Acquired a M35A3

[lonegunman]

Thanks lonegunman. After putting a few more miles on it, the transmission as started shifting a bit more regular, but still shifts slightly over 2,500 RPM. Is this okay?

Even if it is okay, it bothers me to have to push the engine that high every time I want to accelerate. If it's not under a load, why would the manufacture have the shift points set so high? That said, no matter how I try to manipulate the acceleration, the shift points stay about the same.

I like the idea of reconfiguring the Allison to set the shift points lower. The Cat 3116 seems to have more than enough low end torque to handle a 1,500 RPM shift point when operating without load.

That would be similar to where my dodge diesel shifts. Sure seems like a lot less stress on the engine and trans.

2,500 rpm first gear shifts sounds better. As soon as I got my truck I swapped it to ATF and replaced both the internal and external filters, it smoothed out and ran about 20 degrees cooler. Mine seems to hold for a higher rpm even when accelerating slower as well.

The Cat has tons of torque at lower RPMs so you got me as to why they shift higher. One thing I also had verified was the tach, it took the Cat guy about three minutes to check it and it made me feel a lot better to see that the tach was right on the money.

I think a bit more driving will sort things out and give you an idea what needs checked.

 

[SHBENNETT]

Going to try some auto transmission fluid. Any recomendation on what type?

Also, anyone have any ideas on my steering woes?

 

[AceHigh]

3rd Question:
So how hard should the steering be if the air assist is working properly? Should it compare to normal power steering, or be quite a bit more difficult to steer? Mine is still fairly hard to steer even with the assist. Im thinkin this might have something to do with the CTIS low manifold pressure? When sitting still, it's just about all I can do to turn it from side to side with both hands. I'm 6'2", 200lbs. Also, the bump steer will take your thumbs off if you're not carefull. This said, I'm thinking I might have a problem with the steering assist. Any ideas or things to check first?

It has nothing to do with CTIS and should work almost like hydro power steering when the air pressure is up over 90 psi or so. Should hear air venting off when you let go of the wheel to return to center. If not remove a line on the cylinder and squirt some air tool oil in, also make sure the air valve to the system is on, located on the firewall.

 

[SHBENNETT]

Where is the valve on the firewall?

 

[runk]

If the valve is in the same place you are instructed to install it by the A2 retrofit kits, high on the driver's side of the firewall, in the engine compartment. It is just a cheesy little brass needle valve with a folded metal "T" handle, next thing in the line is a bigger aluminum block thing, which is the pressure closing valve (doesn't let air go to the steering until the system pressure builds up over ~ 70 PSI), air to the brakes is more important ! Then the line goes down to the inside of the frame rail near the driver's side front tire. Next is a crummy regulator, which was removed in the later kits, and some in the field (I installed mine, and it failed ~10 miles later, got to test the pressure closing valve !). Then through the frame rail to the drag link / control valve.

Steering should be pretty easy with it working, not quite finger tip, but certainly one handed, and it damps out the kick back big time.

I would check to make sure air is getting all the way to the drag link / control valve. If it is, try a little (couple of drops) air tool oil at the valve inlet line and cycle the steering. There is another current tread about a sticking (after long storage) valve.

 

[DeneMoore]

I will try that trick too.
I just bought an A3 with 3200 miles on it and 300 hrs. Everything works perfectly except that after about 4 hours into my trip the CTIS started reading [flat?]. The manifold would try to pressure up, make it to 5 or 6, then claim it is unable to pressurize the manifold. I measured the pressure on the tires, and they are all maintaining perfect pressure. When I stepped outside I noticed the manifold honking allot like a goose, so I just shut the CTIS off, as i didn't want any damage or strain done on the system.
A thousand miles later in my journey and the tires are maintaining pressure.
My steering is stiff too. I ran through the procedure in the manual, (closing the valve and cranking the wheel) but it didn't help. I'm also hoping it can be improved.

And congrats on your purchase. Have you checked the oil yet? My eyes had never seen clean motor oil in a diesel before.

 

[AceHigh]

My eyes had never seen clean motor oil in a diesel before.

It stays clean for at least 5 minutes after oil change! Then it instantly turns black.

 

[jimmcld]

I drove one belonging to a friend. I couldn't get it to shift out of first gear. However, I didn't want to get it over 2000 rpm. He got in and pushed it up to 2500 and it shifted flawlessly. I'm just not used to winding one out that tight. Also, his steering is a bear. I don't know about turning lock to lock with it sitting still. I think that puts an undue strain on any steering system. However, the air assist in our club deuce (A2) is a lot easier to turn. Thirdly, his CTIS will not even turn on. I believe the Army had trouble with it also. There is a big spot on the dash that has been ground off and a ground wire run to it to try to make a better ground. Personally, I believe there is a connection between the CTIS and the lack of power going to the air assist. I was told that the CTIS would not turn on if there was no air pressure going to it.

If you figure it out, let me know what you found. I think a lot of people would be interested.

 

[doghead]

Did you solve your issues?

 

[renovate7]

Same here. I've been on 3 trips now and don't think I'm getting any help from the power steering. I'm going to look into it this weekend... I'm REALLY enjoying the automatic transmission. It's shifting smoother and better each trip. Doesn't seem to run up to high in the gears. Very noticeable power and acceceration when you go into third and fourth. My optimum speed seems to be 45mph and 2400 rpm. After it's sat for who knows how long I think the best thing I can do is drive, drive , drive.

 

[lonegunman]

I will try that trick too.
I just bought an A3 with 3200 miles on it and 300 hrs. Everything works perfectly except that after about 4 hours into my trip the CTIS started reading [flat?]. The manifold would try to pressure up, make it to 5 or 6, then claim it is unable to pressurize the manifold. I measured the pressure on the tires, and they are all maintaining perfect pressure. When I stepped outside I noticed the manifold honking allot like a goose, so I just shut the CTIS off, as i didn't want any damage or strain done on the system.
A thousand miles later in my journey and the tires are maintaining pressure.
My steering is stiff too. I ran through the procedure in the manual, (closing the valve and cranking the wheel) but it didn't help. I'm also hoping it can be improved.

And congrats on your purchase. Have you checked the oil yet? My eyes had never seen clean motor oil in a diesel before.

Here are some tidbits I have gleened from my brief ownership of an A3.

1. The oil in mine is still pretty clean after almost 4000 miles. I changed it and drove from Georgia to Washington state. It was still almost perfectly clean after the trip and it used less than a quart.

2. I had the tac verified. The engine will easily rev to the upper limit. According to the spec in mine it would turn 2927rpm and the CAT guy registered 2929rpm. NOW, he did not hold the throttle for five minutes or anything silly, he briefly revved it hard to verify the gages. The Army says 2700 rpm is the max, mine is perfectly happy ay 2500 and gets decent mileage there.

3. CTIS is junk. If your is working that is because it is about to break. They work best when left off. When left off they cannot deflate tires or proclaim flats. I've driven a dozen truck with CTIS and it did not work on ten of them. Mine worked a bit longer than four hours but no much.

4. Power steering will need a little fiddling with. Mine was not working when I got the truck. Adjust the regulator. I emailed Erik from Erik's Mlitary Surplus and he gave me solid advice that got me on the road.

5. Erik's Military and Industrial Surplus - Military Vehicle Parts, Industrial and Military Surplus Electronics has parts and Erik is really helpful. He got me up to speed when I could not find a TO or anything on SS.

6. The really cool thing I learned about this website: On my cross country road trip I did not meet any SS guys in person. BUT, there were several guys who offered to assist if I broke down in their area. I offered to haul parts for a few guys but they could not get things arranged before I departed. A couple kept up with me thru my posts here and via emails. Just knowing you could find a guy who liked OD trucks and was willing to help made the trip a lot nicer. I have made the same offer to guys driving in my area, you never know when big green help is required. (Tan in my case)

 

[DeneMoore]

After 1500 miles, its still clean.

and I hope we find something about the steering. parking lots are challenge.

 

[AceHigh]

My A3 steering did not work till I removed the regulator and put oil into the system. Now it is like new.

 

[renovate7]

Just finished getting my power steering working! (!) When I got this truck I pulled the 3 lines on the drag link valve and 2 lines on the tie rod cylinder and put oil in all 5. No PS on 3 trips. Today I gave the regulator 3 full turns to the increase direction. I pulled the line from it to the drag link cylinder, added some more oil, and started the truck. I had good volume/pressure from this line so reconnected it and presto, power steering. I am able to turn the wheel lock to lock sitting still, can't wait to go for a drive. I think the increase from the regultaor is what did it but the oil doesn't hurt.

 

[SHBENNETT]

Thanks for all the help and post. I've got the truck running smooth and working pretty darn good if I might say. Couldn't have done it without the help of the people on this board.

Now, unfortunately, I have been given another assignment in a different state and will not be able to take the truck with me very easily. So, it's now back on the market!

Let me know if anyone is interested in coming by for a test drive or would like to take it for a spin. She sure does run great!