how i fixed the hard shifting problem, by a new guy

JesseW.

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(long post warning)

little background on me and the car. I'm 24, a mechanical engineer, been around cars all my life. Helped my dad build his 5 second 1/8th mile (high 8's, low 9's in quarter depending on weather and gears) Camaro over several different build cycles and restored my 67 Nova SS when i was 15. this mustang is the 1st ford owned in the family.

I bought a 05 GT with 27,000 miles on it about 2 months ago. Vortech H.O. kit, JBA headers, Centerforce Clutch and Aluminum Flywheel, Eibach Pro springs. 440 rwhp. When i test drove it, it was really hard to shift, i knew something was up with it but bought it anyways because i knew i could fix the shifting and the car was a screaming deal. That weekend i killed the second gear syncro. I got a new takeout tranny from speedconcepts.net for $625 and put it in along with a hurst pro-billet shifter and new ford throwout bearing. Still really hard to shift, bled the system several times. it never helped.

Then i noticed that when i depressed the clutch over 2000 rpms, the rpms didnt fall, infact, the car slowed down like i had only let off the gas until it got to 2000 rpms, then the rpm's dropped really fast and shifted easily.

So i did some research and ordered a RAM slave cylinder/throwout bearing. dropped the tranny again and installed. I had to cut down the metal guide to keep from hitting the weights on the centerforce clutch, and played around with the spacers (ended up with 3 thick spacers) and now i can easily powershift 1-2 and 2-3 without a problem. no aftermarket mounts, no torque limiters. the clutch now fully disengages. It releases near the top of the pedal at idle, but at high rpms, the clutch releases after depressing the pedal 3/4 of the way to the floor ( because of the weights on the centerforce clutch)

I took my time and did it myself after reading some of the horror stories about the RAM slave on here and other boards. The biggest thing i noticed was most people let someone else install it who may not care as much about the install procedure and blew the o-rings out of the thing.

I believe this may be the majority of the shifting problems on this board (i've been lurking for a month and read most of the tranny threads) It is like another car it shifts so much better. I drove my friends mostly stock 07 with an MGW and stock clutch and it is much harder to make the 2-3 shift in than my new setup.

anyone need a ford tob with 300 miles on it? lol
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danbev07

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ah a fellow mechanical engineer :)

i'm studying to get there one day!

Please PM me with a price for the TOB ;)
 

08gt4u

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man my friends car is going through the same thing.the dealer rebuilt his tranny and while there he put a center force clutch.now the clutch engages really low and he says when his gonna shift it feals like if the clutch its hitting like a piece of metal.(maybe is hitting the weights)wonder if this will fix it.
 

US-1

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Gotta love the gathering of engineers on this board. Good to hear you made it work. Did you have a chance to measure the stacked thickness of the spacers?
 

JesseW.

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3 thick shims are .550 inch
3 thick 1 thin is .600 inch
2 thick 2 thin is .550 inch
2 thick 1 thin is .500
2 thick is .450

i used the 3/4 inch large spacer they sent that bolts up, then 3 thick shims and i cut the bar that the slave rides on by 3/4 inch. This worked for the centerforce dual friction clutch. pedal release is very high but clutch doesnt slip.

Clutch slipped with 3 thick 1 thin setup, and would not fully disengage with the 2 thick 1 thin setup. i had trouble taking the measurements off of the clutch to the block because of the weights so i kinda had to guess how many spacers i needed. this worked for my setup, may have to use a different stack of shims for other clutches

I like the mineral grey, i've never seen another grey one with red stripes either
 
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NA-Stang

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Civil Engineer here. Interesting that so many engineers drive Mustangs. Hmmmm.
 

sqidds

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Are the instructions with the slave any good or is it one of those deals where you need to toss them in the trash and figure out how to do it yourself?
 

JesseW.

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Are the instructions with the slave any good or is it one of those deals where you need to toss them in the trash and figure out how to do it yourself?


The instructions are pretty good, i think they had an equation backward on the sheet but it worked out anyways. i was very close the first time (within .050 inch) but it spooked me when the clutch slipped so i took too many shims out and worked my way up. i used the big spacer that goes behind the setup and the instructions never mentioned it, but it would have never reached the clutch without it.

i was worried when it said may not work with centerforce clutches on the directions, but i modded it to work :D
it was $368 for the thing, but the best money i have spent on it so far, i could barely put it in 1st or reverse at a stand still with the ford tob.
 
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soliton

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great wright-up, thanks for posting. I know some folks with the Hurst Billet, and they have a hell of time shifting. I have the same shifter, and shifting is a breeze. I am wondering if this could be the problem. However, they all have the stock clutch and flywheel (as far as I know)...

Hey, just curious, because you seem to know your stuff. Does your Hurst rattle? If so, have you found a way to fix that? It not a big deal, but mine does rattle. I thought I would ask. I know there are lots of previous threads on the topic, but I wanted to get the opinion of a mechanical engineer with previous successful fixes. :asskiss2:
 

Chris06GT

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Welcome to the site.....

Nice thread and write-up man....and the measuring of the shims was an excellent idea...

Just graduated with my 2 year Design Eng. degree.....now on to Mechanical Eng..
 

JesseW.

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great wright-up, thanks for posting. I know some folks with the Hurst Billet, and they have a hell of time shifting. I have the same shifter, and shifting is a breeze. I am wondering if this could be the problem. However, they all have the stock clutch and flywheel (as far as I know)...

Hey, just curious, because you seem to know your stuff. Does your Hurst rattle? If so, have you found a way to fix that? It not a big deal, but mine does rattle. I thought I would ask. I know there are lots of previous threads on the topic, but I wanted to get the opinion of a mechanical engineer with previous successful fixes. :asskiss2:

My hurst pro billet hasnt rattled yet, but i only have about 800 miles on the shifter, so time will tell. it is very smooth shifting for me. i didnt install the stops in it since the tranny has internal stops, that could be part of it.

This is where i orginally came across the RAM slave, with a decient install write up
http://www.musclemustangfastfords.c...s_hydraulic_clutch_release_install/index.html
 
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one eyed willy

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hmmmm,very interesting.i hate my 1-2 shift,feels just like what you said,i ordered a mgw and have not put it in yet.maybe i should order one of these two. do you know of any issues this set up would have with the spec 3+? how are the afctory lines run, i didnt take much notice when i pulled my engine, how was the bleeding?

btw..do you have a part number for that piece?rams website kinda sucks,i cant find shit!
 
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JesseW.

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RAM-78175
ordered mine from late model restoration. it was about $370 after shipping. american muscle was out of them.

I do not know about the Spec clutch, but would assume it would work because they do not have weights. the RAM instructions only mentioned Centerforce as a problem, and i fixed that!

As far as lines, it comes with 2, one pressure, one bleed. has an adaptor in the kit to fit the stock line. the bleeder is like a brake bleeder, have someone pump the clutch, crack, close, repeat till you have pedal. much better than that vacuum crap ford makes you do. just make sure you dont pump the pedal more than once before the tranny is installed, or it could over extend the slave cylinder and blow out the seal. blown seals were the biggest and only complaint i saw about the slave on the various mustang forums.
 

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