Getrag F23 rebuild

I've got a problem with my '04 Cavalier's transaxle, pretty sure it's the synchros (it's much better if I double clutch). Whatever it is, I'm going to buy a salvaged unit and rebuild it. That way I can use a hoist at work over the weekend and be sure that I can swap them and be all done in the time I have. My question is, what are the differences between the F23 M86 and the F23 MG3? I know the MG3 used in the Saturn Vue is rated for about 400 lbs more GVWR (and presumably can handle a bit more torque), but is it even worth upgrading? I've got a supercharger on my car now, and plan on adding more power once I upgrade the internals, so there is a need for more strength wherever I can get it. I researched a bit and found the Getrag F23 is rated at 155 ft-lbs torque!? That's barely above the stock Ecotec, is that number right? If it is worth upgrading, are they interchangeable with no modification? I live 15 miles from work, and can't be without my car while I'm trying to fabricate something, so I really do need it to be nearly identical. I've heard that the '05s may have brass-tipped shift forks rather than the plastic in the older ones, any truth to that? If not, are there aftermarket brass shift forks available? Are there any places online to buy a rebuild kit?, I haven't found any searching.

Also, I'm an automotive technician by trade, but have absolutely no experience with rebuilding any kind of transmission. I've read quite a bit about the rebuild, and most people say it's fairly easy. I know nobody can answer this with any degree of accuracy, but given my above average mechanical ability, should I be able to do it without too much difficulty? (sorry, I hate these "can I ..." questions too :))

While I've got the transaxle out, I'm going to install some sort of performance clutch, but since I drive this car every day, I need one that isn't too grabby. Any first hand experience with "easy to drive" performance clutches? Is there really any reason other than faster revving to switch to a lightweight flywheel like so many places recommend? They cost more money than I really want to spend right now, so I'm thinking about staying stock there. No sense in revving faster when I can spin the tires through first and second anyway

I'm also thinking about a limited slip insert... as long as I'm in there, right? :) I thought someone here (pretty sure it was Cody) had one on their car and I was thinking it was not all that expensive. What kind was it and where'd you get it?

Thanks,
Jason

1) Stick with the F23 M86, the MG3 is geared differently. Geared more like a truck and will top out faster and less of a speed, I don't have the specs nor feel like searching for them. Sorry.

2) Not worth rebuilding them since the internal parts individually are expensive as fawk.

3) Clutch? -->Bully hands down and if your running as much boost as I think you are look into the stage 3 or 4. Contact pat directly at bully clutches since they are a Canadian company.

4) Look into a Quife Diff, Team Green LSD insert (JBO), Phantom Grip LSD Insert (www.Turbotechracing.com)

First we start with the input shaft. The order of major hard componants goes as such.

Left to Right: 1st Drive Gear, 2nd Drive Gear, 5th Drive Gear, 3rd Drive Gear, 3-4 synchronizer Assm., 4th Drive Gear.

http://img.photobucket.com/albums/v296/Xxway2fast4uxX/01%20cavalier/100_1165.jpg

-Facts to remember are 1st, 2nd, and 5th drive gear are cast as part of the input shaft meaning they always turn with the shaft, 3rd and 4th drive gears only drive at the speed of the input shaft when the synchronizer sleeve (which is splined to the input shaft) is locked into either gear.

Next we have the Countershaft.

Top to bottom: Countershaft Final Drive, 2nd gear #1 driven, 2-1 synchronizer Assm., 1st gear #1 Driven

http://img.photobucket.com/albums/v296/Xxway2fast4uxX/01%20cavalier/100_1166.jpg

-Facts to remember are, the Countershaft final drive gear is part of the shaft, 1st and 2nd #1 driven gears are only splined to the shaft via the synchronizer being engaged to the gears.

And lastly we have the output shaft.

Left to Right: Final Drive, Rev final driven, R-5 synchronizer Assm., 5th Final Driven, 3rd Final Driven, 4th Final Driven

http://img.photobucket.com/albums/v296/Xxway2fast4uxX/01%20cavalier/100_1163.jpg

-Facts to remember are, the Big gear just to the right of the Final drive gear spins freely on the shaft along with the 5th gear final driven until either is selected with the synchronizer sleeve. 3rd final driven and 4th final driven are part of the output shaft and obviously are always engaged with it.

1st Gear: Begins with the first gear from the left on the input shaft. Power is transmitted to the 1st gear #1 driven gear on the countershaft (Big one on the bottom) when the shift fork engages the 1-2 synchronizer into the 1st gear position. The gear is locked to the countershaft and power is transmitted through the shaft to the countershaft final drive which meshes with the second to last gear from the left on the output shaft. From there it turns the final drive gear which of course, turns the differential.

2nd Gear: The shift fork on the countershaft moves back out of first gear position and into second. The second gear from the left on the input shaft drives the 2nd gear from the bottom on the countershaft which is now locked to the countershaft via the synchronizer. Again it drives the Countershaft Final drive gear which meshes with the second to last gear on the output shaft transmiting power through the output shaft to the final drive gear, into the diff.

3rd Gear: Much simpler then 1st, 2nd, or reverse. 3rd is engaged by sliding the 3-4 synchronizer sleeve toward the left locking 3rd drive gear to the input shaft, this transmits power to the second to the last gear on the output shaft which again, is part of the output shaft, turning the differential.

4th Gear: Similar to 3rd the synchronizer sleeve is slid to the right engaging 4th drive gear and locking it to the input shaft. That gear drives the gear furthest to the right on the output shaft which is also part of the output shaft, Driving the output shaft and the differential.

5th Gear: 5th Gear is simple like 3rd and 4th however instead of locking the DRIVE gears to the input shaft they are ALWAYS part of the input shaft which means we have to Lock the DRIVEN gears to the output shaft. In this case the biggest gear (3rd in from left) on the input shaft is the drive gear, again note it is part of the shaft. Its mating member on the output shaft rotates freely until we slide the 5-R synchro towards the right. This locks the 5th Driven gear to the output shaft which turns the Final drive gear.

Reverse: Reverse is unique in this transmission since it uses 1st gear componants. The power flow moves from the first gear on the left of the input shaft, through the largest gear on the countershaft (which spins freely on the countershaft since the synchronizer is not engaged and it rides on the shaft with a roller bearing) This big gear then drives the Large gear 2nd in from left on the output shaft, but since there is an extra step in the gear train the output rotation is reversed. A good way to look at this is that an odd number of meshing gearsets will allow both input and output shafts to rotate the same direction, an even number of gearsets will allow the input and output shafts to rotate in opposite directions.

One install set of pics. (http://s268.photobucket.com/albums/jj19/italianscorpio75/LSD%20install/?albumview=slideshow)

My pics..

http://photos.imageevent.com/intimidator/jbody/P1010096_3.JPG

another pic of the fork and gear
http://photos.imageevent.com/intimidator/jbody/P1010099_1.JPG

all three shafts out and on the bench
http://photos.imageevent.com/intimidator/jbody/P1010109_1.JPG

all installed about to seal up and reinstall trans back in car
http://photos.imageevent.com/intimidator/jbody/P1010113_2.JPG

Make sure you use an anaerobic sealer between the housing or you'll get a fluid leak.

Seal PN - # 9120610

There is red lock tight on this bolt, use a torch and heat the fucker.

1) Stick with the F23 M86, the MG3 is geared differently. Geared more like a truck and will top out faster and less of a speed, I don't have the specs nor feel like searching for them. Sorry.

2) Not worth rebuilding them since the internal parts individually are expensive as fawk.

3) Clutch? -->Bully hands down and if your running as much boost as I think you are look into the stage 3 or 4. Contact pat directly at bully clutches since they are a Canadian company.

4) Look into a Quife Diff, Team Green LSD insert (JBO), Phantom Grip LSD Insert (www.Turbotechracing.com (http://www.Turbotechracing.com))


1. MG3 was like .83:1 I think and the M86 is .69:1... pretty sure (close anyway), but I found that after I asked here, definitely out of the question for a car that is on the highway 90% of the time and could use some more overdrive as it is. Although I know I'll never hit the redline induced max speed, which I think I remembered was 160-something?

2. Rough idea of the cost for new synchros and brass shift forks (if available at all) and where to find them? Any idea about the shift fork construction in the '05? Should the '05 fit my '04? If so I'll just get one from an '05 just in case they do have brass. I'd hate to swap a salvaged one and have it do the same thing in a year. When I got the car (first did it the day after I bought it) it would crunch a bit downshifting into third unless I double clutched or revved the engine to match speed, it got progressively worse, and I figured the third gear synchronizer was worn so I'd skip 3rd when it was convenient to make it last as long as possible. Then one day got to where it would grind into 3rd no matter what I did, and at the same time would crunch going into 4th unless I double clutched. I read on JBO that someone else had the exact same problem and it was the plastic on the shift fork breaking and falling off. I haven't used 3rd gear in a week, and skip 4th a lot of the time too. I get funny looks just driving along in traffic, accelerating normally, and shifting out of second at 5k RPM :rofl:

3. The MAP with the engine off reads 14.3-14.5 PSI, and at WOT at 5k RPM I have seen it read 29 PSI, so yeah I'm sure the factory clutch won't hold up for long, and I'm sure it slips a bit, even though I don't really hit the gas until the clutch is fully engaged. What stage do you have, and is it fairly easy to drive? I have never found a machine that I couldn't drive, so I suppose "easy" is relative...

4. I think my eyes skipped over the first digit when I saw the price last time! No way I'm spending that much on this car for something I'll only use for a few seconds at a time!

1) 145ish mph

2) No clue

3) I had a 4, you shouldn't be hitting 29psi. Most you should be pushing at WOT with that size pulley is 14-16psi (get yourself a boost gauge)

4) The quife is 1,XXX yea. The inserts are like 200-300 bucks.

It's not 29 PSI boost, it's 29 PSI absolute pressure (from complete vacuum) minus 14.3 to 14.5 atmospheric PSI = 14.5 to 14.7 PSI maximum boost. That's the reading on my Scan Gauge (has 4 user definable digital gauges that can display any 4 datastream lines from the PCM, and a crappy code reader that doesn't always work... but I didn't buy it to replace the Tech-2 or MODIS :)), as far as I know the measurement units can't be changed, but I'm getting used to subtracting 14 to get the boost. It would be nice to have a vacuum/PSI gauge, but for now absolute pressure will work.

I want to dismatle my GETRAG F23 (MANUAL) but I cannot open. Please give me some repair procedure and if possible with pictures. GOD BLESS YOU All.. Thank you all!!!