Wednesday, 21 March 2012

Replace Rear Seal in a Volvo 240

The car is a 1990 Volvo 240 DL with ~310,000 km and an AW70 automatic transmission.  The problem is a leaky rear seal in the transmission shaft.  I did this job last week because of three problems:

  1. I leave puddles (about 3-4 Tbsp) of transmission fluid every time I park
  2. I need to constantly top of my transmission fluid, costing $$
  3. The transmission has to work overtime with so little fluid and ends up costing in fuel economy.
There are a few suggested methods (see here and here) but I took a slightly different route outlined below.  But before that, a word about parts.... I spoke with a handful of suppliers and only one could locate the part I needed.  I heard people call it the 'output seal', the 'rear output seal', the 'rear shaft seal', the 'rear transmission seal', and the 'output shaft seal'.  Make sure you get the correct part.  If you have access to a spare car you might be able to pull the seal out and take it to a supplier to get an exact match.  But if you're like me and prefer having all the parts on hand to complete the job, get it before you start.  I ended up ordering the ALTROM Rear Seal 2116020 from Napa, which looks like this:
This looks a bit different than some other seals you'll find on the market (and from the one I took out of the car).  They look like this:

I suppose they perform the same.  Here's the complete parts list:
  • ALTROM Rear Seal no. 2116020 from Napa ($13)
  • Transmission Kit FK-162 from PartSource ($15) *this isn't necessary, but might as well do it*
  • 4L Mobil ATF D/M 598368 from PartSource ($16)
With parts in hand, here's the procedure.  Note that I estimated 3 hours and it took 4-5:

  1. Jack up the car and put it on jackstands.  Do not ride up on ramps as the wheels must be free to rotate
  2. Shift car into N.
  3. Drain transmission fluid.  It doesn't have to be done now but it must be done before Step 12
  4. Mark/score the rear flange and remove the 4 driveshaft bolts from the flange (near rear wheels).  You may need to rotate the driveshaft to get at all 4 bolts, and the flange may need a whack with a rubber mallet to come free.  Impact wrench on the bolt heat and hand wrench on the nut.  
  5. Mark/score the front flange and remove the 4 driveshaft bolts from the flange (near tailshaft housing).  May also need a rubber mallet.  (Note: some guides advocate removing the tailshaft housing.  Not a bad idea, but much more work and not entirely necessary if you have a socket the exact diameter of the new seal)
  6. Remove the 4 bolts on the crossmember bracket and prepare the lower the entire driveshaft to the floor for later usage.  You will need to replace one or two of the bracket bolts to keep some sheathing from falling down. You should now see the centre bolt inside the front flange.  
  7. Shift the car into Park.
  8. Remove the centre bolt from the flange.  Impact wrench ok.
  9. Pull off the flange and remove the rear seal.  I used a flathead screwdriver and broke the seal while getting it out.  No matter, it was leaking anyway.
  10. If you have a socket in the correct size, gently tap the new seal into the housing.  Be careful not to press in too far.  If you don't have a socket this size, borrow one!  It's way easier.  If you must, remove the entire tailshaft housing and press the new bushing in.
  11. You can now reverse steps 4-11 to reinstall the driveshaft assembly.  Make sure to shift back to Neutral after installing the centre transmission bolt.  Also make sure not to overtighten if using impact wrenches.
  12. The remaining steps are to change the transmission filter and gasket.  It's not necessary but is probably a good idea if you've been running low on transmission fluid.  If you didn't do so before, drain transmission fluid.  
  13. Pull off the 14 bolts on the transmission pan.  Remove the pan gasket from the pan and clean thoroughly (esp. if it was an old cork gasket.  The new kit comes with a silicone version).
  14. Pull off the 5 bolts for the transmission filter.  Have a look at the new filter to make sure you're loosening the right bolts.  You may need to pull off a steel line or two (they're just tension fitted)
  15. With the pan and filter out of the way, spray the entire assembly with brake clean.  Get all the fluid out of there so it's not dripping on you when you replace the filter and pan.
  16. Clean the pan and magnet in a parts washer or with brake clean.  Get all the grime out of there.  
  17. Bolt the new filter (with gasket).  Use torque settings if you have them.
  18. Replace the pan and pan gasket, and add some RTV to make that gasket stick well.  14 bolts and you're done the hard stuff.
  19. Now, add as much fluid as you removed (possibly more if you were running really low).  I believe it is around 3 L, maybe a bit more.
  20. Start the car in Park and slowly cycle through all gears.  Check for leaks and go grab a beer.


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