My manual shifter can be moved from side to side slightly even when it is in gear. This should only happen when a car is in neutral position, not in gear! (1999 FRC)
Also another strange thing about the shifter. When you put the car in neutral, you try to make sure that you're in neutral by wiggling the shifter from side to side and then you know you're in neutral. If I try to move it from side to side when it's in neutral, it requires significant force to move it from side to side.
ATTEMPTED SOLUTIONS SO FAR:
1. I did the anti venom mod which made shifting easier, but did not solve either of the two problems mentioned above.
2. I already replaced bushings, lubricate every signle piece and joint in the shifter assembly all the way down to the cable linkeage box. Did not help.
SUSPISION:
I believe that this is a bad bushing or something deeper into the transmission because the shifter assembly is solid and well lubricated. Also, the side-to-side wobble I described while in gear is not just limited to the shifter. When I move or wobble the shifter from side to side, the linkeage also does the same thing in harmony.
The whole shifter assembly all the way down to the linkeage box is solid and all the parts move together. The wobble is caused by something deeper in the transmission, I just don't know what it is or how I can fix it?

 

Sounds like you've done the reasonable things. It doesn't have to be inside the transmission -- the linkage shaft between the shifter and the transmission is a known slop inducer, with more than one solution out there, including modified units from TMOD Customs, and a DIY process with U-Joints replacing the flex fittings. Problem is, of course, both require the trans to come out.
Found TDOM's video of the shaft slop:

 

Moved to C5 Tech.

 

So would I be able to replace the rear flex fitting that's closer to the transmission by myself in my driveway? Because if I have to take it to a shop it wouldn't be worth the money personally.

 

I'd like to see a video of how much slop you have just to see it but I suspect that little clamp with the torx bolt through it that connects the shift linkage to the shifter box itself is loose. That's a common failure point for sure and I have experienced it myself.

As far as doing anything to the shift rod transmission side, you have to drop the trans and torque tube out of the car. This can be done in the driveway if you have the right tools, namely jacks and stands to get the car up high enough. Its much less awful if you have a lift you can borrow.

 

I know mine is all "tight", as I redid everything when I had the shifter assembly out. I have no problems going across the gate in neutral, and side to side "slop" varies by which shifting plane the lever is in. 3rd/4th, almost nothing, maybe 1/8 inch, 1st/2nd -- noticeable, more like 1/2 inch. 5th/6th about 1/4 inch. Having checked with the trim out, I know it's all in the rear somewhere. Car has 80k on it, BTW.

If the pinch bolt behind the shifter box is at all loose, side to side movement is very, very noticeable - a "trace" of looseness there and you will get at least an inch of side to side. Yeah, I found that out the hard way! The lever basically is centered in the gate - you should feel some effort (slight) going into the 1/2 or 3/4 plane.

Dumb question - this is a stock setup, right? Some of the aftermarkets have adjustable spring loaded "centering" and can be distinctly "stiffer" across the gate.

 

Use a pair of good size vise grips and lock down different parts of the shifter assy. The shaft that comes out of the lower box, the shift shaft behind the pinch joint and see if you still have the same slop after locking them down. You have a small bit of movement somewhere and it translating to that slop that you see. I agree with REDZG in that you may have slop in those universal joints. If you lock down that rear shift shaft and the slop goes away, you have the answer.

How many miles on the car?

Are you sure that you don't have any slop at the rear of the lower box where the lower box shaft exits the box??

Bill

 

160k miles Stock shifter. I also Initially suspected the little clamp with the torx that connects the shift linkage to the shifter box is loose, but that was actually not the problem. When I wiggle the shifter, that little clamp ALSO wiggles with it. It is not loose from the rest of the assembly. In conclusion the entire shift assembly all the way down to the clamp is completely fine and solid. It all moves in harmony as one single unit. The wiggle is caused by something deeper than that. Somethin that I can not access from the center console. I am suspecting the U joint which connects closer to the transmission deep in there.

 

You are probably past this point - but I installed the TMOD lower box and put everything back together and within a year noticed "a lot of slop" - opened it back up and found that many of the bolts had come loose. Put them back with blue Loctite and that was that....

 

Just a thought....did you pull the lower box out of the car and shake it to see if there is slop in the box? At 160k miles I can only imagine it's shot. I just replaced mine with a low mileage c6 box and the difference was extreme. The linkage shaft that holds the shifter in the old box with 129k miles was flopping around because the bushings were shot. This was not obvious with the box in the car connected to the trans linkage. The linkage shaft in the replacement box is stiff and does not move around at all when I shook it. My car is shifting perfectly smooth with the replacement box, even with a B&M ripper in it.

New box made a world of difference. Can't believe I waited that long to replace it.

 

Ok I’m looking to replace the shifter rod that is on top of the torque tube which connects from the shifter box to the transmission. How do I do that? I have a floor Jack and Jack stands and power tools, no fancy lift tho.

 

You have to pull the transmission off of the rear bellhousing on the torque tube to replace the linkage.