Oil In Transfer Case

[lingr3]

Hi all,

Based on a lot of posts on this site, I decided to put 3 qts of synthetic oil in my transfer case. Since this was the first time, I have a couple questions about the change.

Is it alright if I added all three qts thru the top speed sensor hole?

My hand pump sucks and I am not confident I got exactly 3 qts in the housing, if anything I added a little more. Is it going to hurt anything if there is more than 3 qts (like 3.2 qts) in the case.

Finally, if I only use my 4WD maybe once in 5000 miles, do I still need to change the oil every 10K.

thanks

Rob

 

[S Phinney]

It takes 1.6 qts to fill the transfer case and you should use the Auto Trak II fuild from Gm. I haven't found anything compatible yet according to some fluid techs.

 

[05' Ditry Duramax]

3 qts of synthentic 5-30W oil in the speed sensor hole and call it good. You might not get all 3 in there but it will close. It makes a HUGE difference.

 

[Noreaster]

It takes 1.6 qts to fill the transfer case and you should use the Auto Trak II fuild from Gm. I haven't found anything compatible yet according to some fluid techs.

Auto trac fluid is only for the auto trac transfer case is only available on the 1500s so you shouldn't be using that in yours.
The 261/263 transfer cases came with Dex3 but there was a study that said Dex3 can evaporate & to use 3 quarts of 5-30w oil instead.

 

[PhilsLB7]

Finally, if I only use my 4WD maybe once in 5000 miles, do I still need to change the oil every 10K.

Auto trac fluid is only for the auto trac transfer case is only available on the 1500s so you shouldn't be using that in yours.
The 261/263 transfer cases came with Dex3 but there was a study that said Dex3 can evaporate & to use 3 quarts of 5-30w oil instead.

So what is the change interval when using the 5W-30?

 

[Noreaster]

10K I believe

 

[PhilsLB7]

So I am looking at making the change from Dex3 to 5W-30 soon and wanted to check a few things before I did.

1. Is this the speed sensor (see attached pic)?

2. Is there a torque spec for the speed sensor when I go to put it back in?

3. Do I need to put thread sealer on it?

Sorry for the dumb questions but I want to make sure I understand everything before I make the change. Last thing I want to do is screw something up. Thanks for the help!

 

[jlawles2]

Why not use the fill plug? Unless you have changed the T-case angle or clocking, it should be filled to the bottom of the fill plug. If you want to fill it without taking out anything important, reach on top of the t-case and find the rubber plug. Pull it, and you can fill it from there. That is the rear bearing snap ring cover. It is about 1/4" wide and 1" long. Easy to but oil through. That is how I filled mine.

I used the same gear lube in the t-case as in both diffs.

 

[THEFERMANATOR]

Why not use the fill plug? Unless you have changed the T-case angle or clocking, it should be filled to the bottom of the fill plug. If you want to fill it without taking out anything important, reach on top of the t-case and find the rubber plug. Pull it, and you can fill it from there. That is the rear bearing snap ring cover. It is about 1/4" wide and 1" long. Easy to but oil through. That is how I filled mine.

I used the same gear lube in the t-case as in both diffs.

The fill plug is known to be too low of an oil level for the 261/263 transfer case, so it is reccomended to overfill it by a quart through the speed sensor hole. AND NEVER RUN GEAR OIL IN IT! EVER! The pump cannot pump gear oil through it and WILL self destruct it in a matter of a few hundred miles or so(or one cold morning). Gear oil is designed to be pumped as it is very thick, espescially when cold. The 261/263 transfer case relies on the oil pump that is mounted on the output shaft to pump oil to the mainshaft and planetary gear reduction unit. Without it the top end will not oil unless you are in 4X4. As for what oil to use, the DEX3 is believed to evaporate at high temps like those the transfer case can see. So a high quality(prefferably a diesel rated synthetic) 5W30 oil is reccomended. I persoanally run AMSOIL SYNCHROMESH fluid in mine, and am as happy as can be. It has almost the same viscosity to it at 0 degrees as ATF, has a slightly higher viscosity to it at operating temps, and has special additives in it designed just for manual shift syncros. It was designed for the NV3500 and NV3550 that DODGE and JEEP used(GM used ATF in this trans in there apps, but I notice GM had alot more failures than DODGE did with syncros), as well as some early FWD DODGE cars. it's readily available at most parts stores to boot.

 

[TeaBagger2006]

???I run tranSyn in there????
It's been bout 50k no problems

 

[MMLMM]

RUN factory recommended fluid, amount and interval

or

Run 3 quarts of Synthitic 5w-30 motor oil filled thru the speed sensor hole.


These are the only 2 options you should consider, EVER!
Nothing else, no other tip Jeb down at the cafe told you.

 

[JD4440]

I do too but it's about to be 5-30 per MikeL.

 

[S Phinney]

Gm recommends Autotrak synthetic. At least that is what shows up on the computers why I'm at. I've ran it for 200k miles and haven't had a failure. I haven't even had a pump rub problem. Just rebuilt it recently and found a stretched chain.

 

[THEFERMANATOR]

Gm recommends Autotrak synthetic. At least that is what shows up on the computers why I'm at. I've ran it for 200k miles and haven't had a failure. I haven't even had a pump rub problem. Just rebuilt it recently and found a stretched chain.

GM also released a TSB stating not to run AUTOTRAC in the HD unit's, but instead to run there manual trans fluid(DEX3, but since DEX3 isn't anymore they call it manual trans fluid). SYNCROMESH is a 5W30 oil, but it has a slightly thinner viscosity when cold and was designed as a dexron III substitute to improve cold shifting and synchro life. TRANSYND will work as well since it is a DEX3 compatible fluid.

 

[x MadMAX DIESEL]

I don't think I've ever changed my transfer case oil? Dex can evaperate??? WTF I may not even have any oil in it then?

 

[PhilsLB7]

Wow . . . this is a lot of good information. Thank you!

But can someone also answer my "dumb" questions (see post #7).

Again want to make sure I understand before I mess something up.

Thanks again for all who have posted.

 

[THEFERMANATOR]

Wow . . . this is a lot of good information. Thank you!

But can someone also answer my "dumb" questions (see post #7).

Again want to make sure I understand before I mess something up.

Thanks again for all who have posted.

Yep, that's the speed sensor you have highlighted. It has an o-ring on it, so no sealer needed. And it just needs to be snug in there, not tightened down as it is only plastic.

 

[PhilsLB7]

Yep, that's the speed sensor you have highlighted. It has an o-ring on it, so no sealer needed. And it just needs to be snug in there, not tightened down as it is only plastic.

Thank you sir! I think I am going to try to get some of the AMSOIL SYNCHROMESH fluid and try it. Checked it out on line and looks like good stuff.