Manual Transmission Plugs

When coasting with no throttle, my truck will have a clunk and sometimes rapidly gain speed, or clunk and rapidly lose speed. My U joints are fine and freshly greased, but I want check/change my transmission fluid, transfer case while im at it and differential fluid. Any thoughts on what may be causing this?

The problem I'm having is, where and the hell are the drain and fill plugs on a manual transmission? I think Ive found them, but are they really on opposite sides of the tranny? I've never done a manual before, but I have plenty of automatic transmission experience from past vehicles. None of the many posts about how to do it and what fluid to use have pictures of the plug locations. Could somebody smarter than me throw some pictures up please? Ive no problem locating the rest of the plugs.

My truck is a 2002, 5-speed, 4x4. Maybe its important to know that it has had an engine swap from a blown 3.4 liter with 150k on it to a 3.4 with a 120k on it. Other than this clunk and speed change the truck runs, drives, and shifts beautifully. Clutch has less than 20k on it.

 

They are pretty obvious really... The drain will obviously be on the bottom of both the tranny and transfer. I think they will be a 24mm bolt. I have a different tranny cause I have a 2.7l but I'm sure they will be in the same position, fill plug should be on the left side of the tranny half way up and the fill plug on the transfer will be on the back of the unit half way up. They are all the same bolt and the head of the bolt is really skinny, they're also kinda a unique color to the rest of the surrounding bolt heads, if its not all nasty under your rig to see. Get under there and look closely they are obvious. 75-90 is what's to be used, I personally use redline mt-90 in my tranny and just plain ole 75-90 gear oil for everything else.

 

Actually, I think the tranny fill plug is on the opposite side on the transmission that comes with the 3.4 compared to the 2.7. I know the reverse sensor is on the opposite side. The drain plug on the t-case is usually not on the bottom, but on the bottom edge of the back of the t-case.

 

Oops sorry for the misinformation about the side of the tranny the fill plug is on OP!