M916-M920 Tech & Tips

[155mm]

Guess I could just go for the 920, loose the tag and 3k lbs.

... though with 14 total tires, you should be able to find a spare among one of them. .

Thats why I havent even considered changing my truck/trailers over to super singles, I have a greater sense of security with my spare already mounted next to the one that just gave birth to little alligators all over the highway.

 

[JH1]

I'd like to see the thread (or it's own forum, maybe?) include the M915, which I have. I can help anyone with converting the 915 to all 12v. Mine works great. I can even make 24v for the mil lighting plug if I add an inexpensive module. Basically, you just replace the 12/24V alternator and the starter with 12v units, change one relay and the fuel cutoff solenoid to 12v, and parallel 3 group 31 12V batteries.
Jim

 

[gpp111]

What is the correct transmission fluid to use in an M920?

 

[goodguyzy]

I would read TM lo 0-2320-273-12 if you have the cat 7155 tranny.

 

[M920]

What is the correct transmission fluid to use in an M920?

I talked to Caterpillar and they told me to use 15W 40 weight synthetic engine oil!
So in my M920 I used the synthetic 15W 40 Heavy Duty Diesel and Marine motor oil made by AMSOIL.

Soni

 

[gpp111]

Ok thanks. I am not sure what is in the truck now, should I drain and refill the trans fluid or just top it off.
thanks

 

[M920]

Topping it off with a non synthetic 15W 40 motor oil would probably be safe, if you don't want to change all the fluid.

 

[gpp111]

Here is what I found for the correct oil to use in the Cat 7155 trans.

 

[gpp111]

Here is a source for Cat 7155 transmission operator and user manuals

http://www.jensales.com/Caterpillar...nt-Service-Manual-CT-S-7155-TRAN_p_83552.html

http://www.jensales.com/Caterpillar...p-Operator-Manual-CT-O-7155-TRAN_p_68518.html

 

[NDT]

My M915 would not build air past 60 PSI. Other symptoms were the Bendix AD-2 air dryer was weeping air (not much) out the bottom sneeze hole. An AD-2 purge valve rebuild kit (available at any heavy duty parts house, around $10) fixed both the weeping and the low air build. Apparently, the air that unloads the compressor was escaping though the AD-2 purge valve, causing the compressor to remain partially unloaded. The AD-2 is used on all the M915-916-917-919-920 trucks.

 

[Csm Davis]

Have a 916 that we drove and then parked now it is stuck in reverse no matter what gear you put it in

 

[M920]

Have a 916 that we drove and then parked now it is stuck in reverse no matter what gear you put it in

Mine did that whenever it was cold. I would let the truck warm up for a while and it would miraculously start working again. Try to let it warm up for a while with the air charge button pushed in on the side of the shift selector box.

Soni

 

[Csm Davis]

Thanks Soni it did just get cool down here, we will try that.

 

[NDT]

The M915 M916 M920 all have an air check valve on the inlet to the second tank which can leak air. It is p/n 1040 or 4820-01-076-9493. This part appears to be obsolete. A suitable replacement is the Velvac 320014. You must use a 3/8 street elbow to make this fit.

 

[goodguyzy]

smoking

I did a nine hour round trip and was having problems with "heavy smoke" I first noticed the trailer had a layer of an oily substance on the stack side and also the back and top of cab near stack. I kept on eye on the oil level as I thought I was losing the turbo. The oil level never changed. When running at speed you don't notice any smoke but at idle and first throttle you do. I was running at 2000-2200 rpm for the trip. Ideas? BTW this is on the M916

 

[NDT]

Everything tip-top shape in the air cleaner dept? Maybe remove the element temporarily and see if that helps. The inside of the stack should be sooty but not oily. Oily means trouble, start diagnosis with the turbocharger.

 

[goodguyzy]

I will start there, I don't drive this truck much. Maybe a squirrel was busy since the last time.

 

[goodguyzy]

Air cleaners are clean and checked intake pipe and no squirrels.

 

[Csm Davis]

Mine did that whenever it was cold. I would let the truck warm up for a while and it would miraculously start working again. Try to let it warm up for a while with the air charge button pushed in on the side of the shift selector box.

Soni

Okay so we had a warm day a bam it works, so what's the fix? We were going to send this truck north and this will be a pain up there.

 

[Tinydragon2001]

We are looking to pick up a m920. I am just curious about how to properly shift the cat 16 spd trans. If someone could please post a video on youtube on how to shift these trans, I'm sure I am not the only one that would appreciate it. I know you guys are busy, but any help would be greatly appreciated.