"Drill Mod" good or bad ??
Thread Starter
On The Tree
Joined: Apr 2002
Posts: 131
Likes: 0
From: Knoxville, TN.
"Drill Mod" good or bad ?? Referreing to, or course the infamous drill mod for the LS1 clutch hydraulics.
Getting a clutch installed soon, and the mechanic doing the install said he has done the drill mod on more than a few f-bods, and it has caused some to break gears, since the clutch then grabs instantly on release. He said he will do it if I want, but does not recommend it.
So bottom line, is the drill mod good or bad ? I thought it was pretty much a "must" for these cars from what I read
Getting a clutch installed soon, and the mechanic doing the install said he has done the drill mod on more than a few f-bods, and it has caused some to break gears, since the clutch then grabs instantly on release. He said he will do it if I want, but does not recommend it.
So bottom line, is the drill mod good or bad ? I thought it was pretty much a "must" for these cars from what I read
If you want a girlie lazy don't grab clutch, then don't do the drill mod. The drill mod will solve a lot of your high speed shift problems. The dude is right though, it will be harder on the tranny and rearend.
TECH Enthusiast
Joined: Sep 2004
Posts: 642
Likes: 0
From: Quad Cities, IL
I was under the impression that the drill mod would allow the clutch to release in faster intervals. for example when making a drag pass. Without it the fluid wont be able to cycle back around fast enough to be used for pressurizing the release of the clutch in the 2-3 shift (most notoriously).
Why will it make the clutch grab super fast/hard???
Why will it make the clutch grab super fast/hard???
12 Second Club
Joined: May 2002
Posts: 262
Likes: 1
From: Holiday, Fl.
I have never heard that before, but I had been wondering the same thing lately. I put a Spec stg.3 in about 6 weeks ago, and did the drill mod. Went to the track once with it and it worked great! Then on Xmas night while coming home from the folks I got on it a little to get some jerk in a prelude off my ***. Did WOT 3rd, hit 4th WOT, then went to let off and put it in 5th... and was stuck in 4th. I finally got it out of gear, but neutral felt like the shifter was full of rocks and I was locked out of 5th and 6th. From searching around sounds like I broke the slider keys. I will be getting it rebuilt with the steel shift fork and billet slider keys, but it seemed like alot of ppl had this same thing happen shortly after the drill mod was done.
I think your mech. may be right, but I just figure that means I have replaced the clutch restriction with the tranny as the next weakest link. Both will be better soon!
I finally got it out of gear, but neutral felt like the shifter was full of rocks and I was locked out of 5th and 6th. From searching around sounds like I broke the slider keys. I will be getting it rebuilt with the steel shift fork and billet slider keys, but it seemed like alot of ppl had this same thing happen shortly after the drill mod was done. I think your mech. may be right, but I just figure that means I have replaced the clutch restriction with the tranny as the next weakest link. Both will be better soon!
TECH Veteran
Joined: Aug 2003
Posts: 4,954
Likes: 1
From: Kent WA
The slider keys could be a problem with any hard shifting like you do when drag racing... especially with a grabbier clutch that is harder on the transmission. I say do the drill mod and the clutch, but also have some billet slider keys put in the transmission. That's what I'm doing... I want to be able to shift my car hard at the track and not have to worry about chewing up the slider keys.
I just had a Z06 clutch installed with the updated slave cylinder and had him do the drill mod. I haven't noticed any sort of abrubt engagement or anything of the sort. The clutch starts to engage maybe less than an inch off the floor but doesn't really grab until maybe halfway up. I don't see how the drill mod can hurt the transmission or rear any more than a stage 3 clutch from Ram or McCleod that grabs far harder than my clutch does.
Jason
Jason
Originally Posted by Tranzor_Z28
The slider keys could be a problem with any hard shifting like you do when drag racing... especially with a grabbier clutch that is harder on the transmission. I say do the drill mod and the clutch, but also have some billet slider keys put in the transmission. That's what I'm doing... I want to be able to shift my car hard at the track and not have to worry about chewing up the slider keys.
Trending Topics
11 Second Club
Joined: Aug 2003
Posts: 1,541
Likes: 1
From: Boring Green, Kentucky
Originally Posted by matts22
If you don't mind, or if someone else will reply...what's a rough figure on the cost of putting in better slider keys? Is that the only easy upgrade on the T56?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo 12 Second Club
Joined: May 2002
Posts: 262
Likes: 1
From: Holiday, Fl.
Originally Posted by matts22
If you don't mind, or if someone else will reply...what's a rough figure on the cost of putting in better slider keys? Is that the only easy upgrade on the T56?
Last edited by SStillSSmokin; Jan 14, 2005 at 09:33 AM.
The guy who's doing my trans right now said the billet struts have even broken. He thinks the issue causing it is the aftermarket shifters overshifting. I set my Pro 5.0 by the book and he said I need to back each bolt up 1/2 turn. You have me convinced to not do the drill mod now. go to d&dperformance.com if you want them. I'm spending about $650 for my overhaul with a new Z06 slave figured in.
12 Second Club
Joined: May 2002
Posts: 262
Likes: 1
From: Holiday, Fl.
I'm glad I did the drill mod, and recommend it. Your tranny will be able to handle it now and you have the shifter stops so you should be good to go. I will either be getting a Pro 5.0 w/stops, or I may try to see if I can drill and tap holes for stops on my factory Hurst shifter.
Alright, if it doesn't screw up normal driving I"m ok with it. Hell, it was a nightmare figuring out how to get the master out. Would I bleed it like normal or is there a procedure to bleed the master while its out?
12 Second Club
Joined: May 2002
Posts: 262
Likes: 1
From: Holiday, Fl.
Originally Posted by Redlinez
Alright, if it doesn't screw up normal driving I"m ok with it. Hell, it was a nightmare figuring out how to get the master out. Would I bleed it like normal or is there a procedure to bleed the master while its out?
Good Luck!
Originally Posted by SStillSSmokin
I have never heard that before, but I had been wondering the same thing lately. I put a Spec stg.3 in about 6 weeks ago, and did the drill mod. Went to the track once with it and it worked great! Then on Xmas night while coming home from the folks I got on it a little to get some jerk in a prelude off my ***. Did WOT 3rd, hit 4th WOT, then went to let off and put it in 5th... and was stuck in 4th. I finally got it out of gear, but neutral felt like the shifter was full of rocks and I was locked out of 5th and 6th. From searching around sounds like I broke the slider keys. I will be getting it rebuilt with the steel shift fork and billet slider keys, but it seemed like alot of ppl had this same thing happen shortly after the drill mod was done.
I think your mech. may be right, but I just figure that means I have replaced the clutch restriction with the tranny as the next weakest link. Both will be better soon!
I finally got it out of gear, but neutral felt like the shifter was full of rocks and I was locked out of 5th and 6th. From searching around sounds like I broke the slider keys. I will be getting it rebuilt with the steel shift fork and billet slider keys, but it seemed like alot of ppl had this same thing happen shortly after the drill mod was done. I think your mech. may be right, but I just figure that means I have replaced the clutch restriction with the tranny as the next weakest link. Both will be better soon!
Launching!
Joined: Jul 2003
Posts: 230
Likes: 0
The abrupt clutch action would be from a Spec, they either like being engaged or not. There is not much in between for them. The drill mod is a must, or high RPM shifts will be a problem.
RedLinez, how's it going man. Been a long time since we talked.
Will
RedLinez, how's it going man. Been a long time since we talked.
Will
