RTH: Anyone know what the temp of the rear diff housing s/b after a normal drive? (1 Viewer)

John McVicker

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BACKGROUND: ‘86 FJ60 with 3.70 gears. Me & a friend just completed a self install of ARB rear locker this weekend. Went for a 5 mile 60 mph drive and the rear diff housing seems to be too warm/hot to the touch...but really I have no info to say one way or the other. IR gun has temp @ 115*-118*. Think I have anything to worry about or does this sound normal??

To me that doesn’t sound too high but I’ve actually never tested the temp of the diff housing before so I don’t have any idea what is normal.

Prob being paranoid but I thought I’d ask if someone actually knows.
 
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BACKGROUND: ‘86 FJ60 with 3.70 gears. Me & a friend just completed a self install of ARB rear locker this weekend. Went for a 5 mile 60 mph drive and the rear diff housing seems to be too warm/hot to the touch...but really I have no info to say one way or the other. IR gun has temp @ 115*-118*. Think I have anything to worry about or does this sound normal??

To me that doesn’t sound too high but I’ve actually never tested the temp of the diff housing before so I don’t have any idea what is normal.

Prob being paranoid but I thought I’d ask if someone actually knows.

Mine gets warm but not so much to where you can’t touch it. Same locker, same gearing but I’ve never had the fancy IR gun
 
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Kleatus

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I wouldn't be worried about that temp at all, IIRC that is inline with what I saw during short drivea breaking in my rebuilt 3rds, and much much lower than I have seen on my pickups when towing.

That said, I'm not sure 5 minutes would bring the unit up to full temp. I'm assuming you retained the original gears?
 

OSS

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Where I live, the asphalt gets over 140°F during the summer. Sometimes over 150°F.
Can only guess the temps of every differential on every vehicle driving through. One things for sure... they're all way over 118°F
 

John McVicker

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Ok guys, thanks! I share your collective thoughts but wanted to get your opinions.

And yes James, I did have them unlocked for the 1st temp test @ 5 miles. And if you get around to a temp check on yours that would be great...but after what everyone said, I think we’re good.

I actually drove from Ca to my friends house in Az where we did the install. Put it all back together and immediately got on the road for the 9hr trip back home. I checked the temp after the 1st 5 miles and then at each of 4 fuel stops. Always 115*-118*. Again, thanks for everyone’s thoughts...just paranoid I guess.

And just as a side note...self installing a ARB Locker in the rear... for the 1st time...on your back...in a one car garage... with daytime temps starting out @ 38* is one ROYAL PAIN IN THE REAR.😳🧰🔧🛠
 

rhah

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Ok guys, thanks! I share your collective thoughts but wanted to get your opinions.

And yes James, I did have them unlocked for the 1st temp test @ 5 miles. And if you get around to a temp check on yours that would be great...but after what everyone said, I think we’re good.

I actually drove from Ca to my friends house in Az where we did the install. Put it all back together and immediately got on the road for the 9hr trip back home. I checked the temp after the 1st 5 miles and then at each of 4 fuel stops. Always 115*-118*. Again, thanks for everyone’s thoughts...just paranoid I guess.

And just as a side note...self installing a ARB Locker in the rear... for the 1st time...on your back...in a one car garage... with daytime temps starting out @ 38* is one ROYAL PAIN IN THE REAR.😳🧰🔧🛠

Glad you finally put them in, also means you have to hit all the trails now John
 

John McVicker

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Just kidding. Pic stolen from @rkymtnflyfisher 😆

CBFE6C67-022F-4AF2-BD7A-4E87DCAD72D6.png
 

OSS

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I'm think brand new gears run hotter for a while until they break in. A tech at a differential shop hinted to that when we were talking about gear lube and brand new gears - something to the effect that if a customer drove off their lot with brand new gears installed and bombed it to the next state (AZ) they wouldn't be doing the gears any favors.
I noticed when I first installed my 5 speed transmission, (30 years ago) it ran hotter for a while - especially on its maiden voyage, than my old 4 speed. Eventually it ran at normal temps after everything polished up inside
 

John McVicker

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^^^
Yea, I’m thinking that too. At least I did install all new bearings and used 85-140 wt for the drive home.
 
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