TMOD Lower Shift Box Mod = Magic Box
Thread Starter
Instructor
Joined: Mar 2014
Posts: 111
Likes: 32
From: Cross Plains TN
TMOD Lower Shift Box Mod = Magic Box
Just wanted to put a quick review of the TMOD Lower Shift Box Mod out there for any of you Manual guys that haven't gotten Tom to work his magic for you yet..
I'll throw out a little back story that may help some..
I might have put 1000 miles on my car this year due to building a new house and various other distractions that kept it sitting in my shop instead of being babied. Frankly, didn't bother me much since I've always felt this car's shifting was not as good as it should be.
I did put in a new C6 Shifter, Box and **** early this year as well as Amsoil in the trans and 1 washer in the Anti Venom Mod. I felt this was much better than stock but still just not what I thought it ought to be. Reverse was somtimes difficult to hit and the 2nd to 3rd shift was less than positive feeling. All in all, I've just never gotten a satisfying feeling when rowing the gears in this car.
I talked to Tom at TMOD's and ended up sending him my old lower box to modify. It came back today so I figured I'd see if it could make a noticeable improvement. I was a little worried since my other box and shifter is brand new, how much difference can it really make?
I did a quick swap, cleaned the car up a little, fired up a nice cigar, loaded up some Stevie Ray Vaughn and went for little ride.. All I can say is: WOW, what a difference this mod makes! I'm serious, I was actually hoping to get caught by red lights so I could go through the gears! All the vagueness in the 2-3 shift is gone and the leaver just flows in the 4-5 shift. High RPM shifts are solid and quick now since the proper gate feedback is there.
Guys, if your looking for a solid bang for your buck mod on your 6 speed, This is it!
Tom, thanks for making my C5 something I look forward to driving now!
JR
I'll throw out a little back story that may help some..
I might have put 1000 miles on my car this year due to building a new house and various other distractions that kept it sitting in my shop instead of being babied. Frankly, didn't bother me much since I've always felt this car's shifting was not as good as it should be.
I did put in a new C6 Shifter, Box and **** early this year as well as Amsoil in the trans and 1 washer in the Anti Venom Mod. I felt this was much better than stock but still just not what I thought it ought to be. Reverse was somtimes difficult to hit and the 2nd to 3rd shift was less than positive feeling. All in all, I've just never gotten a satisfying feeling when rowing the gears in this car.
I talked to Tom at TMOD's and ended up sending him my old lower box to modify. It came back today so I figured I'd see if it could make a noticeable improvement. I was a little worried since my other box and shifter is brand new, how much difference can it really make?
I did a quick swap, cleaned the car up a little, fired up a nice cigar, loaded up some Stevie Ray Vaughn and went for little ride.. All I can say is: WOW, what a difference this mod makes! I'm serious, I was actually hoping to get caught by red lights so I could go through the gears! All the vagueness in the 2-3 shift is gone and the leaver just flows in the 4-5 shift. High RPM shifts are solid and quick now since the proper gate feedback is there.
Guys, if your looking for a solid bang for your buck mod on your 6 speed, This is it!
Tom, thanks for making my C5 something I look forward to driving now!
JR
Safety Car
Joined: Jul 2010
Posts: 3,995
Likes: 386
From: Chandler AZ
I remember reading about this in the summer, and had been trying to remember who or what the company was.
My car sometimes pops out of 2nd, and reverse or grinds.
Figured it was time for transmission rebuild but want to try this with remote bleeder and change transmission fluid to something else that might help.
Have a website?
My car sometimes pops out of 2nd, and reverse or grinds.
Figured it was time for transmission rebuild but want to try this with remote bleeder and change transmission fluid to something else that might help.
Have a website?
Thread Starter
Instructor
Joined: Mar 2014
Posts: 111
Likes: 32
From: Cross Plains TN
No website but he has some video of his process in the C5 Parts For Sale section of the forum. Search Performance Lower Shift Box.
His email is Tmodcustoms@gmail.com
1999corvetels1, while the popping out of gear sounds like something a little more than a worn shift box... the hard to find reverse and occasional grind is now gone in mine.
JR
His email is Tmodcustoms@gmail.com
1999corvetels1, while the popping out of gear sounds like something a little more than a worn shift box... the hard to find reverse and occasional grind is now gone in mine.
JR
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Great to hear of a mod that works as advertised. 
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Safety Car
Joined: Jul 2010
Posts: 3,995
Likes: 386
From: Chandler AZ
No website but he has some video of his process in the C5 Parts For Sale section of the forum. Search Performance Lower Shift Box.
His email is Tmodcustoms@gmail.com
1999corvetels1, while the popping out of gear sounds like something a little more than a worn shift box... the hard to find reverse and occasional grind is now gone in mine.
JR
His email is Tmodcustoms@gmail.com
1999corvetels1, while the popping out of gear sounds like something a little more than a worn shift box... the hard to find reverse and occasional grind is now gone in mine.
JR
If I don't keep pressure on the shifter holding it in 2nd it will grind and or pop out of gear.
Also going into 4th, I have to have a little extra rpm to have it engage with ease, if I shift into 4th at low or near idle rpm (let's say I'm on freeway cruising in 6th gear and cars slow down say to 50 mph or less, if I go into 4th it will grind a little.
If I blip the throttle and shift into 4th quick while the rpm is higher (just a few hundred rpm over idle) 4th engages with ease.
On reverse it's usually the first reverse of the day backing out of the garage and it seems it's engaged, but it will pop out and grind, so I go back to neutral and let off clutch, then press clutch again and it will go into reverse just fine.
My biggest issue however is getting into first at a red light, it takes finesse and sometimes just brute force.
Then other times the car shifts with ease, and doesn't have any of these problems.
I think remote bleeder (going to try putting on while drivetrain is together Katech bleeder) then change trans fluid then this box.
If still bad, then plan on doing clutch job and send transmission to RKT56.
Last edited by 1999corvettels1; Dec 20, 2018 at 11:14 AM.
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I forgot to mention that when it pops out of gear, it actually wasn't fully in gear, I've learned to "feel" for it, going into 2nd sometimes there is resistance and if I keep light pressure on the shifter holding it in 2nd and then let off the clutch pedal it then fully engages.
If I don't keep pressure on the shifter holding it in 2nd it will grind and or pop out of gear.
Also going into 4th, I have to have a little extra rpm to have it engage with ease, if I shift into 4th at low or near idle rpm (let's say I'm on freeway cruising in 6th gear and cars slow down say to 50 mph or less, if I go into 4th it will grind a little.
If I blip the throttle and shift into 4th quick while the rpm is higher (just a few hundred rpm over idle) 4th engages with ease.
On reverse it's usually the first reverse of the day backing out of the garage and it seems it's engaged, but it will pop out and grind, so I go back to neutral and let off clutch, then press clutch again and it will go into reverse just fine.
My biggest issue however is getting into first at a red light, it takes finesse and sometimes just brute force.
Then other times the car shifts with ease, and doesn't have any of these problems.
I think remote bleeder (going to try putting on while drivetrain is together Katech bleeder) then change trans fluid then this box.
If still bad, then plan on doing clutch job and send transmission to RKT56.
I know this as mine was doing the same.
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Joined: Dec 2013
Posts: 175
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From: Tuskegee Al
It is good to hear about your results. I have a lower box on the way and I hope that it will resolve my reverse difficulty when my car is cold. We will see. Which bushings did you guys go with? I chose delrin. I am curious about your impressions.
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From: Cunningham, TN
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Thread Starter
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Joined: Mar 2014
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From: Cross Plains TN
I used Delrin also, was a little concerned about introducing any vibration that wasn't there before. No issues at all.
Turn around was maybe 7-8 days... I'll be honest, I sent it on a Friday on the way out of town for a meeting and forgot about it for a few days.. Tom was excellent in communicating the progress and it was back before expected.
The Cold reverse issue for me is better but I don't think it's gone completely. I drove it a few days ago (maybe 45 degrees in the garage) and had to shift to 1st before getting a smooth reverse. From there it was all good.
JR.
Turn around was maybe 7-8 days... I'll be honest, I sent it on a Friday on the way out of town for a meeting and forgot about it for a few days.. Tom was excellent in communicating the progress and it was back before expected.
The Cold reverse issue for me is better but I don't think it's gone completely. I drove it a few days ago (maybe 45 degrees in the garage) and had to shift to 1st before getting a smooth reverse. From there it was all good.
JR.
Burning Brakes
Joined: Aug 2011
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From: Vancouver Island
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Joined: Dec 2013
Posts: 175
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From: Tuskegee Al
Update:
I installed my box yesterday and it was a straightforward job. i did not have a rubber boot on the foot of the box, so I filled the slot with silicone and put some on the box and set it in place. I then put a bead of silicone on the top and installed the shifter. I centered the box and tightened everything up. The shifts are smooth and going into reverse is the smoothest it has been since I bought the car. I haven't driven it yet and will post more info when I do. But, So far. I am impressed with this mod. I highly recommend this mod.
I installed my box yesterday and it was a straightforward job. i did not have a rubber boot on the foot of the box, so I filled the slot with silicone and put some on the box and set it in place. I then put a bead of silicone on the top and installed the shifter. I centered the box and tightened everything up. The shifts are smooth and going into reverse is the smoothest it has been since I bought the car. I haven't driven it yet and will post more info when I do. But, So far. I am impressed with this mod. I highly recommend this mod.