Process For Filling A T14

I have a cj5 with a t14 and a Dana 18 T case. My question is what the correct way to fill the transmission with gear oil. I know the trans and T case share oil but I have a fill plug and a drain plug in both. If I’m filling just the trans do I fill until gear oil
Come out the top hole?

 

yes

 

As I recall, the T14 and D18do not share oil. Fill each one independently to the bottom of the fill hole.

EDIT: As noted below, I recalled wrong and they do, in fact, share fluid.

 

And be sure to use GL4 (not GL5) gear oil.

 

X2

 

I do remember that I think I used sta-lube last time

 

Oil will migrate between trans and tranf case on that combo. Usually resulting in the trans low and transfercase over filled. PITA .
They do not make a sealed bearing for that application.I plugged the small holes below the mainshaft center line with a cup plug and a another with a piece of brass rod. This did the trick. When the transfer case gets over filled it it results in oil leaks . This was a common problem with the T90 also,but a sealed mainshaft bearing was available for that fix. mike

 

That’s what’s happening here becuse I took the fill plug off of the transfer case to top it off after it sat for 2 weeks and leaked all over the floor. When I did that oil came pouring out of the top hole on the tcase

 

Hey, it's just another total loss oiling system--------

 

Not to hi-jack, but what is the issue with GL-5? I just bought a gallon of 80-90 at my local old timey parts house that happens to be GL-5, but they told me it was fine for old stuff (gold parts). I topped off the T18 in my Jtruck with about a quart of the GL-5.

 

The flaps guys don't know what they are talking about. GL5 has additives that eat brass parts. It's true for modern manual transmissions also.

 

I have a 1970 cj5 with the t14/d18 combo.

My service manual says to use the following quantities/type of lube:

- 3 spd trans: 2.5 pints; GL4; SAE 90
- TCase: 3 1/4 pints; GL4; SAE 90.

after I replaced my clutch and reinstalled my transmission and transfer case, I followed these instructions to the letter.

However, after doing so, I could not feel the lube in the top fill hole of the transmission.

Now I’m also questioning whether I need to add more until it seeps out the fill hole.

 

More than just eroding the blocking rings it is too slippery and can cause all kinds of shifting issues. I’ve posted it countless times. More important I’ve discussed it with you in person

 

You did? My bad Usually the guys at Clackamas auto are fairly knowledgeable and they know what I'm working on. So will a quart of GL5 mixed with the STP GL4 I started with be a problem or should I just drain it and refill?

 

Interesting thread. I have the T14/D18 combo. They definitely share fluid. If I fill to the top of the fill hole on the T14 it will gush out of the D18 fill hole if I remove that plug. Also the D18 has an above normal leak rate. I wonder what the correct fill procedure is.

 

Tomorrow I’m going to try and pull the fill plug in the 18 drain out the excess, leave the plug out and fill the t14 until it comes out the top hole…..hopefully before it comes out the fill hole on the 18.

 

My suspicion is that you might get away with doing that, but if you came back and pulled the D18 fill plug 20 minutes later it will be over filled.

 

My comprehensive research has concluded that maybe, possibly, everyone here is right.

https://www.amsoil.com/p/manual-transmission-transaxle-gear-lube-75w-90-mtg/

https://www.amazon.com/Red-Line-503...locphy=1015072&hvtargid=pla-434001688696&th=1

GL-4 Specifically mentions brass parts...

https://lucasoil.com/products/gear-oil/synthetic-gear-oil/lucas-sae-75w-90-synthetic-gear-oil

GL-5 Does not..

 

fill transfer case to top plug - install plug
fill transmission to top plug - install plug
walk away - it's good
once driven the transfer case will be over filled - normal
all the spinning gears will transfer oil back and forth . but level in transfer case will be higher than fill plug

shared oil holes