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Transmission removal pointers

Discussion in 'The Garage' started by dammit32, Nov 17, 2005.

  1. dammit32

    dammit32 1/2 ton status

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    Hey guys :)

    My tranny gave up yesterday so I am starting to remove it. I have a 3" Y-pipe exhaust that goes over the rear part of the tranny pan. Does the exhaust have to come out?
    Are there any other things i should be watching?
     
  2. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    First things first -- Don't drop it on your head! Last thing that'll go through your mind will be your eyeballs!

    Removing a tranny isn't that tough. If the exhaust goes under it, you'll need to drop the exhaust, if it goes over it (not likely) then you can leave it.

    You'll want to take the driveshafts off first, then remove the transfercase. To drop the transfercase, use a hydraulic floor jack, lift it up under the transfercase, using a 4x4 if you have to extend the reach of the jack. Strap the transfercase to the jack using a tiedown strap, or something similar so it can't fall off the top of the jack, then carefully lower it down.

    Be warned, when you split them apart, you're gonna get ATF puking out of the back of the transmission, and probally some gear lube from the transfercase too.

    After you've got the transfercase down, then carefully slide it off the jack, and onto a creeper or something, so you can roll it out from under the truck.

    Now that the t-case is out of the way, its time to tackle the transmission.

    First, you'll need to jack the tranny up by the pan, and remove the mount the adapter is bolted to, and slide it out of the way, remove the TV cable / kickdown cable (depending on your tranny) any vaccum lines, the shift linkage, any anything else that may be attached to it. We want to drop the tranny, not test the tensile strength of various cables, lol

    Once you've got everything unhooked, then remove the flexplate inspection plate, using a 9/16 socket on an impact gun with an extension, take out the three bolts that hold the torque converter to the transmission (my bolts there were 15mm for some reason, but most I've seen have been 9/16) If you don't have an impact gun, you'll need to find some way to hold the flexplate so the engine won't rotate, while you remove them with a breaker bar.

    Next up will be the bellhousing bolts. They are 9/16s most of the time, and usually come out fairly easily. There are two you must get from the top of the engine, and two to come out from either side. The top and driver's side are easy to get at, so save them for last, so you don't kill something while trying to get the two from the passenger side out :) If you've got manifolds, it isn't quite so bad, but with headers, its a real pain in the butt.

    After you've got all of those bolts out, and you are 100% sure that everything is dissconnected from the transmission, find yourself an axle stand, with a peice of 2x4 to set up under the oil pan. When you drop the transmission out and back, the back of the engine will want to drop, and if you let it, you'll wreck your engine mounts. After you have got the stand setup, then very carefully pull the transmission back, off the pins on the bellhousing, and lower it down. Take your time, and never put yourself into a postion that the transmission could fall on you. While you are letting it down, watch to make sure that you notice the TV cable tightening up cause you forgot to unhook it, before you wreck it! lol :D

    Once the tranny is down, again, transfer it over to a creeper, and roll it out from under the truck, and voila, you have your tranny out. Installation is the reverse of removal, and typicall a bit more challenging, as you gotta line stuff up for bolting things together, and sometimes that can be a real pain in the butt!

    Good luck, and if in doubt, ask questions!

    EDIT:

    Just a note I remembered for re-installation:

    Before you try and jack the transmission up, you need to make sure that you have the torque converter seated all the way onto the input shaft. Usually there are three "steps" to get it all the way on. To make it go the next step, you gotta rotate, and push at the same time. You'll know you are all the way in if you have got a good 1/2" between the flexplate and the torque converter with the bellhousing all the way up against the back of the engine.

    If you force it on by tightening the bolts, you risk breaking your flexplate, torque converter, and more lethally, your transmission's hydraulic pump housing.
     
  3. trailblazr81

    trailblazr81 1/2 ton status

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    What year?
    What tranny?
    What T-Case?

    In my '81 it was a PITA!!! TH350 and NP208. Trying to do tranny with T-case. Just tranny you can get away with a floor jack but if your doing tranny and t-case I highly recomend getting a tranny attachment for yer floor jack. That way you can chain down the heavy, awkward t-case. Still I recomend bribing a buddy or 2 to help ya.

    I dont look forward to doing the same on my 73. But when that day comes Im just gonna go to a 700R-4.
     
  4. divorced

    divorced 3/4 ton status

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    I've always done this with a body lift, but it may work without one also: To help get the transmission back on the engine I cut 2 pieces of all-thread about 2 1/2" to 3" long and threaded them into the lower left and lower right holes in the engine block. Then just get one of the two all-threads started through a transmission hole and install a nut on the end of the all-thread. This will hold one side where it needs to be while you line up the other side, and start a nut over there. After both all-threads are through the transmission you can tighten the nuts to pull the transmission toward the block, using the jack to adjust the height/angle as needed. After it is against the block you can install the remaining 4 transmission bolts. Then use a double nut to remove the 2 all-threads if they don't come out easy, and replace them with the remaining 2 transmission bolts.
     
  5. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Thats a good idea Divorced!

    Wish I had thought of that when I was doing the tranny on my 89, lol

    I fiddled for quite a while till I got it back on...
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    good idea..

    I use headless bolts as guide pins while putting in a tranny too,it makes it easier when your alone..its highly reccomended on manual trannys too,it keeps the tranny aligned with the clutch disc,and also prevents the weight of the tranny from bending the splined hub in the disc(it doesn't take much to do it too :doah: )--that will lead to chattering and might make the clutch "drag",and not release all the way..not many of us can bench press a SM465 and stab it right in on the first try,and not let it "hang" while trying to get a bolt started.. :rolleyes: :crazy:
     
  7. seschev3

    seschev3 1/2 ton status

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    Just an addition. Use a box end wrench and a bolt to hold the torque converter in when removing. Having it fall out can be costly and painful. A drip pan is very usefull as well unless you are missing a spot on your already stained driveway. Seals are also very important an cheap. throw in a new seal between the tcase and tranny. And you might want to block the wheels before you release the driveshafts.
     
  8. elijah j langworthy

    elijah j langworthy Newbie

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    Awsome thread. I have to install a th400 and my doubler (203 205) in tomorrow. I couldnt find a doubler install thread but this is close enough. I do have one question though. the bars from the engine to tranny where never installed on this blazer i inherited. How important are they? Thanks
     
  9. Blue85

    Blue85 Troll Premium Member

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    An actual transmission jack is much safer than balancing gear boxes on a floor jack and saves time on reassembly. The key is the angle adjustment so you can just turn knobs to get things lined up. If you don't want to rent one, you can get one of these for about $50. They're OK.

    [​IMG]

    Park facing East and do the bellhousing bolts as the sun starts to set. :cool1:
     
  10. diesel4me

    diesel4me 1 ton status Premium Member

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    I have one of those adapters for the floor jack,and have removed a few transmissions with the transfer case still attached, by putting the jack plate under the transmission crossmember after removing all but two of its bottom bolts to the frame rail,and using the chain around it,plus a bolt or two through the member and jack plate (there happened to be holes in the crossmember in the right spot!)--then pull the transmission away and carefully lower it after removing the last two member to frame bolts..

    Be careful because the transfer case may either want to drop,or tilt up towards the floor of the truck,as its weight may not be close to what the transmission weighs,and the two may not be well balanced on the jack plate..a long 2x6 under the jack plate may help,and its important to use the chains and or ratchet straps to secure both well to the jack plate..

    I did a SM465 manual with a NP-205 t-case that way twice in my '72 K5 when the "new" rebuilt clutch decided to fail,I went through 2 12" three fingered pressure plates,before putting a diaphram type back in on my third attempt..I was ready to have the TH350 rebuilt and stick it back in,but after a week "converting" it to manual,installing pedals,etc--I really hated to have to go back..

    Despite the weight of both being extreme,I managed to roll the assemble back far enough to install the clutch (it had an open bottom bell housing,cast iron,so at least that did not have to be removed!)--then I had to use me legs to push the trans & t-case back into position--the headless longer bolts in the bellhousing top holes were a big help in getting it aligned,it went in fairly easy..one pebble under your jack's wheels can make it darn near impossible though,so sweep the area clean first!..
     
    rhinoblzr likes this.
  11. rhinoblzr

    rhinoblzr Registered Member Premium Member

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    Thanks, I went the the freight and got their biggest tranny jack. Didn't feel like having my eyeballs fly out lol. Is it easier to disconnect the t case first? Or take down as one unit? Thanks
     
  12. mechted

    mechted 1 ton status Premium Member

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    If its a lightweight aluminum transfer case like a np208 or np241, they are easy enough to pull off by hand and lower down. Then the transmission is much smaller and easier to move around, especially with a trans jack. If its a heavy cast iron np203 or np205, take it up and down as a single unit. The balance point tends to be fairly close to the cross member mount. In either case, drain all the fluid you can from both the trans and the case before you drop them.
     
  13. rhinoblzr

    rhinoblzr Registered Member Premium Member

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    Right on thanks. Its a 203 205 doubler so i'll take it down together. Now i just need a driveshaft shop in ventura and im on the trail.:saweet:
     
  14. rhinoblzr

    rhinoblzr Registered Member Premium Member

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    Sorry im new but does anybody know how this goes together? Trans is threaded and doubler is not or stripped.

    [​IMG]
     

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