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6.5 W/ Over Drive vs 6.2 W/ 3 Speed
- Thread starter seca954
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The unit with the overdrive is a 6.5L Turbo Diesel and the reg 6.5 and 6.2 with the 3 speed transmissions are normally aspirated. The Turbo diesel has more horse power and torque and along with the OD transmission can better handle the armored HMMWV and has a higher MPH on the highway. My reg 6.5 gets about 17MPH on the highway doing 60-62MPH.
Mark
Mark
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M1123's are 6.5NA with 4 Spd trans....they are not turbos.
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they still haul butt compared to the detuned 6.5 with TH400.
What is the difference between the GEP 6.5 that shows up in some M998s and the 6.5 in the M1123s aside from the serpentine belt?
Wire Fox
Well-known member
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Significant reliability improvements across the board with the GEP. The most notable thing I can think of that they have made multiple changes to prevent the block from cracking and resulting in engine failure. If I had a GM 6.5 and it failed, I wouldn't even look at another GM unless it was free or darn close to it. However, I wouldn't replace an already strong-running GM 6.5 until it actually irreparably failed.
*EDIT* Just thought it was worth pointing out that these differences are very well-discussed on here. Try searching 6.5 GEP in the Google search box at the top-right of the forum. You'll find lots of information about what's in the 6.5 GEP and what's better than the GM 6.5 and 6.2.
*EDIT* Just thought it was worth pointing out that these differences are very well-discussed on here. Try searching 6.5 GEP in the Google search box at the top-right of the forum. You'll find lots of information about what's in the 6.5 GEP and what's better than the GM 6.5 and 6.2.
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Check this link out. http://www.steelsoldiers.com/showthread.php?162090-Good-Article-on-the-Optimizer
Very well aware of the GM vs GEP difference. I was asking specifically the difference between the GEP 6.5 that are used as replacements in the m998 and the GEP 6.5 that is used in the M1123.
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The GP M1123's don't have GEP motors....a GEP Motor is a GEP motor, but....the term is called "detuned"
the v-belt trucks got "whatever 6.5 mfg,be it GM or GEP" a replacement motor that was equipped with v-belt pulleys, water pump etc, to be a drop in replacement for the discontinued 6.2.
The serpentine equipped GEP motor "there are 3 variations of serpentine pully setup based on serial number" is equipped to be installed into a truck with 4L80E.
Now I am confused because many of the GP ads for the M1123s are listed with a GEP 6.5L. Who makes the 6.5 in the M1123?
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From what I've seen, they are Melton rebuilds, GM motor. Does not mean they might not have a GEP motor, but unless I see the decal on the valve cover, all bets are off.
Seriously? Someone can be paying $20k and getting a problem waiting to happen GM rebuild?
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Really? People are paying 14k and more for 6.2 equipped trucks, the M1123 is not only 6.5NA but 4L80E equipped along with full 12k chassis and running gear. They are worth 20k without a motor. People want to whine about GM 6.5 but disregard there are millions of them in use worldwide. 99.9% of every hmmwv owner will never experience a motor failure on there truck, regardless of what motor they have.
waiting for your motor to implode is like sitting around waiting to die....you have no idea when your number is up.
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MaverickH1
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I always thought that having the GEP motor will depend on which year your truck is and obviously the maintenance history. I fully expect that my 2005 M1123 DOES have a GEP 6.5, I wouldn't expect a 1998 M1123 to have a GEP 6.5 unless it was replaced.
For what it's worth... mine has plates glued to the engine and transmission that say "RB 2009" as if both were rebuilt in 2009. Which is scary. Or maybe not. It might also mean that the engine is no longer a GEP. I tried to look once but didn't see any identifying marks.
The Hummer H1s started having GEP engines in 2000 and 2001, somewhere in that timeframe. I suspect HMMWVs were similar.
For what it's worth... mine has plates glued to the engine and transmission that say "RB 2009" as if both were rebuilt in 2009. Which is scary. Or maybe not. It might also mean that the engine is no longer a GEP. I tried to look once but didn't see any identifying marks.
The Hummer H1s started having GEP engines in 2000 and 2001, somewhere in that timeframe. I suspect HMMWVs were similar.
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All bets are off for any hmmwv having gone through reset...depot rebuilt motors should have rebuild tag from that base.
there is no hard and fast though, generally the easiest way to tell if you have a rebuilt motor is if the entire motor painted black. On non-rebuilt motors the intake manifold is still fresh aluminum and not painted black.
I have found every GP truck I have received so far "9" have had a motor change out, the 6.5 is the obvious one, but the 6.2's I've had installed are short injector 1990 and later motors installed in 1985-1989 trucks.
when I get a truck, I check the injector pump model and injector length to figure it out.
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Also, you have to be real careful on the model years, there have been plenty of m998's sold at GP that are data plated as 2004 and later and they are just a 6.2, 3 spd truck. Data plates are just like speedometers in the military, though not as bad. If the DP was missing or was removed and lost in reset, it gets a new DP with a new year.
I know for s fact that guys bought These trucks thinks they had all the new bells and whistles and they did not.
here is the worst part....at least here in calif, the reason I have not bought an m1123 year is the model year, here in the Bay Area, 1998 and above requires smog, so I want nothing to do with that.
I know for s fact that guys bought These trucks thinks they had all the new bells and whistles and they did not.
here is the worst part....at least here in calif, the reason I have not bought an m1123 year is the model year, here in the Bay Area, 1998 and above requires smog, so I want nothing to do with that.
Easy to see the date code on the back of the motor.
Right side below head on block.
GEP's date starts as numbers then letters, an " H " for 2001, or J, 2002, K, 2003, and so on.....L, M, N, P.....etc.
No code I, or O.
So...11 03 L is a : nov. 03 2004 cast date motor.
Right side below head on block.
GEP's date starts as numbers then letters, an " H " for 2001, or J, 2002, K, 2003, and so on.....L, M, N, P.....etc.
No code I, or O.
So...11 03 L is a : nov. 03 2004 cast date motor.
MaverickH1
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The odd thing about my truck is that it is a 2005 model year according to the data plate, but the rebuild date on the engine and tranny is 2009. The tires are from 2009 also.
So if they replaced the data plate in 2009 during the reset, I'm unsure why it would say a delivery date of 2005.
Edited to add - I will be going home in 2.5 hours and my first order of business will be to find out which engine it is.
So if they replaced the data plate in 2009 during the reset, I'm unsure why it would say a delivery date of 2005.
Edited to add - I will be going home in 2.5 hours and my first order of business will be to find out which engine it is.
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The original delivery date should always stay the same.....but some reset places put a new date on a new main data plate when they reset it which is wrong.
The new reset date is normally on a different data plate if they did it correct
The new reset date is normally on a different data plate if they did it correct