synthetic oil in my transfer case???

[riggermortis]

i was changing the oil in my transfer case and bought some red line 75-90 synthetic gear oil. what i didnt notice until i was ready to put it in and read the back of the bottle is that it says it might not be recomended for use in some manual trannies because it might cause gear clash. has anyone else heard of this and is anybody running synthetic in the transfer case with no problems??

 

[riggermortis]

i spoke to a guy who said that the synthetic is thinner so it will be noiser and to go with a heavier oil. i had purchased 75/90 so i took it back an exchanged it for 75/140, i put it in and have been running for a couple of days and it seems quiet and havent noticed anything as far as unusual noise yet.

 

[Bronc76]

Which t-case?

 

[Bully Bob]

R/U refering to the EB., or the F250...?

EB calls for SAE 50 above 10 deg. ---- SAE 30 below 10 deg.

However up there in the No. Tundra.., I doubt you'll get any noise.

Although., that seems a bit thick for winter ops.

----The computers at the China auto parts (AZ) list all the factory spec. lubicants, & are quite accurate.

 

[riggermortis]

sorry, it was for the dana 20 in my '67. i have been running the synthetic 75-140 for almost a couple of weeks now with no noise or prob. i have a factory '67 shop manual i guess i should have looked it up. just figured that anything that old took gear oil.

 

[Bully Bob]

".....just figured that anything that old took gear oil."

Hmmmm..., now you have me wondering..! Been a while since I changed mine but..,

I thought it was 50 weight "gear oil" (not motor oil)

NOW., I'm going to have to look it up........ :huh:

 

[Bronc76]

SAE 50 above 10 degrees, SAE 30 below 10 degrees.

 

[riggermortis]

i looked in my '67 ford bronco manual and i cant find where it says the weight of oil to use, all i can find is a capacity. i also have a "haynes" manual and all it says is manual trans and transfer case uses 140 weight oil. but it dont specify year or dana 20 or np 205. it does have a section for the dana 20 but thats all it says.

 

[Bully Bob]

Yep.., my '67 manual gives volume only as well.

My old Chilton repair man. calls out as above...SAE 50 or SAE 30

However.., I'm going to research this further., as I believe I have 80w gear oil in mine.

Rigg..,

THANKS for calling attention to this...... :-B >

B

 

[riggermortis]

the guy i talked to about it said that the synthetic 75-140 is about the same viscosity as regular 80-90 weight. the parts guy that i go to(not checker or autozone)is pretty knowlagable and he told me that one advantage of the synthetic is, that it doesnt change thickness with temp. that it stays the same viscosity in summer or winter.

 

[Bully Bob]

UP-DATE....

A top notch (one of many) EB store says,

"Bob,

You should be able to use either 80w90 gear oil or 50 weight motor oil. They have similar viscosities and properties. I don't know that I would bother with synthetic oil at all. It's probably a waste of money."

I take this to mean.., synthetic doesn't help or hurt a thing....just a lot more $$

***ALSO***

"the parts guy that i go to (not checker or autozone) is pretty knowlagable and he told me that one advantage of the synthetic is, that it doesnt change thickness with temp"

---If this were true..., it wouldn't be called 75-140 (75 being winter.!)

Might want to "call him" on that..... /emoticons/[email protected] 2x" width="20" height="20" />