Hello a couple days ago I purchased a 1986 Samurai. Everything's stock besides a missing backseat, top, new carb, door panels and tow along kit. It has 104,xxx miles and ill admit it isnt in perfect running order. It has some rust, ill post pictures below. My first concern is the areas of the rust, and the best ways to treat them. After treatment I plan on doing bondo work, covering the dash, removing the seats, and rhino lining the entire thing. Now mechanically, it runs ok. The day I bought it, it ran pretty good, but the cat conv was rusty. I drove it on the highway home more than 100 miles, and Im almost positive it blew some holes out of the weaker rust spots in the cat, causing an exhaust leak. Could this be the main problem??? It will run a little rough for a few minutes and then run smoothly.. not a big deal at the moment. But my main concern is the transmission. It's quit loud at higher speed and especially 4th and 5th gear. I'm almost positive it's the transmission, because riding in gear it's quiet, but it whines with the throttle. It's high pitched, kind of sounds like a bad bearing?? Just want to diagnose the problem asap. It seems to be louder with throttle in general. I know theyre noisy. But it seems like 4th and 5th gear cause the most strain on the main drive gear, so my guess is its the bearing for that gear?? Just throwing things out there to try and be specific as possible... The heat also doesnt seem to be working, and other than that the 4WD light is constantly on. I will try to trace the wiring from the instrument panel to transfercase but just wondering where grounds might be located? And theres also a stray red whire and nothing to connect to underneath the dash by the fuse box, could that be the cause of it? And lastly is it even a possibility that the cause of the light staying on is a loose ground?
I will say Im fairly young and I intend on doing all of the work on it myself. Even if it comes down to a transmission rebuild, I believe a good DIY and some common sense goes a long way.. along with extensive comments and suggestions from fellow enthusiasts and mechanics alike. thanks

Really shouldn't need to replace the connectors just clean the corrosion off. Removing the mounting screw and giving the connectors and the mounting surface a good cleaning should do it.

If you should happen to have to replace any, would recommend soldering them on not crimping them.

Glad to help

Thanks for all the help guys. I would have to say my biggest concern at the moment is the transmission. I have a reason to believe it is the bearings by the noise it's making. Is there any way to diagnose what might be wrong so I have a better idea of what to prepare for in fixing it. Thanks

You mentioned earlier being a manual trans, they have a flywheel and not a flex plate. The clutch can be worn/damaged and have loose components causing that sound, or a loose splash shield.

The transmission fluid must be GL4 or GL5 that specifically states it is yellow metal compatible or the synchros can be damaged. 

Usually in my experience noise on one face of the gear usually indicates damage to that face, do you have much noise during hard engine braking?

You mentioned earlier being a manual trans, they have a flywheel and not a flex plate. The clutch can be worn/damaged and have loose components causing that sound, or a loose splash shield.

The transmission fluid must be GL4 or GL5 that specifically states it is yellow metal compatible or the synchros can be damaged. 

Usually in my experience noise on one face of the gear usually indicates damage to that face, do you have much noise during hard engine braking?

Ah my mistake yes that's what I meant. And you're right I read some forum related, saying gl-5 lubricants eat away the brass and zinc. I asked advance what 'suzuki' recommended in their system, and all they had was a gl-4 and gl-5 compatible but I still strayed away as i dont qant to cause more damage. My guess is the previous owner had a mechanic who put gl-5 in it or something, damaging the bearings and causing the whining noise, could this be possible? My only problem now is finding gl-4 hah I went to advance, autozone, and a napa distributor. Advance and autozone don't even carry gl-4, at least the locations I went to. Napa said they might be able to order it but won't find that out til Monday. As for engine braking, are you referring to downshifting? Because it seems to only make the noise in 3rd to 5th gear, and only during acceleration. I see some residual oil on the bottom of the transmission so I can only hope that the other noises are caused from low fluid in the tranny

You mentioned earlier being a manual trans, they have a flywheel and not a flex plate. The clutch can be worn/damaged and have loose components causing that sound, or a loose splash shield.

The transmission fluid must be GL4 or GL5 that specifically states it is yellow metal compatible or the synchros can be damaged. 

Usually in my experience noise on one face of the gear usually indicates damage to that face, do you have much noise during hard engine braking?

Also the in the forum/thread I was reading it was talking about the bearings, are you saying gl-5 damages synchros as well?

The bearings and gears could care less if you use GL4 or GL5, it is only the synchros that will be damaged by GL5 because the synchros are of yellow metal construction, ie brass/bronze. Some GL5 gear oils are yellow metal friendly, including synthetics, but they must clearly and specifically state on the front label that they are yellow metal friendly, otherwise just go with a GL4, as they are all YMF.