M925A2 transmission overheating

[simp5782]

I'm following this out of curiosity. I was under the impression that the MT654 was pretty reliable for the 5-ton. Having not done research on that bit, is reliability actually an issue?

The 654s are a typical medium class transmission for their day. They are junk by today's standards. They also don't last long when worked hard.

 

[Weldman]

The 654s are a typical medium class transmission for their day. They are junk by today's standards. They also don't last long when worked hard.

What do you suggest a replacement for them then that would be of standards that could bolt up?

 

[simp5782]

What do you suggest a replacement for them then that would be of standards that could bolt up?

There is no direct replacement that is better.

Upgraded automatic would be a WTEC 2 MD3060. These are found behind 8.3s that come in the A2s. They are found in M1117 ASVs in the military in that combo.

You could put It behind an NHC250 if needed.

A manual with a 10 or 13spd like @Crf450x is a cheaper route. Especially if your MT654 hasn't gone out. Sell it and it'll cover the cost of a 10spd .

Only other option is to make different cab and engine mounts and swap to an SAE 1 bellhousing and use an HT740, HT754 which non electrical transmission. Or you can do a CAT7155 16spd. Which I have already done.

 

[Weldman]

There is no direct replacement that is better.

Upgraded automatic would be a WTEC 2 MD3060. These are found behind 8.3s that come in the A2s. They are found in M1117 ASVs in the military in that combo.

You could put It behind an NHC250 if needed.

A manual with a 10 or 13spd like @Crf450x is a cheaper route. Especially if your MT654 hasn't gone out. Sell it and it'll cover the cost of a 10spd .

Only other option is to make different cab and engine mounts and swap to an SAE 1 bellhousing and use an HT740, HT754 which non electrical transmission. Or you can do a CAT7155 16spd. Which I have already done.

So you are saying my A2 has a WTEC 2 MD3060? Thought it was the MT654.

 

[simp5782]

So you are saying my A2 has a WTEC 2 MD3060? Thought it was the MT654.

I was referring that the MD3060 comes behind the 8.3s. Those motors found in the A2s. So it would be easier to find one to match that as they didn't put them behind NHC250s in any application.

 

[Weldman]

I was referring that the MD3060 comes behind the 8.3s. Those motors found in the A2s. So it would be easier to find one to match that as they didn't put them behind NHC250s in any application.

It's what I have is the 8.3 in M923A2 BMY, also have a spare 10 speed laying here rebuilt and never used.

 

[simp5782]

It's what I have is the 8.3 in M923A2 BMY, also have a spare 10 speed laying here rebuilt and never used.

Might be a little harder to do a manual on an A2 truck cause the transmission sits about 15inches further forward than on an A1 Truck.

You can use the WABCO air assisted clutch slave to make the clutch linkage alot easier. Since it's just hydraulic with air assist.

The shifter. I dunno @74M35A2 was supposed to do all this years ago on his A2 but he wimped out. along with his isx swap

 

[Weldman]

Might be a little harder to do a manual on an A2 truck cause the transmission sits about 15inches further forward than on an A1 Truck.

You can use the WABCO air assisted clutch slave to make the clutch linkage alot easier. Since it's just hydraulic with air assist.

The shifter. I dunno @74M35A2 was supposed to do all this years ago on his A2 but he wimped out. along with his isx swap

Sounds like extend the drive shaft a bit, realign the pinion angle and get a EZ pedal clutch . I never push the clutch in till I need to get the rig to move, other than it's floating up and down the gears. Of all my vehicles it's the only one I own with a automatic transmission.

 

[simp5782]

Sounds like extend the drive shaft a bit, realign the pinion angle and get a EZ pedal clutch . I never push the clutch in till I need to get the rig to move, other than it's floating up and down the gears. Of all my vehicles it's the only one I own with a automatic transmission.

The MT654 is the same length as most 10 speeds etc.

You would have to move the whole engine and transmission backwards to get direct shifter thru the floor.

Just have to rig up some linkages like the old cab overs had.

Transfer cases in the truck are offset to the passengers side so you don't have to reangle anything. The NHC250 the whole engine sits off center to clear the front pumpkin.

The hydraulic clutch is just so you can mount it anywhere you want and simply use a hose over having to put pivots in the frame, bend linkages etc.

I put a 13spd RTOO in a 920. The hydraulic pedal would have been so much easier.

You won't always float gears especially loaded on any hills. The 8.3 doesn't have enough guts to pull so the speed will drop so fast you won't be able to grab a gear without using the clutch. I learner this on the NHC250 at around 330hp using the CAT 7155 it would have to drop a gear every second to 3 seconds to catch up.

It was alot of work.

Simp's Cat 7155 Swap into a M923A1

Ok, so most people complain about how gutless the NHC250 is even with a turbo. Even with 5 speed or Allison they still just have that gap between 3-4 and 4-5 and then there is the top speed in question based on what tires you have. Bigger tires may help you go faster but you do loose that low...

www.steelsoldiers.com

 

[Weldman]

The MT654 is the same length as most 10 speeds etc.

You would have to move the whole engine and transmission backwards to get direct shifter thru the floor.

Just have to rig up some linkages like the old cab overs had.

Transfer cases in the truck are offset to the passengers side so you don't have to reangle anything. The NHC250 the whole engine sits off center to clear the front pumpkin.

The hydraulic clutch is just so you can mount it anywhere you want and simply use a hose over having to put pivots in the frame, bend linkages etc.

I put a 13spd RTOO in a 920. The hydraulic pedal would have been so much easier.

You won't always float gears especially loaded on any hills. The 8.3 doesn't have enough guts to pull so the speed will drop so fast you won't be able to grab a gear without using the clutch. I learner this on the NHC250 at around 330hp using the CAT 7155 it would have to drop a gear every second to 3 seconds to catch up.

Sounds like my DT466 except I have a FS6106A behind it then again I could split the axle on that one. Sounds like it's better to just grab a spare transmission before this one ever goes out or learn to rebuild it, not worth my time to go that deep into it with availability of parts or spare transmissions to grab before supplies dry up.

 

[simp5782]

Sounds like my DT466 except I have a FS6106A behind it then again I could split the axle on that one. Sounds like it's better to just grab a spare transmission before this one ever goes out or learn to rebuild it, not worth my time to go that deep into it with availability of parts or spare transmissions to grab before supplies dry up.

Just remember the MT654 In an A2 truck is different from an A1 truck. Different torque converter ratio and front pump is different

 

[jonesal]

Awesome, thanks! You saved me a bunch of time opening a few hundred disjointed pdf files I have saved. Hopefully this is it!

What ever happened with this? Did you ever figure it out? Thanks.

 

[purple_duckk]

What ever happened with this? Did you ever figure it out? Thanks.

Not yet. With the help of another guy near me that knows the transmissions pretty well we were able to troubleshoot it being a mechanical issue likely a stuck valve in the valve body. I'm waiting to get into a heavy diesel guy near me because messing with the valve body is a bit above my pay grade.

 

[jonesal]

Thanks for the update, please report back. Good luck! I hope it's not too $$.