a faster geared truck back then.  

Trying to remember what I had in the diamond reo with the cummins. It was the 900 fp rated 15 speed with the deep reduction on the dash. Normally you drove it like a 10 speed