5spd transmission?

hey guys, got a 1988 gmc sierra with a 5 speed and a 4.3 and sooner than later that 4.3 is being junked for an ls1 :cool: My main concern is: Will that 5 speed transmission be able to handle this beast that i am connecting to it, or am I going to have to rebuild it, or get a new one all together? ANother question about the conversion is, assuming the 5 speed transmission is fine -- are the only things I need would be a complete ls1 engine and a painless wiring harness and I would be all set in the garage? Could someone help me out with all the materials? I want to be able to have everything and just sit in the garage working on it, not be online looking for the next part along the route, you guys know what i'm saying here? Thanks a lot you guys, this forum is a lifesaver for me dreams of the LS1. :lol:

I can answer some of that.. first off, the 5 speed you have, is granny geared, you'll just hender performance b/c you are shifting constantly. Get the 6 speed if you want something to pull that thing around good and have a good street truck geared ride. Also, if you do, get a good clutch, like a STAR or SPEC, centerforce clutches suck. You need a new clutch b/c of the extra weight from the stock ls1 to the truck. The stock clutch is made for 3700-3800 lbs car, not 4k+ truck.

You'll need to make your own mounts or pay allen (farmtruc) to make you some. You wont be able to keep the a/c unless you cut your crossmember some to allow the clearence. The 94 and up gauges work with the stock ls1 sending units, but i'm not sure about before that.. no one has tested to see.

On the full list, i'll let someone who has actually done it, tell you that, but i know you need custom mounts made up.

What vehicle would i pull that 6spd out of? a newer truck? or one from a vette?

Camaro/vette.. trucks dont have 6 speeds.

well the new chevy silverado for 2003 I believe has an optional 6speed stick, that's why i wondered.

i think maybe the SS does, but i dont think the regular fullsizes do. I'd still go ith a camaro/vette one. The trucks always get shifted on their gearing for manuals.

Best thing to do is pull the engine and trans out of there, the five speed won't last , that is if you get it connected to the ls1. like domeskilla said, get a good clutch, the stock ones suck.

when are you planning on doing this swap, it's well worth it and you'll never go back to TBI.



see ya,

allen

Because of money I am shooting for next summer -- seems like a long time, but there are a couple mods i still gotta get done with on it before i do the engine swap. Am I going to have to change the axle or anything on the truck? what about the drive shaft? will those be okay?

Allen what did you do for a wiring harness? Did you have that company u have posted on "links" make one for you or did u just mod out a harness yourself?

What did you do about the "anti-theft" device on the engine, who did you have remove it?

Did you have to get the PCM reprogrammed? if so who did that?

Basically i'll need:

- LS1 Engine + 6 Speed transmission
- Wiring harness Modded for my truck (does painless make one specific for my truck?)
- Anti-Theft device removed from engine
- PCM Reprogrammed?

Please mention any little minor details you came amonst while doing yours just so that I am aware of them when i do the swap. A good price estimate to do the whole swap: 4,000-5,000 if I get ahold of a good price on an LS1+tranny? Can I maybe get a transmission from SUmmit Racing?

About clutches, would I want to change out the flywheel also? Could you lead me to a good company that sells a nice clutch that would go right in to this that's a really nice one? I want to do it right as far as replacing the clutch now, because it's going to get put to the test every once and a while, you know how that is. :thumb:

Quote:

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Originally posted by BCOSSETTE@May 26 2003, 07:01 AM
Because of money I am shooting for next summer -- seems like a long time, but there are a couple mods i still gotta get done with on it before i do the engine swap. Am I going to have to change the axle or anything on the truck? what about the drive shaft? will those be okay?

Allen what did you do for a wiring harness? Did you have that company u have posted on "links" make one for you or did u just mod out a harness yourself?

What did you do about the "anti-theft" device on the engine, who did you have remove it?

Did you have to get the PCM reprogrammed? if so who did that?

Basically i'll need:

- LS1 Engine + 6 Speed transmission
- Wiring harness Modded for my truck (does painless make one specific for my truck?)
- Anti-Theft device removed from engine
- PCM Reprogrammed?

Please mention any little minor details you came amonst while doing yours just so that I am aware of them when i do the swap. A good price estimate to do the whole swap: 4,000-5,000 if I get ahold of a good price on an LS1+tranny? Can I maybe get a transmission from SUmmit Racing?

About clutches, would I want to change out the flywheel also? Could you lead me to a good company that sells a nice clutch that would go right in to this that's a really nice one? I want to do it right as far as replacing the clutch now, because it's going to get put to the test every once and a while, you know how that is. :thumb:

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may have to modify the driveshaft..i dont know thedifferences in the 5spd and t56 as far as dimensions.

cant answer for him but im pretty sure allen wired all his from the stock harness, just spliced in..he wrote a "write up" in the Reference section of the site...i looks pretty thorough. and allen is a "big man on campus" having LS1edit yourself helps a lot i guess..he does his own tuning and just removed VATS himself.

as far as summit and trannys...im sure they might can get you one but ill be pricey....around $2700 for tranny alone is a quote i got straight from jason chromer(GM)

Clutches....SPEC makes very goos clutches, in stages based on hp and tq. I got in on a group buy from SpeeDemon Motorsports a few weeks ago...new clutch(Stg 3/Carbon...i think its good to 650hp) with a new flywheel, if you hust buy the clutch setup you'll need to resurface the flywheel if you got it...my motor didnt come with a clutch setup, so i got a deal with a new flywheel (they run around $170 for stock steel flywheel) i'd only get a clutch from SPEC or maybe McCloud, but they are pricey...yeah i thought about the StreeTwin($1000)

btw....im LKiller over on FSC

Brandon

Allen used a 99 truck harness and spliced and modified it himself.