Saturday, November 24, 2012

Transmission rebuild and reinstallation

Once it got too cold in September to do much more body work (too cold to spray epoxy) I shifted gears to the engine.  My goal and projects for the winter are to get the engine fired up for the first time ever...and actually have a running car.

I had no idea as to the condition of the C4 that came mated to the blown 289 that came with the car, but I had it rebuilt figuring it was probably pretty tired.  I took it to a local old school transmission rebuilder who has been rebuilding transmissions before the C4 ever existed--L&S Transmission in Delton, MI.  Needless to say, Lane has rebuilt a lot of C4's.  The transmission ended up being shot inside as Lane found some broken gears so my gamble to rebuild was a wise one.  He added a shift kit and new torque converter from Precision of New Hampton (fellow Iowa boys) with a stall of 400-500 over stock.

Since I had put the engine and transmission back in the car to move the car from Iowa to Michigan, my wonderful wife, Rosemary, helped me with the removal.  Though she tries to avoid anything Mustang she did admit it was kind of fun pulling the engine out and it didn't take us more than 30 minutes.  Which is probably why it was fun for her.

This is the transmission as I got it back from the rebuilder.

New torque converter from Precision of New Hampton (Iowa).

The transmission was cleaned with paint prep wax and grease remover (even though it was cleaned at the rebuilder's) and primed with engine primer.

Then repainted with Rebuilder's Aluminum finish to give it a fresh new aluminum look.

Before putting it back in I took advantage of its absence and cleaned and prepped the undercarriage.  This is the original Ford Red Oxide on the undercarriage in NEAR PERFECT condition!  To preserve this rare bit of history, I only spot primed areas where I sanded through or had bare metal with Eastwood's Rust Encapsulator (Red), which ended up being a very close match for Ford Red Oxide.

Next spacer plate is attached to the back of the engine via mounting pegs and then the flexplate is bolted to the crank.  DO NOT FORGET TO INSTALL THE SPACER PLATE FIRST or you will be sorry!  I sanded my spacer plate down well with DA to remove rust then treated it with zinc phosphate to give it a nice new looking finish and some rust protection.  Even though they appear to be symmetrical, the holes on the flexplate only line up to the crank in a single orientation, so there is only one correct way to install the flexplate.  Install the retainer ring next and rotate until the holes line up.  Place high temp oil-resistant thread sealant on the bolts and tighten down to spec using alternating tightening sequence.  A buddy will need to keep the crank from moving by placing a socket and breaker bar over the front crank bolt.

Install the torque converter.  Gently push it into place and slowly rotate while still pushing.  It will seat about 4 times.  For the final seat it will seat in completely.  Rotate several more times to make sure it is completely on, otherwise you can damage the pump if you try to install it and it's not completely seated.  Place a straight edge across the bellhousing and measure the distance from the edge of this to the snout in the middle of the TC.  It should be 1/8 of an inch. 

Orient the drain plugs so they are straight up and down, then place a 7/16" deep well socket over the bottom drain plug as an alignment aid when mating to the engine.  Orient the flexplate on the engine block so the holes for the drain plugs are straight up and down.  With the engine block hanging from the hoist by a leveler, level the engine so it is exactly at the same pitch of the transmission then push it together.  The socket should come right through the hole in the flexplate to know the alignment is correct.  The pegs in the engine block should fully seat in their respective bosses in the transmission bellhousing.  DO NOT PULL TRANSMISSION AND ENGINE TOGETHER BY TIGHTENING BELLHOUSING BOLTS.  They should come together smoothly.  Bolt bellhousing to the block.  The studs on the converter should also be sticking through the holes of the flexplate.  Rotate the crank with a breaker bar to rotate studs to the bottom so they can be accessed to install nuts.  Tighten all nuts down to torque.

The engine and transmission mated together.

Reinstallation (with starter bolted on)

Undercarriage.  I have a body plug kit and installed new plugs.

With transmission crossmember reinstalled and torqued to spec.


  1. Enjoying the blog. That engine, transmission combo is looking really good. One step closer to a driving car. Keep moving forward (ha)!

  2. welcome to my musings, Grant! Thanks for the comments and I must agree the combo does look rather sexy....right now. To me the most painful thing about a restoration is watching everything you once made look brand new deteriorate and look a little worse and worse every year... It's truly bittersweet.

  3. First of all, I'd like to thank you for your wonderful and educational blog. The pictures are so amazing as well. This will serve a great help to anyone who have a car, most especially if they have a car workshop of their own. It can be pricy to buy such equipment and materials. On the other hand, it can be efficient, and can serve as a livelihood when your neighbor sees that you have a workshop and knows a lot about car repairs. Knowing a lot about transmission means that you can be a car mechanic expert.
    Jae Gunderson

    1. Thanks for the very kind words Jae. I am quite ignorant when it comes to transmissions, but I try.