M925a2 Power Surge

[Another Ahab]

Still learning. The ISL comes with steel dome topped 2 piece pistons. There goes EGT concerns. Was wondering how they squeeze 400-450hp from a stroked 8.3L, reliably.

I really need to figure out how to retain and pull my transmission modulator cable when using an electronic accelerator pedal.

You're kidding right, is that a real thing?!

 

[Jbulach]

...I really need to figure out how to retain and pull my transmission modulator cable when using an electronic accelerator pedal.

I wonder how the trany would act if you ran the cable off the pedal, instead of the pump?

 

[74M35A2]

Should not care, and that is where I am headed with it. Route the cable inside, and connect it to the pedal arm.

 

[simp5782]

Should not care, and that is where I am headed with it. Route the cable inside, and connect it to the pedal arm.

That 654 is gonna hold up to about 40miles of abuse and the 4th gear band is gonna break

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[74M35A2]

@ 1200ft-lb's, we'll find out. Possible MT654CR for sale, needs work. No strings attached.

 

[74M35A2]

Looks like the first and second generation Dodge Ram pickups with the Cummins engines used exactly what I need to resolve the trans modulator cable and accel position sensor issue I would run into. They used a mechanical pedal, but it pulled on a bellcrank under the hood which had an accel position sensor on it, along with a tab to mount and pull the trans TV cable. I can use this, and then just switch out my cab pedal from a linkage to cable pull style, and we should be good to go. Perfect!

Engine pickup is about a month out from now.

 

[silverstate55]

Let me know how much the [915] 916 transfer case costs you!

The M916-series transfer cases are only single-speed; no high-low.

 

[grendel]

With a 13:1 first gear, who needs low range in the t-case. Then there's at least 4 more gears before he gets to 5:1...

 

[Csm Davis]

With a 13:1 first gear, who needs low range in the t-case. Then there's at least 4 more gears before he gets to 5:1...

Ask Simpson about that!

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[74M35A2]

It seems like 13 speed transmissions are either double low, or double over (drive)? Is there any that is just one of each? Or maybe that is what you do with the double-over one?

Simp says the 654 tranny is rated to 950ft-lbs. The ISL engine is torque limited to 1200ft-lb even, per request of Allison trans limits. I'm hoping 950 and 1200 are close enough, considering it will always be an empty truck. If I do bust it, which would be a shame because it is a butter smooth shifting transmission with zero leaks, another auto is not going in there. We are going to be rowing gears one way or another.

Tranny choices so far are the stock Allsion MT654CR 5 speed auto, the stock RV Allison 3000 MH 6 speed auto from the motorhome the ISL was in, a 6 speed manual Eaton single countershaft from an 8.3L powered Freightliner with an 8.3L, or the 13 speed grendel threw over the fence, supposedly a double low (LL) type deal.

The more I learn, the more I discover I don't know, about anything...

 

[red]

Most of the Eaton Fuller 13 speeds have a 12:1 first gear, which is deeper than the 'ultra deep' 10:1 reverse gear that your Allison MT654 has.

For reference the 5 speed Spicer 6453 in the m809 series is a roughly 6:1 first gear. Video of my m816 going up a hill at 600-800rpm, 1st gear low so 12:1 after the tcase.

https://www.youtube.com/watch?v=nl1kEIg3cno&feature=youtu.be


There's some variation in each series but this covers most models in the 13 speeds:
If you plan to stay with your stock tcase and no improvement in highway RPM: RT or RTF series. 1:1
Stock tcase and better highway RPM: RTO, RTOF. .87:1
Changing tcase to one with a 1:1 high range and maintain your current highway RPM: RTLO, RTLOF. .73:1
Changing tcase to a 1:1 high range and lower highway RPM: RTOO, RTOOF. .62:1

 

[Rmtaunton]

I have found a couple of super 10's near me and really thinking about it as i hate the auto , my first gear is worst than other 939's for some reason


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[74M35A2]

M939 stock t-case is not 1:1 in high?

Super-10 trans single or dual counter-shaft? I think anything over 6 gears is double?

 

[Rmtaunton]

M925a2 Power Surge !!!

It's duel


And what is the gearing on that 6 speed ?

 

[simp5782]

M939 stock t-case is not 1:1 in high?

Super-10 trans single or dual counter-shaft? I think anything over 6 gears is double?

.83

 

[simp5782]

I have found a couple of super 10's near me and really thinking about it as i hate the auto , my first gear is worst than other 939's for some reason


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Then fix your modulator cable rook.

Don't feel bad though. I was in Kentucky a few weeks back and I went up a hill towing my trailer with an SEE on it and my truck would not pull up it in 1st gear high. Nor would it hold itself on the hill with the brakes hardly.

My new 1st gear will be around 14.32 or 17.32 : 1

 

[red]

.83

T1138 is .73:1 in high range. The Allison auto is 1:1 in the m939 series giving a final top gear of .73:1.

Spicer 6453 in the m809 series is .78:1 5th gear, 1:1 high range tcase giving a final top gear of .78:1.

Not including axle gears.

Thats why with the same size tires and same engine the m939 series is faster.

http://www.steelsoldiers.com/showthread.php?59654-M818-Transfer-Case-Upgrade-T-138-to-T-1138

 

[Csm Davis]

T1138 is .73:1 in high range. The Allison auto is 1:1 in the m939 series giving a final top gear of .73:1.

Spicer 6453 in the m809 series is .78:1 5th gear, 1:1 high range tcase giving a final top gear of .78:1.

Not including axle gears.

Thats why with the same size tires and same engine the m939 series is faster.

http://www.steelsoldiers.com/showthread.php?59654-M818-Transfer-Case-Upgrade-T-138-to-T-1138

So a Spicer 6453 in front of a T1138 would give you a overdrive ratio of 0.5694? Right?

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[red]

So a Spicer 6453 in front of a T1138 would give you a overdrive ratio of 0.5694? Right?

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correct. That's exactly what was done to a m818 in the thread link. I had been planning to do the same thing to my m816 but the tcase pto is different on the T1138 than my T138 and those PTO outputs are pricey.

 

[Csm Davis]

There's some variation in each series but this covers most models in the 13 speeds:
If you plan to stay with your stock tcase and no improvement in highway RPM: RT or RTF series. 1:1
Stock tcase and better highway RPM: RTO, RTOF. .87:1
Changing tcase to one with a 1:1 high range and maintain your current highway RPM: RTLO, RTLOF. .73:1
Changing tcase to a 1:1 high range and lower highway RPM: RTOO, RTOOF. .62:1

Okay love the information but need a guide to understand what I am seeing, what does RPMTLOF stand for? Each letter please.

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