Allison AT1545 failures

[URSATDX]

What temperatures are you guys seeing on your 1545s?
Mine is still 15w40 and even after an hours drive with outside temps at 50
I'm only seeing 135 or so degrees on the gauge and verified with an infrared temp gun.
I can heat it up to 180 or so if I spend some time climbing hills or driving soft sand for a while.
If temps outside get over 90 degrees I usually see 180 or so.
My transfer case runs hotter than my trans (infrared).
Thanks

 

[sue]

What temperatures are you guys seeing on your 1545s?
Mine is still 15w40 and even after an hours drive with outside temps at 50
I'm only seeing 135 or so degrees on the gauge and verified with an infrared temp gun.
I can heat it up to 180 or so if I spend some time climbing hills or driving soft sand for a while.
If temps outside get over 90 degrees I usually see 180 or so.
My transfer case runs hotter than my trans (infrared).
Thanks

My trans gage is way off, but it’s consistent, about
75 degrees cooler than the gage. Verified with output line.
Switched to Dextron 3, no regrets, 19k and still driving biweekly. Pulled some 12k loads ( on a flatbed trailer) with it.
It’s a 1545 love it. And yes for the record our opinion
is that the military used 15-40 for reduced stores (supply) count. And could a new G.I add and mix the wrong type of fluid, trans for engine and vise versa and did they envision there trucks lasting for decades, no absolutely not.
Is 15-40 the best for your trans, no but will it work,
yes, good enough for 18-19 year old kids to drive.
In the hot a** Middle East it’s not uncommon for hmmwv engines to be changed monthly. Would synthetic oil help them last longer? But then again
another new fluid to stock.

 

[MSV Marine]

I have a M998 HMMWV and am new to the forum.

Do you have any recommendations for brand and type of transmission fluid you would use. The military manuals I have ask for DexronII. Would I be better suited with a Dexron III fluid.

Many thanks, Matt

 

[1967pont]

I made the change from 15W40 to NAPA part #75203 Dex III today. Since I am home from work, trying to keep myself busy. Took (2) 5 gallon buckets to complete doing the drain-refill-drive a little-shift thru the gears, 4 times total. I had changed the 15W40 and internal filter a couple years and only 60 miles ago, so I did not change the internal filter again. I did change the external filter with a NAPA 1268. After the second drain and refill, the trans noticeably shifted easier. I'll probably put a few more miles on it and do another drain and refill, may even do the internal filter change.

Not sure when others did the change to Dex III when exactly they started having issues, if it was during the drain-refill or shortly thereafter, but so far no issues.

 

[glcaines]

I made the change from 15W40 to NAPA part #75203 Dex III today. Since I am home from work, trying to keep myself busy. Took (2) 5 gallon buckets to complete doing the drain-refill-drive a little-shift thru the gears, 4 times total. I had changed the 15W40 and internal filter a couple years and only 60 miles ago, so I did not change the internal filter again. I did change the external filter with a NAPA 1268. After the second drain and refill, the trans noticeably shifted easier. I'll probably put a few more miles on it and do another drain and refill, may even do the internal filter change.

Not sure when others did the change to Dex III when exactly they started having issues, if it was during the drain-refill or shortly thereafter, but so far no issues.

After my switch to Dexron III, I've had zero problems. Just the opposite. The transmission is much much happier and I've put thousands of miles on it since the switch.

 

[1967pont]

That's great to hear Gary, thank you.

Was wondering for those that did have failures doing the Dex III, when the issues showed up. Was it immediate or did it take some miles?

 

[Potluckslammy]

Is it appropriate to flush the trans the first time through with diesel fuel? This seems the correct place to ask, as nothing turned up in search. My concern is the efficient removal of the 15W40 without three or four flushes, and without wasting gallons and gallons of DexIII. My thought is to drain, fill with diesel, start engine and cycle through the gears, then drain and drop the pan...change filters, refill with DexIII, run up to NOT on the road, drain again, and refill. I can't imagine there would be any danger of contamination to the new fluid to a greater degree than with residual traces of 15W40. Thoughts? Is damage possible/likely to the internals with this short run cycle?

 

[glcaines]

You don't want to put diesel fuel in your transmission. Dexron III isn't that expensive if you buy a five-gallon pail of it. Go to NAPA and buy their Dexron III equivalent. It is made by Ashland Oil and is identical with Valvoline brand Dexron III.

 

[Balalala]

Ah!

Checked the oil in the 1545 transmission and fluid came shooting out! It wasn't overfilled before, after driving it, the fluid became pressurized

 

[SteelNinja]

vent tube plugged up?

 

[Balalala]

vent tube plugged up?

Yessir it was!

vent tube plugged up?

Yessir it was!