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928 transmission swap out

Old 02-05-2011, 10:41 PM
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mark kibort
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Default 928 transmission swap out

Are there any good guides on DIY transmission replacement? be nice if there was something done by Pirtle.

be nice if it could come out of the car upwards through a hatch, and not disturb any of the suspension parts.
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Old 02-05-2011, 10:48 PM
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Rob Edwards
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Just cut out the rear passenger floor, you've got a cage to hold the car together.
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Old 02-05-2011, 11:44 PM
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Sure. You undo some bolts and take the damn thing out. Don't reinvent the wheel to avoid 7 bolts Mark. Just take it out like everyone else.
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Old 02-06-2011, 02:35 AM
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Ok, Ill dig in!
I figure ill support the transmission with a couple of cables up through the chassis and drop the suspension down. can I drop it enough with the brake lines and sensors attached, or do you have to drop it far enough down that the brake calipers have to be removed. (only 4 bolts total, i know)
I figure you losen the shift linkage coupler (clamp bolt , not that allen head) and the main clamp with the 8mm hex on drive shaft, and does that clamp slide back like the one on the front? Its only one bolt so I imagine you just slide it over the shaft when you install or slide it off the shaft to remove by moving the entire transmission aft. after that, it seems the thing will just drop down, right? I figure with the two cables holding the transmission i can swing it rearward to get it off the main torque tube shaft and the upper shift linkage shaft and then slowly lower it backwards, over the suspended suspension.

When we did all this at Andersons, I got a feel how to put all this together, but having the lift and several jacks with lots of hands, made the whole process seem pretty easy. Again, I have to listen to Mark A talk about how he does this on his back at the track in 2 hours. He is an animal with the wrench!
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Old 02-06-2011, 05:36 PM
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MK The WSM has a pretty good write up with lots of pics.....the bummer is it will change your rear alignment...but thats easy to adjust back
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Old 02-06-2011, 07:31 PM
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I just started it up to see how the torque tube noise sounded after a partial track day, and 200miles of street hyway driving. It really sounding pretty bad. dont know for sure that it is the torque tube, as the sound seems to span the entire length of the tube. when the clutch is put in, the howelling stops. let it out, the torque tube spins up and it starts making a lot of noise I wonder if it could be the release bearing, but the noise really seems to be the torque tube. Here is the question: if I just replace the transmission, is it really much more difficult to replace the torque tube later if the noise is really the bearing in the transmission? Is it easier in the long run to put in the transmission and torque tube as a single uniit. can you do this without doing a full clutch job (pulling the clutch out). Im thinking it might be better to do this, as there would be no fussing around with attaching the torque tube shaft to the transmission, while trying to manuver the transmission with cables/jacks, etc, when trying to attach the two on the car. I seemed to remember the transfer of the driveline on the new black racer, from the holbert car, by doing it this way.

the next question is that if I do just install the new transmission, and then later want to do the torque tube, how hard is that job? I suppose you have to do much of the same things because the torque tube at the transmission side, just cant just drop down, it has to be move rearward which means some transmission finagaling.

Thanks for any and all comments!

Mk
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Old 02-06-2011, 08:01 PM
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MK if you suspect the TT bearings or the clutch release bearings of making noise then remove them and replace them .
Wondering about if this or if that is only gonna lead you back to your tail
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Old 02-06-2011, 08:17 PM
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Yep. Its a big job to go back in, made easier if you've done it before, but not that much easier.

I replace the automatics with TT as a unit.

Manuals, just the box, but with great care / good control over the trans jack to prevent stress on input shaft. I manipulate the angle of the engine for accessing TT/Trans bolts, loosening MM bolts if nec.


The reason: easy to access the front TT / bell housing bolts on automatic. But clutch is in the way on the manual.
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Old 02-07-2011, 02:37 AM
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So, you cant get to the front torque tube bolts to remove it without removing the clutch? I would think a 1/2" swivel and the socket, might work.
seems like it would be easier to get the transmission back in as a unit.

I think I could rig up the straps and jacks to mate the transmission and torque tube together, but it sure seems like Ill need a torque tube as well.

I cant imagine that release bearing is bad, its only been in there as long as Ive had the new stronger pressure plate.

by the way, in the write ups of changing the transmission, why are the axles removed by removing the 300ftlb nut?? is that only the automatic as maybe it cant fit around the disconnected axles as it is lifted in and out?

Originally Posted by Landseer View Post
Yep. Its a big job to go back in, made easier if you've done it before, but not that much easier.

I replace the automatics with TT as a unit.

Manuals, just the box, but with great care / good control over the trans jack to prevent stress on input shaft. I manipulate the angle of the engine for accessing TT/Trans bolts, loosening MM bolts if nec.


The reason: easy to access the front TT / bell housing bolts on automatic. But clutch is in the way on the manual.
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Old 02-07-2011, 02:57 AM
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Rob Edwards
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Mark-

You can remove the front TT bolts w/o dropping the clutch, Jim Chambers did it here, using an HF 98802:

https://rennlist.com/forums/928-foru...l-chapter.html

I would remove the TT and tranny as a unit.


Loosen and remove the axle shaft nuts- 32 mm socket.

Lift car and drop exhaust

Undo both pinch bolts from the front coupler, slide it back.

Undo the front TT bolts

Undo the reverse light switch (2 barrel connectors, they pull straight out)

Undo the speedo sensor off the diff cover

As far as the half shafts, people always remove them. But maybe you could just undo them from the tranny output flanges and let them drop with the rest of the rear suspension. Might be a little awkward in getting them to 'clear' the tranny as the rear suspension is lowered, without a pair of hands to keep them out of the way.

Undo the half shafts (long 1/2" extensions with an 8mm hex socket is easiest)
It’s easiest to rotate the rear wheels so that the bolt you’re working on is at about 1’o clock viewed from the driver’s side or 11 o’clock on the passenger side. I use two long ½” extensions (12” and 20”) so that I can seat the allen socket in the bolt, and then get good torque on it while sitting on the ground outside the wheelwell.

Now that you no longer need the parking brake, undo the parking brake cable from the handle, pull the cable thru the sheath. Vicegrip clamp the sheath in the LR wheelwell and pull it out (PITA, it’s usually stuck in a mass of body filler, but it’ll come out)

Undo and hang the rear calipers

Undo the 19 mm bolts on the tranny to crossmember mount mounts, and pry the tranny/TT back off the roll pins in the bellhousing

Chain the tranny to the sway bar

To drop the rear suspension:

-Undo the upper shock mount nuts (6),

-Undo the rear swaybar droplinks at whichever end is easier.

-Disconnect the brake pad warning/ABS connectors in the barrel connectors on each rear hub.

-Undo the 6 bolts holding the front end of the lower control arms.

-Undo the 6 bolts (19 mm) holding the crossmember to the body.

Let gravity do its work.
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Old 02-07-2011, 03:44 AM
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Thanks Rob!!

I still dont get the large 32mm nut removal. are you saying below , that I can leve the axles in place and just manuver the transmission around the ends, maybe strung up to get them out of the way.

Originally Posted by Rob Edwards View Post
Mark-

You can remove the front TT bolts w/o dropping the clutch, Jim Chambers did it here, using an HF 98802:

https://rennlist.com/forums/928-foru...l-chapter.html

I would remove the TT and tranny as a unit.


Loosen and remove the axle shaft nuts- 32 mm socket.

Lift car and drop exhaust

Undo both pinch bolts from the front coupler, slide it back.

Undo the front TT bolts

Undo the reverse light switch (2 barrel connectors, they pull straight out)

Undo the speedo sensor off the diff cover

As far as the half shafts, people always remove them. But maybe you could just undo them from the tranny output flanges and let them drop with the rest of the rear suspension. Might be a little awkward in getting them to 'clear' the tranny as the rear suspension is lowered, without a pair of hands to keep them out of the way.

Undo the half shafts (long 1/2" extensions with an 8mm hex socket is easiest)
It’s easiest to rotate the rear wheels so that the bolt you’re working on is at about 1’o clock viewed from the driver’s side or 11 o’clock on the passenger side. I use two long ½” extensions (12” and 20”) so that I can seat the allen socket in the bolt, and then get good torque on it while sitting on the ground outside the wheelwell.

Now that you no longer need the parking brake, undo the parking brake cable from the handle, pull the cable thru the sheath. Vicegrip clamp the sheath in the LR wheelwell and pull it out (PITA, it’s usually stuck in a mass of body filler, but it’ll come out)

Undo and hang the rear calipers

Undo the 19 mm bolts on the tranny to crossmember mount mounts, and pry the tranny/TT back off the roll pins in the bellhousing

Chain the tranny to the sway bar

To drop the rear suspension:

-Undo the upper shock mount nuts (6),

-Undo the rear swaybar droplinks at whichever end is easier.

-Disconnect the brake pad warning/ABS connectors in the barrel connectors on each rear hub.

-Undo the 6 bolts holding the front end of the lower control arms.

-Undo the 6 bolts (19 mm) holding the crossmember to the body.

Let gravity do its work.
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Old 02-07-2011, 04:19 AM
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Originally Posted by mark kibort View Post
I still dont get the large 32mm nut removal. are you saying below , that I can leve the axles in place and just manuver the transmission around the ends, maybe strung up to get them out of the way.
There is no need to remove them. Just remove inside bolts from transmission and use zip ties to mount shafts to rear subframe so that they do not hang by outer joints alone. Try to avoid removing shafts from hub at all cost. There is very good change that bearing inner race will come out with shaft which is not good at all.

If you TT bearings need change just remove TT and gearbox as single package and carefully split them afterwards. When puting it all back together its much easier for example to adjust gear selector to exactly correct position when they are at floor as single package.
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Old 02-07-2011, 04:39 AM
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Agreed --- don't mess with the axles at the hubs, just the output flanges.
If you strap them up, vs letting them hang, it will maintain a better center of gravity for removing the rear cross member.

The removal of the front upper TT bolts is the place to start if you are going to remove the 5 speed with the TT.
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Old 02-07-2011, 05:47 AM
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While its possible to remove TT without taking clutch down its good idea to remove it also while at it. Unless it has just been serviced and you are sure pilot bearing etc is ok.
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Old 02-07-2011, 06:09 AM
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I did that on the last one we fixed this fall.

Pulled the clutch and lubricated the short shaft, which needed it.

That gave easy access to bolts. Better for torquing them in the reinstall, too, I think.

Supporting the front of the TT on an adjustable height stool, plus trans jack for the box, gave fantastic control over the unit to allow single person to do the job with less risk to the dog.

I had forgotten about the method for removal with clutch still installed --- will attempt that next time.

Jim Chambers' car is single disc, not sure if that gives more room?
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Last edited by Landseer; 02-07-2011 at 07:29 AM.
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