Check that t-case fluid :0

[N2BRK]

I spent a couple nights helping my buddy prep his LBZ for a local truck pull event coming up on Saturday. While it was on the lift, I said we should change his transfer case fluid. The truck has over 300k and he bought it CHEAP about a year ago. I got the "well maybe we could top it off but it's not a priority". Wanna guess how wide his eyes got when I opened the drain and less than an eye-dropper full came out?!?!?!?!?! It now has 3Q of 5w/30 synthetic motor oil inside. Yipes!

We did the LML hydroboost unit too and this is the first time I've done it on an LBZ and the first time I ran into the problem of not being able to shift from park after. Rather than pull it out and drill the hole larger, we found a cool video describing how to bend the contacts in the brake switch instead. Voila. Easy peasy.

The rest of the budget short list to prep her was completed:

sleeves
DHD centerlink bracket
new poly torsion bar bushings and lowered fully
gear lube change
leaf spring clamps
rear suspension stops
new hitch
wheels and MT tires off another truck
front jounce bumpers
Lift Pump
LML hydroboost

With the leftover time we have before Saturday, we plan to:
swap in a lock box off an old truck
5" bed stack just for the event
Weld up mounts and toss on a borrowed weight box - only so he can look cool AF with his side biz logo on it

This should be fun as hell come Saturday, and it's always fun to wrench with friends.

 

[shakenfake]

Why did you put 5w-30 instead of Dex 6?

 

[Chevy1925]

Why did you put 5w-30 instead of Dex 6?

Full syn 5w30 will lube the tcase well but not evaporate like atf seems to do in some cases.

 

[malibu795]

Yeah there was a big thread about tcase fluid years ago, the ATF would vaporizes even synthetic, 2qt is OEM level most would run 5w30 and 3qts

 

[2004LB7]

I put 0W20 in my LMM. Was thinking it would be closer to ATF

When I purchased my LLY, I checked the T case fluid when I got it home and was pleasantly surprised it was full. I guess it should have been expected as the owner has the maintenance records going back to when he bought it new. Had 286,xxx miles on it

Still considering pulling it out to inspect the pump rub and maybe installing a kit. Doesn't currently leak so I wonder of it has been taken care of already. Didn't see anything in the paperwork for it though

 

[N2BRK]

My lb7’s was full and it has a new cover on; magnesium though I haven’t torn it open to see if the pump rub kit was done.

In my LMM I went to 5/30synth very early on and it was clean as a whistle inside!

 

[malibu795]

I put 0W20 in my LMM. Was thinking it would be closer to ATF

When I purchased my LLY, I checked the T case fluid when I got it home and was pleasantly surprised it was full. I guess it should have been expected as the owner has the maintenance records going back to when he bought it new. Had 286,xxx miles on it

Still considering pulling it out to inspect the pump rub and maybe installing a kit. Doesn't currently leak so I wonder of it has been taken care of already. Didn't see anything in the paperwork for it though

ATF is roughly 7 weight, hydraulic oil is 10 weight
Power steering is 3-4 weight

 

[2004LB7]

ATF is roughly 7 weight, hydraulic oil is 10 weight
Power steering is 3-4 weight

Aren't they all measured on different standards so not directly comparable?

What standard does ATF and hydrologic oil fall in?

 

[2004LB7]

ATF is roughly 7 weight, hydraulic oil is 10 weight
Power steering is 3-4 weight

Aren't they all measured on different standards so not directly comparable?

What standard does ATF and hydrologic oil fall in?
View attachment 126881

Ok, quick Google search says ATF is typically around 7 cSt so right down the middle of the 20 weight SAE engine oil range

 

[TheBac]

2005? 2006? When Mike first brought up using motor oil in the Tcase.

 

[malibu795]

2005? 2006? When Mike first brought up using motor oil in the Tcase.

Somewhere back there that and adding an additional quart of fluid as well

 

[malibu795]

Ok, quick Google search says ATF is typically around 7 cSt so right down the middle of the 20 weight SAE engine oil range

Yeah rough numbers on the weights

 

[Chevy1925]

Where I see the vaporizing is high outside temps and towing in those temps. Tcase seems to vent a lot then but even still, not all of them have the issue.

The pumps inside these things are pretty rudimentary. I don’t think a thinner oil will hurt but figured I’d stick with what Mike stated.

 

[lutzjk913]

I’ve been running 5w30 full synthetic in my transfer case for over 100k miles

No issues. Always clean when drained and looks new.