SM465 fluid replaced but qs

[RootBreaker]

ok so my 1978 sm465 is nice and OLD... I replaced the NP205 gear oil few months ago and was easy...well I had a few brews and made a huge mess but that is a different story...
Pull drain plug... drain.... replace drain plug... remove fill plug and fill...

so now I have noticed what seems to be my trans making a noise in 4th or 3rd (however you want to look at it... L - 1 - 2 - 3 )

so I know I have a leaky mess (rear main and somewhere between trans and xfer.. so chocked it up to maybe low fluid.

First my googling got me this...
80/90 gear oil
3.5-4qts

Drained my trans last night and 7 quarts came out!!!!!! was a bit frothy too so most likely water? like said truck is 38 years old and I have owned it since 1988 and never changed the fluid.

so I put 4 quarts in it and wow it is actually harder to shift. Doesnt go into gear as nice meaning you can "feel the gears" when shifting.

so my question...
is 4qts enough?

lets start there...

 

[handloader90]

Sub'd.

 

[diesel4me]

It's been years since I did a SM465 gear oil change,but I do recall it taking one gallon of gear oil,and I ended up pouring it in through the shifter opening after spilling most of it trying to get it in with those squirt jugs using the filler plug..

Someone may have added some Lucas or other additives to improve balky shifting to help compensate for worn synchros or gears & bearings..and didn't remove any of the existing oil to make room for it..or it could just be lots of condensation build up inside over the years..

 

[dyeager535]

You fill it until it starts coming out the fill plug, that's full.

I never go by "capacity" except as an idea how much I should need.

Mine is hard to shift into gear for a few seconds until the fluid warms up a touch.

 

[RootBreaker]

yeah ill crawl back under there and look for the fill plug. I filled it through the shifter

 

[Bent77]

Yes to STP in the trans

 

[dyeager535]

yeah ill crawl back under there and look for the fill plug. I filled it through the shifter

Shifter in my case is much easier to fill from, just need to use the fill plug as the level. Would be nice to have one of the various tools for filling it through the fill plug opening, the bottles are just nasty to try and use.

 

[Bent77]

Yep. I have barrel pump. Works great