Lately my spirited drives and trips to Mexico racing league have been ruined with trying to find 5th gear. I need to find a solution or remedy to this. The detent that holds the shifter into the 5th/6th gate is weak and is very easy to overpower, and I end up in a dead spot between 5th gate and the reverse lockout. Usually doesn't happen if I'm gently going up in a slight rightwards diagonal, but the finness required ruins the driving experience.

I already checked and my shifter is "aligned": I have no problems with 1-4 gears, and I know it's aligned because 3rd is a straight push up and has no issues. My shifter is the stock C5 that has been shortened in a machineshop. I'm willing to spend $$ on a shifter if would resolve this, BUT my common sense tells me that unless the shifter has a built in detent for 5th/6th, it won't resolve anything. Please help, open to suggestions.

This is the ONE thing ruining my Corvette driving experience lately.

 

Detents are purely a function of the transmission. One of our members here has a good video on the T56 transmission where he talks about this (among other things).
He starts talking about it at 11:54, but specifically 5/6 and reverse at 16:00.

Basically I don't see any way you can improve that without transmission removal and some disassembly.

 

Check out the TMOD Customs Lower Box. The factory rubber bushings in the lower box are shot
by 50K milers or 10 years of age. I just replaced the lower box and shifter in my 53K mile 2007
(also have a 152K mile 99 C5) I purchased and had installed the custom lower box with his
20% reduction shifter. It is the Best Mod and should be the First Mod for any Manual
C5,6, or 7 (all the same lower box (C6 Zs use metal bushings OE)

The result is the best most direct shifting Corvette I have ever experienced!
Feels like a direct & precise "Bolt Action"

You may need transmission work, but I would absolutely replace at least the lower box first.
Much easier and less expensive than transmission work.

NOT JMO
Good Luck

 

I also have TMOD lower box. My opinion: it may worsen OP's problem. My TMOD box is tight enough that it binds a little bit, which could make the 5/6 detent less effective. Not saying replacing the lower box is a poor choice, I just don't think it will fix his specific problem.

 

what mph are you topping out 4th?... going into 5th is a serious race lol... if nothing else works, a taller rear tire and some more rpm would give you some more mph to hopefully long finish those races before the top of 4th

 

Not sure what mph but it was up there, I look at the road and tach at those speeds. Probably 140ish if I were to guess. It's not just that, it's that I usually like to coast down in 5th and not keep those RPMs so elevated for so long if I'm coasting down.

 

That was what I was afraid of. What doesn't quite make sense to me is that it's only the 5th/6th gate detent that's a little weak. 1st/2nd is fine, 3rd/4th is perfectly centered, and to move left from center neutral into the 1st/2nd gate position it's not that weak. And in the video you can see that it's only 1 spring and 1 detent ball, so I don't think it's the spring that's weak.

I've been even thinking to modify the assembly of the reverse lockout so it sticks further in a little more as to create that positive "stop" right at the 5th/6th gate, but this is going to require a lot of trial and error and might not even work well.

 

My 99 FRC is currently at 105k miles. I've taken my stock box out once and replaced the worn bushings by the polyurethane ones already once, about 25k miles ago. I'm thinking MAYBE the new lower box might help because if it's a shorter throw/shorter lever, I might be able to "feel" the detent stopping me a little better in that 5th/6th gate. Heck of a gamble at $475 though just to test to see if it helps or not. So this TMOD shifter is superior to the MGW?

 

Looking at the shift detent block from inside the transmission, to me it visually makes sense that the 5/6 position could be less noticeable:



Going from the 5/6 neutral position to the reverse neutral position, there's hardly a detent there. I wish they had made it a deeper notch. Perhaps that could even be a modification somebody tries: simply taking a ball end mill and deepening the 5/6 neutral detent. I suspect one downside is that it probably wouldn't return to neutral because the spring that controls side-to-side (as seen in the video I linked to) is kinda weak. Maybe a return spring could be added to a shifter to help it return to center from 5/6 neutral (when there's a deeper detent).

 

Makes a lot of sense, maybe my "weak 5th detent" is somewhat normal then after all. It doesn't help that I feel drag/friction when pushing to the right onto the 5th/6th gate from center-neutral, so as I try to over power the drag it makes it's easy to blow by the 5th/6th detent and end up in Reverse. I'm going to try just to clean and re-lube the shifter ball joints, shafts, couplers...etc. as to avoid any drag going to the 5th/6th gate. If that doesn't help, I might explore modifying the reverse lockout pin so it sticks in further and acts as the detent on 5th/6th, since it's not that far off in distance.

 

Update: Decided to take apart the stock lower box and shifter do a full cleaning and re-greasing of all pivot and rotation points. I greased everything really well, packed it with synthetic bearing grease, put it back together and realigned the shifter. The feel is way better, very silky shifter, very pleasent to row gears, and comes back to center neutral with no issues (doesn't drag or stick anymore), but still the 5th detent doesn't do the best job at stopping the shifter at the 5th/6th gate. It's certainly easier to find it because I don't have anymore shifter drag, but issue is still there. Not really an issue, just more of an inconvenience that 5th is not fool proof.

 

Finally got into upgrading my shifter and finally the problem of overshooting 5th is gone!!!! I got a very good used Hurst short throw shifter (with self centering springs) and it is an absolute pleasure to shift, for me at least. Getting to 5th is almost telepathic now. The self centering springs definitely help assist the weak detents of the trans. Feels like a race car now lol. I love it, and love going to 5th now with confidence!!!!

 

Have you added washers? The anti-venom mod? Adding those washers gave me the issue you are describing and I hated it. If you have....I suggest removing them

 

As I was reading each reply to your post, I was yelling, "Get a spring assisted shifter" LOL! I have a KIRBAN shifter and like you stated, its a pleasure to shift and shift with confidence. Some don't like the added force that it takes to move the shifter from left to right but I love the race car feel and precision. My shifter incorporates Shift stops and that too adds to the precise shift feel. When you hit the stop, you KNOW that you are positively in gear!
Like others have stated, there are things that can be done to our transmission shifter system to make it better. One is a better lower box, another is replacing the worn heim joints in the shift rod that attaches to lower box to the trans. They can wear and flex out of position during gear change. TMOD also offers an improved shift rod with improved joints. Most do the mod their selves.

When you shift the transmission, look at the rear of the lower box where the shifter shaft comes out and see if there is any slop side to side/ up and down. If there is, you could benefit from a new or better aftermarket lower box.

You already have the other improvement ; Spring Loaded upper shifter.

I'm glad that you have resolved your issue. When was the last time that you changed MN6/MN12 transmission (ATF) Fluid? I have found out that fresh ATF makes an improvement in shift feel and performance if the fluid is old and dirty. If you have a 2001-2004, any high quality synthetic ATF will work fine. If you have a 97-2000 I would recommend a DEXIII compatible ATF. You can use the AMSOIL Torque Drive ATF fluid in any year C5.

Bill

 

Trans fluid is fresh. Changed it before last weekend's HPDE: Amsoil Torque Drive ATF. I'd say my problem is solved now. Just have to get used to the extra force, but it's not too bad, but I might relieve the side-to-side spring load slightly. The Hurst has adjustable spring load for both left and right gates... Shifts are so precise now though. I'm torn on doing the antivenom mod now or leaving it as is. I'll drive it a for a couple of weeks before determining if to do the antivenom mod.