First M35A3

[YOUNG GUN]

I'm new here so hopefully I'm posting this in the right place.

A few weeks ago I picked up a 1996 M35A3, and i've gone through all the fluids at this point.
I've been driving it quite frequently (5 days a week and around 60 miles each time).
The transmission temp has been running anywhere from 160-200 and the 200 was max in stop and go uphill traffic.
Today I finally decided to take it for a little off-road tour in some mud (nothing serious though) no tire spinning high rpm stuff, I took it pretty easy really, some low range stuff with the air locker engaged, etc.

I'm trying to describe what I was doing, but maybe I'm rambling now.

Main point of this...my transmission temp reached 275!!!
The TM says 160-200 I believe, so this is way over that.
I've searched other posts and haven't had much luck finding a similar issue.

Any suggestions, help, etc. would be greatly appreciated!

Thanks in advance

 

[autigers35a3]

Change the oil in the trans. Change both external and internal filters.
Consider going with DEXIII for trans fluid.
Erik's has both filters.
The oil in your trans could be very old .
How many miles on truck?
Search engine here is great.
You will probably be told very soon by many A2 drivers to check the search...
Good luck!!!

 

[gimpyrobb]

welcome to the site, certainly sounds like something is wrong, hope its just the filters.

 

[goodguyzy]

shouldn't go over 225, no A3 is high mileage. sounds like a filter. please add your city also

 

[YOUNG GUN]

- 10,500 miles and 345 hours on the truck
- I'm planning on changing the trans fluid and filters this week, even though the fluid looks fresh.
- I'll try searching some more, but I haven't seen the same issue yet.

I've seen some guys get blasted pretty good on here for posting a question that's already been discussed, so I'm reading all the TM's and searching threads for info

Thanks for your help!

 

[YOUNG GUN]

Also, after about 20 minutes of 40 mph driving (back home), the temp dropped right back down under 200??? I don't understand, but we'll see what happens after new fluid and filters.

Thanks for all your suggestions, and the warm welcome.
I've been looking around on here for a while, and this forum contains a wealth of knowledge.

 

[gimpyrobb]

Get an infrared thermometer and verify the temp? Maybe the sending unit is going out.

 

[goodguyzy]

how about your cooling fan? does it ever come on? did I pass you on hwy 97 a few months ago? you were heading north

 

[YOUNG GUN]

@Gimpyrobb: I've got an infared temp gun, so I'll do that tomorrow.

@goodguyzy: It couldn't have been me, I've only had my truck for a few weeks. I am however over that way fairly regulary. Where is the cooling fan located? I didn't think there was one besides the engine fan on my truck, I'll take another look.

 

[goodguyzy]

well the engine fan I should of said, does it go on and off as it should

 

[YOUNG GUN]

Are we talking about the large fan that runs directly off the front of the engine?
If so, it's always on... I thought they were suppose to run when the engine is running.

 

[goodguyzy]

when the engine reaches 225 it comes on, you will defiantly hear it. when driving you will also notice a power loss. I'm still no expert but it is pneumatically operated

 

[CobraCDR]

Let us know if the filter & fluid change helps. Welcome to the club.

 

[YOUNG GUN]

Thanks, I'll post results after I complete the services and get the truck back out for another off-road run.

 

[Thunder in NWOR]

Download from www.allisontransmissions.com the following:
Operator's Manual OM1334EN
Mechabuc's Tips MT1321EN

These manuals address your issue - and resolution.

and welcome to the world of the a3...!

 

[YOUNG GUN]

"Converter Out Fluid, Maximum" @300F

"Sump Fluid, Typical Continuous" @200F

Which location does the A3 take the transmission temp from?
I looked in the TM's with no luck.

Thanks

 

[ranchhopper]

Dont know much about A3s but if it has an external oil cooler you might want to make sure its not clogged with oil and dirt in between the fins it seems like it only cools at road speeds.

 

[srodocker]

welcome aboard and you should defiantly come to one of our mini rallys up here in washington!

 

[glcaines]

When I first recovered my A3 the trans temp gauge hovered around 150 for normal highway driving and about 200 - 225 for stop and go traffic. Once I switched to Dexron III, it dropped to 115 - 225 for normal highway driving. With the Dexron III and short trips of less than 10 - 15 miles, the temp gauge doesn't move and stays near the 100 mark, which is the minimum gauge temperature. It takes a number of miles for the transmission to come up to temperature. That being said, when I get in very heavy stop and go traffic in warm weather, it will shoot up to about 175. When the fan comes on, it very quickly drops to about 150 while still in the traffic with the fan running. When the fan goes off, it quickly again rises to about 175. Returning to highway speeds, it drops back to about 115 - 125.

Your cooling fan should not be running all the time. If it is, you need to troubleshoot it.

 

[YOUNG GUN]

Sounds similar... so far in very heavy stop and go traffic (1.5 hrs straight one day) trans temp was 200, but thats the hottest its been on the road, typically it runs about 160 (even in fairly slow traffic).

Then the first time off road...VERY slow driving, low range, and front diff locked in... temp hit 275 but did not go any higher. Once I got back on the road, it cooled off back to 160 in about 15-20 minutes.

I was taking it really easy, so its hard to imagine that it would get that hot?

Sounds like I have some fluid and filters to change, and some other things I need to look at, like the fan operation, and the trans cooler.

Again, thanks for all the help everyone.