How is my 5th gear going out already?

**getcha01** · 05-10-2009, 04:19 PM

I just had a $3,000 bench build done by a very respectable company in st louis area called fastlane, they sell higher end sport cars and older redone muscle cars....anyways I had steel shift forks installed,hardened input/output shafts, billet keys,carbon syncros put in it, and the guy has built the same tranny's for 10 second cars he said and he said noway I will break it with my mods, and that my motor with 115,000mi would go before the tranny does....well in january I installed the fresh built tranny and a spec 2 clutch I think it was, and just last week I went to shift into 5th and it grinded when it went into 5th, thats the gear that went out in the first place last year....well I am super pissed, I been laid off since january and forked out an extra $1300 to get the hardened parts put in and now its messing up after just 5 months of driving it, and it hasnt even seen a racetrack yet....and then 3 days ago I was in 3rd cruising at 30mph and i put the gas down bout half way and the rpm's surged up but the car didnt go, then it caught and started going at about 4000rpm, and it does that in 3rd,4th,5th,6th gear, but in 1st and second on the gas hard it will grab good, i couldnt imagine the clutch is bad already?!?!...I have stock internals w,slp lid,msd wires,pacesetter LT headers,catless 3in Y pipe,MAF descreen,coolant bypass around T/B, stock 3:42 gears, built tranny, spec clutch...It had a huge difference in power after I installed the headers and took cats off and installed the 3in Y pipe....before it just wheel hopped halfway through 1st, and now after the LT's,Y-pipe,cat delete,clutch and tranny it goes hard but spins also till I hit 3rd, even in 2nd cruising at 30mph when I hit it, it will spin through the whole gear....do I need a stronger clutch? I ran 13.08 before I did any of the mods...im sure its capable of mid 12's now....and how can my tranny be messed up already without racing yet or beating on it hard?...it sucks, 5th gear isnt even beat on ever..and 6th is never used.......I am supposed to get it dyno tuned soon, but with not working yet and these tranny problems its going to be hard to get the tune done.....

**DIRTY JERZY** · 05-11-2009, 07:07 AM

could be the clutch I have heard mixed reveiws about spec

**Wesman** · 05-11-2009, 08:57 AM

Originally Posted by getcha01

I just had a $3,000 bench build done by a very respectable company in st louis area called fastlane, they sell higher end sport cars and older redone muscle cars....anyways I had steel shift forks installed,hardened input/output shafts, billet keys,carbon syncros put in it, and the guy has built the same tranny's for 10 second cars he said and he said noway I will break it with my mods, and that my motor with 115,000mi would go before the tranny does....well in january I installed the fresh built tranny and a spec 2 clutch I think it was, and just last week I went to shift into 5th and it grinded when it went into 5th, thats the gear that went out in the first place last year....well I am super pissed, I been laid off since january and forked out an extra $1300 to get the hardened parts put in and now its messing up after just 5 months of driving it, and it hasnt even seen a racetrack yet....and then 3 days ago I was in 3rd cruising at 30mph and i put the gas down bout half way and the rpm's surged up but the car didnt go, then it caught and started going at about 4000rpm, and it does that in 3rd,4th,5th,6th gear, but in 1st and second on the gas hard it will grab good, i couldnt imagine the clutch is bad already?!?!...

Thats your clutch slipping 100%. Sounds like another Spec clutch horror story, which I've seen on these forums countless times. Its also possible that you have a rear main seal leak, which would allow oil to get on the clutch disc and ruin it, causing it to slip.

Your 5th gear issue could also be related to your clutch problem as well. If the clutch isn't fully releasing, it will cause a grind into 5th. And seeing as you have clutch problems, I'd start with that before you condemn the transmission.

**getcha01** · 05-11-2009, 05:08 PM

Thanks guys, thats what I was thinking, I thought maybe it was the rear main, I know it leaks, because when my tranny was out, I was told that I may as well put a new rear main seal in...BUT I DIDNT...and now it leaks, prolly cause I had to bang so hard on my pilot bearing to break it in half to get it out.....once ive been driving for 20 minutes or so it will handle full throttle through 1st through 3rd....but cruising in 5th or 6th it will rev up till about 3,500 or so then grab, I put a spacer between the slave cyl and the tranny instead of putting a new flywheel in, and I wonder if it cam loose or something....I dont see how a new spec clutch and heavily built tranny would break before a engine with 115,000mi and a stock rearend that leaks fluid?!?!

**getcha01** · 05-11-2009, 05:10 PM

I also noticed im very low on rearend fluid, I was wondering if that could cause it to rev up real high in higher gears when under throttle, but when in lower gears its will rev normal at full throttle.

**Wesman** · 05-11-2009, 05:44 PM

Originally Posted by getcha01

I also noticed im very low on rearend fluid, I was wondering if that could cause it to rev up real high in higher gears when under throttle, but when in lower gears its will rev normal at full throttle.

Nope. The transmission and rear end can't slip period. If the trans is in gear, its in gear. It will transfer 100% of the power. Same with the rear, its either 100% or nothing.

You made 2 mistakes in your install: Leaving a leaking rear main seal and not replacing the flywheel.

The rear main seal probably leaked on the clutch disc, causing it to slip. Using the old flywheel will cause chatter, as well as engagement issues, since its the improper height relative to the slave cylinder. Any time you change a clutch on an LS engine, the flywheel should be replaced with a 100% new one.

Pull the trans down, replace the rear main and clutch, and you should be good.

**getcha01** · 05-13-2009, 12:53 PM

Well while my tranny was being built I got laid off so I couldnt get the stnls steel headers or the new flywheel or the spec 3 clutch, so I went with pacesetter LTs,spec 2, and the guy that built my tranny resurfaced the flywheel, he said lots of people think those cars you need a brand new one, but he said if its only wore between 5-10 thousanths, he resurfaces them and mine was 7 thousanths wore down so he had me put a 7 thousanths spacer between my slave cylinder and tranny.....I dont know if it matters but the night it did it, it was raining really hard and I was driving in a downpoor and couldnt go over 20mph and I went into a huge flooded part in the road that was as high as the bottom of my door, and about 2 minutes after that is when it started slipping....could that have been it?...It doesnt leake oil on the ground so I didnt think the rear main was bad....and also now when I slow down to a stop in nuetral my rearend or u joint makes these nasty clunking sounds....Im still laid off and I need to figure out a cheap fix, Im hoping its slave cylinder, cause the guy thought the seal in the bottom of my slave cylinder was going bad and he said to get a new slave, but I didnt, and im wondering if that could be it....the clutch pedal comes all the way up and it doesnt grab at all until rpm's hit 4,000...before when my clutch went out it slipped up higher rpm's but not at lower rmp, thats where im confused.