M35A3 Owners unite

[rustystud]

Looking for some input on a M35a3 Front Winch issue.

So I have an M35a3 and my front winch will not engage and spool in.... so let's go thru what I have already been troubleshooting.

Broke out the TM and followed the step by step winch engagement steps..... no luck.

Made sure the Hydraulic reservoir was full and no leaks = check
Started vehicle with vehicle in neutral with parking brake engaged
Checked air pressure - good

Pulled out drum lock knob and I could free spool out the winch cable so no issue with a frozen winch drum
Moved winch clutch lever to IN
Engaged winch control lever in cab
Moved winch control switch to IN = Nothing

Tried variations on all of these combinations such as drum lock out or locked in, moved the Winch clutch to OUT and back to IN.

I could see the air controlled hydraulic "piston" right behind the reservoir move up and down but nothing else.

Yes I hit everything with a hammer.... multiple times.

Does anyone's Hydraulic pump engage and make any "noise"

Curious if my fellow M35a3 have any thoughts on the Winch issue?

I will be at Sussex if anyone wants to help and take a look at the Winch.

The Allison transmissions forward hub must be completely stopped before you can engage the PTO. To do this you must have it in gear and stopped. Then try and engage the PTO. After engaging the PTO put the transmission in Neutral. When the hydraulic pump is finally working you will hear it whine. We go through this problem all the time at work on our wreckers. According to the manual the air shift can be applied at anytime the transmission is in Neutral. This just doesn't work all the time.

 

[glcaines]

I had the same problem with my A3. Turns out, the air line to and from the "PTO" engagement lever on the shifter tower had been looped through with a 1/4" union air fitting bypassing the switch. Would have never guessed that and it took me some time of chasing things down. Could be worth a look in there.

Sounds like someone was trying to prevent people from using the winch or perhaps there was an air leak they were trying to bypass.

 

[tanker karl]

just got my 35a3 today,tankerkarl

 

[Floridianson]

The military used 15w40 in the trans for some odd reason. Mine still has the oil in it. Should I flush it out and replace with trans fluid?

Is the transmission giving you trouble. I talked to the Allison man and he said leave it alone as any kind of switch could cause a problem. If and when there is a problem then on rebuild we make the switch. Call you local Allison man and see what they say because there have been people that tried to switch and it caused a problem. You can not ever flush all the old stuff out. It's your transmission are you going to trust the internet or the Your Allison dealer?

 

[Floridianson]

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1325798

Now you can read this and believe them because it is on the web or call your Allison dealer. I have always found if there is not a problem do not make one.

 

[rustystud]

Is the transmission giving you trouble. I talked to the Allison man and he said leave it alone as any kind of switch could cause a problem. If and when there is a problem then on rebuild we make the switch. Call you local Allison man and see what they say because there have been people that tried to switch and it caused a problem. You can not ever flush all the old stuff out. It's your transmission are you going to trust the internet or the Your Allison dealer?

I agree. You will have a difficult time getting the oil out of the clutch plates. You can try and wean your transmission off the engine oil, but if it's working now then leave it alone. By the way I worked at Allison in Phoenix AZ. in the transmission department. So I guess that makes me an Allison man.

 

[Floridianson]

Yea and motor oil can go to a higher Tem. and not break down. Lighter weight oils can not so from what I have read because of the high engine speeds low ground speeds and heavy loads they decided to run motor oil. Even in any machine the Hyd. oil is half the temp. of the engine oil that is why you have to use high temp lines for motor oil and not Hyd. lines for remote filters and such.
Yea but I stayed at a Holiday Inn Express last night so that trumps all.
Rusty if something did got wrong with any exchange of oils would you stand by you Allison training and pay for the repairs.
http://www.machinerylubrication.com/Read/367/temperature-stability

 

[glcaines]

I switched to Dexron III several years ago. What a difference! Shifts up and down much smoother. I didn't contact an Allison dealer, I contacted Allison directly and talked with an engineer in their Technical Support Dept. I had a difficult time getting to one of their engineers since they are only supposed to talk to Allison dealers and not directly to customers, but they finally relented. He told me several things:

1. The Allison transmission in the M35A3 was specifically designed to be used with Dexron III. The military switched to motor oil to eliminate the need to support an additional fluid.
2. Dexron III is the only transmission fluid that should be used in the A3 transmission. Other Dexron fluids with a higher number are not compatible with the O-rings in the A3 transmission and will result in transmission failure.
3. The engineer suggested that a minimum of 5 drain and fills be made, driving several miles between, to switch to Dexron III from motor oil. Motor oil and Dexron III are not compatible.
4. Make absolutely certain that the transmission is not over-filled. Overfilling will result in the creation of foam, which will result in low fluid pressure and slipping clutches.
5. He also told me that Dexron III was de-certified by General Motors years ago. You can now only buy Dexron III compatible fluid. He recommended Valvoline Dexron III fluid, but told me to buy bulk NAPA Dexron III in 5-gallon pails instead of Valvoline since it was identical to Valvoline, being made by Valvoline for NAPA and was much less expensive.

 

[Floridianson]

I will take my chances with the MO that is in my transmission. Talk is cheap the transmissions are not. I have had not problems with the MO and yes the shifts are harder till she warms up. As said as long as the oil has a C-4 rating Allison said it would work.
Just believe that the OP's should know that a switch done wrong could cause more problems that leaving the MO in there.
The trucks were off road to begin with.
http://www.allisontransmission.com/parts-service/approved-fluids/off-highway-fluids

 

[rustystud]

I will take my chances with the MO that is in my transmission. Talk is cheap the transmissions are not. I have had not problems with the MO and yes the shifts are harder till she warms up. As said as long as the oil has a C-4 rating Allison said it would work.
Just believe that the OP's should know that a switch done wrong could cause more problems that leaving the MO in there.
The trucks were off road to begin with.
http://www.allisontransmission.com/parts-service/approved-fluids/off-highway-fluids

I stand by all the transmissions I repaired or rebuilt. As far as your continuing support of the military's use of engine oil I have nothing to say. You will never listen to reason or logic. I've supported all my statements with documentation before but you refuse to listen. Hydraulic oil will run at a higher temperature then regular engine oil. I don't know who told you it didn't , but their wrong. At one time doctors thought it was a good thing to bleed out their patients. I suppose you still believe that too .
Keep on using your engine oil in your Allison transmission. It will not last as long or shift properly but that's your choice.

 

[Floridianson]

To me it was just a warranty thing. When Allison was part of GM they had there GM approved fluid and you would void your warranty if you did not use there product and oil changed at the correct millage. When Allison split from GM the same thing, got to buy GM oil and change at there times or warranty is no good.
Allison now pushes the TranSynd (good stuff) with the family feud thing that has been going on since the split. As said the Allison can use many different oils for different needs. Here it was talked about some before. http://www.steelsoldiers.com/showthread.php?77746-Allison-Transmission-Fluid-Research

 

[Floridianson]

There is nothing wrong with the correct motor oil in a Allison.
https://fdlrd.swri.org/Allison/ApprovedFluidsList.aspx?Id=1

Hate to beat the dead horse but here is a Email from Mr. Johnson who was the Fluid engineer for Allison for many years.
This is why it pays to stay at a Holiday Inn Express.

 

[Floridianson]

I stand by all the transmissions I repaired or rebuilt. As far as your continuing support of the military's use of engine oil I have nothing to say. You will never listen to reason or logic. I've supported all my statements with documentation before but you refuse to listen. Hydraulic oil will run at a higher temperature then regular engine oil. I don't know who told you it didn't , but their wrong. At one time doctors thought it was a good thing to bleed out their patients. I suppose you still believe that too .
Keep on using your engine oil in your Allison transmission. It will not last as long or shift properly but that's your choice.

Yes Hyd. oil can reach high temp but that will be before the cooler could reach 300* You would not want Hyd. oil operating at engine oil operating temps. There would be very little heat transference and the trans would fail for sure. Guess I should have stated sump temps. as motor oil runs around 250* and the trans. from what people are posting sump temp as low as 175* My mind goes faster than my fingers and I don't get my point across.
Now I have a big problem you mean blood letting does not work. Also to believe a grease monkey or the Man who wrote the book Mr. Johnson. The facts mam just the facts.

 

[glcaines]

Yes Hyd. oil can reach high temp but that will be before the cooler could reach 300* You would not want Hyd. oil operating at engine oil operating temps. There would be very little heat transference and the trans would fail for sure. Guess I should have stated sump temps. as motor oil runs around 250* and the trans. from what people are posting sump temp as low as 175* My mind goes faster than my fingers and I don't get my point across.
Now I have a big problem you mean blood letting does not work. Also to believe a grease monkey or the Man who wrote the book Mr. Johnson. The facts mam just the facts.

Please refer to the attached document, put out by Allison and which covers the 1545 transmission. It lists fluids authorized for the transmission. Dexron III covers a larger range of operating temperatures. Another thought is how many 1545 transmissions have been produced, and most are in civilian use using Dexron III. Obviously, motor oil works in the transmission. I used it when I first received my A3. Which fluid to use is your decision and many agree with your choice. One further comment I have is that the Allison Technical Support Engineer also told me that Castrol Transynd was an excellent fluid but that it's only advantage over Dexron III was that Allison recommendations for fluid change intervals were extended for Transynd over Dexron III. Castrol Transynd is very expensive and not worth the money in my opinion.

 

[rustystud]

There is nothing wrong with the correct motor oil in a Allison.
https://fdlrd.swri.org/Allison/ApprovedFluidsList.aspx?Id=1

Hate to beat the dead horse but here is a Email from Mr. Johnson who was the Fluid engineer for Allison for many years.
This is why it pays to stay at a Holiday Inn Express.

This guy is from a wedsite not "Allison". Maybe he did work at one time on the SAE oil committee, that still does not have anything to do with the ON road Allison 1500 series used in the M35A3. I do know about the 9000 series off road transmissions used in Dozers and such and also about the "Obsolete" engine oils that could be used. There are NO engine oils today that Allison recommends you use in any Allison transmission, especially today with the newer electronically controlled units. If you had a paper or document from an "Allison" engineer then I would take notice but not someone from some other website.

 

[rustystud]

Now about Hydraulic oil. It must be able to reach temperatures of 250F and maintain that. Engine oil on the other hand has always been run at 10 (F) to 15 (F) above coolant temperature, which means about 212 degrees (F). So who ever told you Hydraulic oil is a lower temperature oil is wrong. Now to be fair in todays little High RPM turbo Charged Screamers the oil temperatures can be much higher and the manufactures usually recommend a synthetic oil which can sustain a 260 degree (F) temperature, with bursts of up to 500 Degrees (F) for a few seconds.

 

[Floridianson]

OK Rusty all the who has the biggest carrier bearings is a moot point. We all know how you get just ask CM Davis. Fact is I too have been a grease monkey most of my life but that was not enough for me as the ADHD will not allow it. Fact 2 is I bet 1/4 of this board can , will or have done everything you and I have done. Fact 3 Allison ok the motor oil as said because it was easer to carry one fluid. Now just more facts if we go by the manual and look at the outside temps then ether motor or Dexron should be used. The facts mama just the facts.

 

[rustystud]

OK Rusty all the who has the biggest carrier bearings is a moot point. We all know how you get just ask CM Davis. Fact is I too have been a grease monkey most of my life but that was not enough for me as the ADHD will not allow it. Fact 2 is I bet 1/4 of this board can , will or have done everything you and I have done. Fact 3 Allison ok the motor oil as said because it was easer to carry one fluid. Now just more facts if we go by the manual and look at the outside temps then ether motor or Dexron should be used. The facts mama just the facts.

First off, why make it personal ? I'm coming to this bringing information straight from Allison. I have actually worked for Allison. I have all the Allison manuals for this transmission and many other transmissions I have actually rebuilt. I have been giving you the "Facts" all along and you don't care ! If you like running your engine oil in your transmission FINE ! Nobody is going to get you and throw you in jail for it. So why argue about it so much ? The reason I'm trying to set the record straight is for anyone else who doesn't know better and decides to put engine oil in there transmission and finds out they ruined it ! As for "how I get just ask CM Davis", I will try and set straight any wrong information I see no matter who is spreading it. Yes I have experience and experiences that most do not have on this site. Does that make me some monster because I want to share it ? Honestly if there are any Lawyers or Doctors on this site who want to share their expertise I would love to get some "Free" help ! In fact there is a Electronic Engineer on this site who is helping me right now ! What I think this is all about is the fact that "most" guys think they can handle any mechanical problem no matter what it is, and when someone who is an expert in the field comes along and sets them straight it hurts their "masculinity" and pride. Well I'm sorry Floridianson if I hurt your pride, but like you keep saying "facts just the facts" .

I forgot to mention, in that page you copied it clearly states that any engine oil would only be used in "Off-road" applications. So you better not be driving that deuce on the road over 20 miles per hour. That is of course if you can find that engine oil which is obsolete now.

 

[Hoefler]

I did a four flush-out of the motor oil in my transmission when I first got it. I drained warm motor oil, then filled with Dex, then drove around till warm. Drained and did this 3 more times to make sure it was clean of motor oil. I have owned the truck now for 4 years and have had zero issues with transmission. My belief here is to make sure the transmission is completely free of motor oil and free of any mixing of motor oil and Dex.
Pete

 

[tobyS]

Wow, I don't want in the middle of this, but I'm buying an A3 with R and 3rd out. I'll be seeing what they have in it shortly.