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JLTV, Humvee replacement


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#1 Gunguy

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Posted 07 September 2007 - 0915 AM

I just read that the MRAP program sucking up money has delayed JLTV for at least two years. This is going to cost a bunch of money as the Humvees will all be rebuilt and reset instead of replaced. Then they will be replaced shortly after that. Also, as we all mentioned before, MRAP will come on strong just as we leave Iraq in a few or three years. So, costs overall go up. But the good point is that JLTV is still going to be a huge improvement over the hummvee. I still am amazed they are planning on having it generate 30 KW of electric power! I hope it doesn't get pushed off in future even longer.
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#2 Guest_pfcem_*

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Posted 07 September 2007 - 1118 AM

http://www.nationald...tgeneration.htm
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#3 medicjim86

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Posted 07 September 2007 - 1146 AM

I still am amazed they are planning on having it generate 30 KW of electric power! I hope it doesn't get pushed off in future even longer.


Our more recently delivered fire apparatus come equipped with 25 kW PTO driven generators in line with the drive train...they are "NICE". It's old tech at this point...widely deployed

Edited by medicjim86, 07 September 2007 - 1147 AM.

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#4 rmgill

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Posted 07 September 2007 - 1500 PM

What Jim says is true. A PTO drive to run a winch isn't any different than running a generator set, a pump or any number of other devices. Pretty simple stuff. You just have to figure on the engine running when you need the power. Its really no different than a really stonking big secondary alternator thats belt driven off the front pulley.
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#5 Gunguy

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Posted 08 September 2007 - 0951 AM

http://www.nationald...tgeneration.htm



Great Link! Lots of good info in the write up.
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#6 Kensuke

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Posted 08 September 2007 - 1904 PM

It's called "Throw a bigger alternator on the thing". Ford does this will all their special duty vehicles.

A friend of mine who was a sheriff deputy says that they always keep the engines running when they have all those pretty flashing lights blinking.

- John
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#7 Exel

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Posted 09 September 2007 - 0616 AM

Is there something actually wrong with the Humvees as long as they are used in their intended role as utility vehicles and not as front line fighting vehicles?
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#8 Guest_pfcem_*

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Posted 09 September 2007 - 1900 PM

Is there something actually wrong with the Humvees as long as they are used in their intended role as utility vehicles and not as front line fighting vehicles?

Aside from a outdated powertrain, not really.

What is sad is all the time & money being spent developing a MRAP replacement for the HMMWV that is going to be too heavy & too expensive to be a realistic replacement for the HMMWV for MOST of what the HMMWV was intended to do. Not to say that such a vehicle is not useful or needed but as a supplement to rather tha a replacement for the HMMWV. Even more so given that we already have/had a vehicle designed & procured (though in reduced numbers & almost cancelled altogether) which have proven VERY popular & capable in Iraq with the M1117 Guardian Armored Security Vehicle (ASV).
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#9 Kensuke

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Posted 10 September 2007 - 0225 AM

Aside from a outdated powertrain, not really.


AFAIK, the M1114's powertrain has gotten good marks. The problems with the M998 centered primarily around the 3-speed transmission that would randomly commit suicide if exposed to too much stress (overloading the vehicle with armor or gear or both), and the overall sluggishness of the engine. AM General fixed this by adding a turbocharger, and mating it to a stronger 4-speed tranny.

Awhile ago, one of our posters here on TN came back from Iraq and wrote in details as to what models suck and what ones are good.

- John
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#10 Corinthian

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Posted 10 September 2007 - 0650 AM

Awhile ago, one of our posters here on TN came back from Iraq and wrote in details as to what models suck and what ones are good.

- John



IIRC, the gist of that discussion was that the models with the armour were ok, while those models built without armour but were given ASK didn't perform all too well because the chassis/powertrain/whatever wasn't able to deal with all that extra weight. Lastly, the original ones with no armour were the worst.
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#11 Guest_pfcem_*

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Posted 10 September 2007 - 1150 AM

AFAIK, the M1114's powertrain has gotten good marks. The problems with the M998 centered primarily around the 3-speed transmission that would randomly commit suicide if exposed to too much stress (overloading the vehicle with armor or gear or both), and the overall sluggishness of the engine. AM General fixed this by adding a turbocharger, and mating it to a stronger 4-speed tranny.

Awhile ago, one of our posters here on TN came back from Iraq and wrote in details as to what models suck and what ones are good.

- John

Yeah the turbo was a big help to the old 6.5 GM diesel but...

If you can find them, test drive a 2000-2004 Hummer H1 (nearest equivalent to the M1114 powertrain) & then test drive a 2006 Hummer H1. ;) And don't forget that the M1114 is MUCH heavier than the Hummer H1.
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#12 Kensuke

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Posted 10 September 2007 - 1213 PM

Yeah the turbo was a big help to the old 6.5 GM diesel but...

If you can find them, test drive a 2000-2004 Hummer H1 (nearest equivalent to the M1114 powertrain) & then test drive a 2006 Hummer H1. ;) And don't forget that the M1114 is MUCH heavier than the Hummer H1.


The GM 6.2 and 6.5 were designed foremost with reliability in mind.

The new Duramax is a sexy engine, but it remains to be seen if it's militarily acceptable. For instance, I'm not sure if anybody has done a serious study as to the pros and cons of aluminum heads (or blocks for that matter) in military vehicles. Plus it has twice as many valves which means there is more that can go wrong. Sometimes the lower-tech is the better tech. We're not talking about a sports car here.

The 6.5L Turbo can and has been modified to give up to 300 hp.

- John

Edited by Kensuke, 10 September 2007 - 1216 PM.

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#13 rmgill

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Posted 10 September 2007 - 1214 PM

There were also odd problems with the drivetrain. One thing termed I've seen in the MV community is the Vampire transmission issue. The transmission had a coolant line (oil) that ran through the Transfer box. It would develop a stress fracture in the coolant line and one gearbox would start to loose oil and after a certain point of running (it wasn't leaking that you could easily see) it would fail. The transmission fluid would leak into the other reservoir and you'd never no that you were missing the necessary fluid. Overloading probably made this problem MORE manifest and the self destruction that much faster.
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#14 Guest_pfcem_*

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Posted 10 September 2007 - 1302 PM

The GM 6.2 and 6.5 were designed foremost with reliability in mind.

The new Duramax is a sexy engine, but it remains to be seen if it's militarily acceptable. For instance, I'm not sure if anybody has done a serious study as to the pros and cons of aluminum heads (or blocks for that matter) in military vehicles. Plus it has twice as many valves which means there is more that can go wrong. Sometimes the lower-tech is the better tech. We're not talking about a sports car here.

The 6.5L Turbo can and has been modified to give up to 300 hp.

- John

Its not just the power difference...

smootheness
quitness
emissions
fuel effeciency
et cetera

...and a modern commercial diesel (Duramax or otherwise) will more reliably produce whatever power (hp &/or torque) level you desire than the OLD 6.5L GM diesel.

Sure you can "hot rod" an OLD 6.5L GM diesel to 300 hp but modern stock diesels (of similar displacement) ALREADY (& under warantee) produce more than that.

And I am not saying that replacing the 6.5L GM diesel with a Duramax or other modern commercially available light-duty truck (& yes even 1 ton pick-ups are light-duty) diesel is the answer, just pointing out that the OLD 6.5L GM diesel is outdated (& not just in terms of hp &/or torque) & in most HMMWV overtaxed.
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#15 EchoFiveMike

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Posted 10 September 2007 - 2309 PM

The 6.2 and 6.5 diesels were/are lumps. Their only advantage is for fording you don't have to deal with the hot turbo housing and possible blown turbo issues. I run a 06 Duramax in a 5500 Chevy and it's an impressive motor. Aluminium heads, blocks and other parts are fine for .mil use, better than cast iron since they weigh less. Only issue is slightly less thermal efficiency. The modern motors are great WRT reliability once you get the emissions crap off them and bulletproof the electronics.

Does anyone know if the GM TH series of transmissions has the lubricant pumps run off the input or output shaft? A huge problem with truck trannies is that the lubricant pumps are powered off the input side, thus you need to drop the driveline when towing them or else they get eaten up. If it's the same condition with the POS TH tranny, then the breakdowns and tow ins compound the problems. S/F....Ken M
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#16 Paul in Qatar

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Posted 13 September 2007 - 0654 AM

They are going to start evaluating bids next year! Wonderful! Then we can justify the procurement strategy in the five-year development plan! We will be printing our preliminary proposals for pre-planned product improvements as early as 2012.

You got to love the Combat Developments community. Nothing will hurry them along.
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#17 Adam Peter

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Posted 02 March 2019 - 1927 PM

The Pentagon Just Slammed This Contractor's Flagship Vehicle

The initial reports are discouraging, but the Humvee replacement can still be a winner.

 

 

The first Oshkosh-made Joint Light Tactical Vehicles (JLTVs) were fielded at Fort Stewart in Georgia in mid-January, a major milestone for one of the Army's priority replacement programs. But according to an annual report prepared by the Pentagon's Director of Operational Test and Evaluation, those vehicles suffer from a range of issues in areas including "reliability, maintainability, training, manuals, crew situational awareness, and safety."

 

It is a very slow birth...

 

 

The vehicle will likely require more maintenance than the Humvee, the audit warns, with a greater reliance on contractors to perform that maintenance due to its "poor manuals, and the challenges with troubleshooting the vehicle."

 

M1 in Iraqi service, anyone?

 

 

The close-combat version is "not operationally effective for use in combat and tactical missions" at this time, the audit warns, because the missile reload process "is slow and difficult for crews," and the JLTV provides poor visibility for crews.

The vehicle is also at a greater risk of being detected on the battlefield because of its larger size and greater noise signature, the report found.

 

Original source (Hun), their only English source referenced

 

26795773_fd72c71794ed205a9c208319178a46c


Edited by Adam Peter, 02 March 2019 - 1927 PM.

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#18 Colin

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Posted 02 March 2019 - 2338 PM

I had a PTO winch on the Series Landrover, it was a beast, speed control by a hand throttle, you could pull all day without the overheating problems you get with electric and most hydraulic winches. (not to mention bubble, Hydraulic systems should have large reservoirs to allow the oil to cool and bubbles to move out of suspension. needless to say, very very vehicle winches come with large reservoirs.)   


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