Sacar la caja de cambios por debajo

[Martín]

He preguntado a profesionales y aficionados por el tema y todos me han dicho que es imposible. Resulta que he encontrado este guión que adjunto explicando el proceso. Parece viable pero me gustaría conocer la opinión de algún experto del foro:

Removal Instructions of the 5 SPD Transmission from the bottom
STEP 1 Drain Both the Engine and Transmission fluid (remember the oil pan is the transmission)
STEP 2 Install Pieces of Wood or Sparkplugs where the Upper control arms and the frame meets. (this is done to release the spring tension against the control arms when removing the drive shafts and axles)
STEP 3 Raise the car off the ground. Using a lift is much easier but you can do this with Jack stands as long as you are careful to jack up the car high enough (with JACK STANDS OF COURSE)
BE CAREFUL as this care WILL SEVERELY HURT/KILL YOU IF IT FALLS ON YOU!!!!!!!! Positioning the Jack Stands on the beams of car just behind the Steering rack will work fine

STEP 4 Remove the hood and lay it upside down on top of the car (with a towel under it to keep from Scratching it!)
Click here for Saab 900 79-94 Clutch Replacement Instructions!

STEP 5 Remove the header Pipe and secure the Converter to the heat shield with a Coat Rack.
STEP 6 Remove the Turbo Support bracket ( If the car is a turbo)
STEP 7 Remove the two lower control arm bolts from each lower ball joint, loosen each inner CV Boot clamp and slide each wheel bottom out and install a piece of wood between the wheel and the lower control arm to make room for the transmission removal from the bottom.
STEP 8 Remove the tapered pin from the transmission shift rod. A tip here is to loosen the nut (8mm if my memory serves me correctly) down to the bottom of the tapered pin and smack the pin/nut together upwards to get them apart.
STEP 9 Cover the inner driver with a rag and a tie wrap. This will prevent dirt from entering the drivers.
STEP 10 No Real need to remove the oil filler tube here as they are old tubes are quite difficult to install once the transmission is put back in the car. Be sure to disconnect the Dip stick tube from the intake bracket to avoid breaking it.
STEP 11 Lift the engine up about 8 inches or so using the lifting ring located on top of the engine. You can use a couple pieces of wood across the wheel sub straight structures (the high point across each wheel well) A engine lift would be the easiest way but basically any kind of brace will work as long as it supports the engine and lifts it up enough to allow you to remove the front engine mount.
STEP 12 On all cars equipped with water-cooled Turbo's the cooling line will have to disconnected and moved out of the way.
STEP 13 Remove the skid plate and the cross-member in-order to allow room for the transmission to drop.
STEP 14 Remove the 13mm nut off the stud located to the right of the crank pulley. Most people forget that this nut/stud is there and when the transmission will not come out they wonder why. This can be a little annoying to get out but a very short 13mm wrench will allow you to access it fairly easily. Once you get the nut off and the transmission out you will definitely want to replace the stud with a short 12mm Head bolt though. In some cases the nut is very stubborn to get out. In these cases try using a very small pair of vise grip pliers to remove the nut.
STEP 15 Remove all 16 bolts. Leave a couple at the rear and a couple at the front to keep the transmission up.
STEP 16 Be careful to keep the transmission straight when lowering it out of the car. Doing this will allow you to avoid the aggravation of the trans getting hung up on things coming down. Lower the rear first and the rest will follow with no problems. The weight of the transmission may be a bit heavy for one person but a floor jack/transmission jack or two people can easily handle the 100.00 pound transmission.
STEP 17 Installation of the transmission is in Reverse of the procedure is the opposite of the details above. Several tips during the installation is to use the dowel guide pins as they will help a bunch. When installing the bolts be ABSOLUTELY sure to put a bolt in the passenger side right front corner which is where one of the dowel pins/Line up pins are located. There should be a washer and bolt in that hole to prevent oil leakage from that point. Remember to seal up all the passenger bolts with blue RTV as some of them access the oil from the transmission.

[Doctor NO]

Impresionante. En cuanto pueda, te lo traduzco.

[AG]

Ya hablamos algo de esto....Pero...Tienes elevador?

facilitaria mucho el trabajo.

Sacar el motor por arriba no nada dificil, y creo que trabajaras mas comodo que debajo del coche(claro que necesitas grua)

anda describe el caso un poquito mas.

[Jaabier]

Hombre, si se trata de una apuesta o una promesa a la virgen, pues vale, como si aparece uno que sacó el motor con una mano atada a la espalda...
Yo digo que no merece la pena, desmontar los tornillos que unen el motor al cambio ya es latoso con el motor fuera.
Lo más engorroso (para mí) de sacar el motor es quitar los palieres, y haciendo eso también hay que sacarlos, así que no merece la pena.
Además puedes aprovechar para revisar el damper, retenes, fugas varias del motor, etc.

[Alejandro GR]

Resel tiene un Turbo 8 sedan en su taller con el motor montado pero sin caja de cambios. No sé si la saco por debajo o no, pero desde luego que tiene motor y no caja.

Saludos

[torrens]

si que se puede sacar por abajo la caja , en algun sitio lo lei , intentare despertar la neurona dormida , de todas formas , la mejor opcion es la de jaabier , sacas todo y aprovechas para tener juntas, retenes y bomba del agua nueva , y te dejas de problemas durante muchoooooooooooos kms.
saludos y suerte

[JOSE]

Yo tenía que reparar la caja de cambios del mio y también encontré ese documento; pero aparte de que precisas elevador y algún otro aparato qur aguante la caja cuando la desmontas, creo que es más rápido, fácil y seguro sacar el motor entero. Entre dos personas son tres horas.

[Martín]

Bueno con este DIY no parece que sea necesario un elevador ni artilugios, por eso lo comento...

Una de las cosas que tengo pendiente son los silentblock de los trapecios y parece que los del superior del lado del conductor no se puede renovar con el motor puesto, así que tocará extracción.

Aparte de esos silentblock, el damper y bomba de agua, qué otros poyaques me recomendáis chequear... ¿?

[AG]

kit hermeticidad del cambio, necesario, reten cigüeñal, silentblocks del alternador....cuando me acuerde te digo mas.