Differential

[Unimog66]

I have a m1084 and was wondering if the middle differential is supposed to be hot where you can’t touch it . The oil is good. Are these trucks ok to do some highway ?

 

[Ronmar]

If I can hold my hand on it for 5 seconds, that is around 150F. Shouldn’t be much hotter than that… is it hot in the middle or out on the end of the hubs.

heat is a factor of friction/load. Are the brakes dragging?

 

[Unimog66]

If I can hold my hand on it for 5 seconds, that is around 150F. Shouldn’t be much hotter than that… is it hot in the middle or out on the end of the hubs.

heat is a factor of friction/load. Are the brakes dragging?

the whole thing is hot , the other 2 I can put my hand on them but not that one. The brakes are ok

 

[aw113sgte]

the whole thing is hot , the other 2 I can put my hand on them but not that one. The brakes are ok

You said back, but that's the middle differential. I haven't noticed a temp difference and have looked with a thermal camera. The middle differential does have some extra components and maybe it would be hotter if having to work harder to match the torque split (different tire inflation?)

 

[Unimog66]

You said back, but that's the middle differential. I haven't noticed a temp difference and have looked with a thermal camera. The middle differential does have some extra components and maybe it would be hotter if having to work harder to match the torque split (different tire inflation?)

i will check the tire inflation. If I make a camper out of it do you think they are good trucks for highway use ?

 

[aw113sgte]

i will check the tire inflation. If I make a camper out of it do you think they are good trucks for highway use ?

Look up eco hubs if you want highway use. Stock they are at redline at about 60mph.

 

[Ronmar]

it isn’t possibly locked is it? If it were locked, like the center diff in an AWD when you go into mode, if would cause a lot of gear loading on a hard surface, do not use mode/4wd on hard surfaces…

when you select mode the TCU powers a air solenoid valve under the passenger dash next to the fan solenoid, to send air to lockup that power divider axle diff. When you de-select mode, this solenoid valve should vent that lockup air. If that valve were leaking, that would apply air and keep that power divider locked Which would explain the heat/load as a locked divider would not allow any escape of torque due to wheel rpm differences…

Test 1: disconnect the air line to the power divider axle. Any air come out of it? shouldn’t be any when not in mode.

Test 2; jack up a rear wheel. If the power divider isn’t locked, and you start the truck and put it in gear, like any open differential, all the torque should be able to escape thru that raised wheel. Same thing happens if you drive the truck over a steep hump, you will loose thrust when an axle lifts off.

If the lifted wheel doesn’t start spinning and the other grounded wheels try to pull the truck off the jack, the power divider is locked…

 

[Unimog66]

would like to change the oil but not sure where the plug is to fill it up can someone help

 

[GeneralDisorder]

It's on the back. The level is filled till it flows out the fill plug. Drain is on the bottom.... How did you check that is has oil if you don't know where the fill plug is

 

[Unimog66]

It's on the back. The level is filled till it flows out the fill plug. Drain is on the bottom.... How did you check that is has oil if you don't know where the fill plug is

I was translating from French to English for my husband , i Mistaken it for the wheel oil was ok . Sorry

 

[GeneralDisorder]

I was translating from French to English for my husband , i Mistaken it for the wheel oil was ok . Sorry

Ah I see. That makes more sense. No worries. Sorry about the communication gap. Have you tried having him type it up using Google Translate and then proof-reading what it spits out? Just a thought.

 

[Unimog66]

Ah I see. That makes more sense. No worries. Sorry about the communication gap. Have you tried having him type it up using Google Translate and then proof-reading what it spits out? Just a thought.

Thank you I will try that