The previous owner of my Mighty Z-car obviously loved it because there was evidence of prior rust repair with welding new metal to the body, but the Midwest winters were more than the original undercoating and proper care could handle. I put the Mighty Z-car on stands I decided to finish frame rail replacement and my much needed transmission rebuild projects at once. Wish me luck.

I jacked up the Mighty Z-car with a 3.5 ton jack and supported it with 6-ton jackstands in the back (at the jacking points in the owners manual) and in the front on the frame rail between the lower control arm and the brake line. Although not pictured here, before I started working underneath my Z, I placed additional jackstands under the front and rear cross-members and I placed wooden blocks at each jackstand for support if the car slipped off the jackstands (however unlikely).

The drivers side frame rail. I previously treated it with Rustoleum spray paint after using a shop-vac to remove the rust bits from inside.

The passengers side is not in any better shape.

Another shot of the passengers side once I got done relocating the gas/brake lines about 3 to 5 inches from the action (I also drained the gas tank - just in case). More rust, even a hole back towards the rear of the frame rail, worse than the drivers side.

Here is a shot of the passengers side frame rail from Baddogparts.com. Its a pretty good fit, but there is not much of the original rail to weld it to...right now i drilled two bolts through the floor to hold it in place during welding.

The replacement frame rail from Baddogparts.com fit really well over the remnants of the drivers side frame rail when I was done grinding. I put 2 bolts through the floor to hold it in place while welding.

Here is a shot of the drivers and passengers replacement rails mounted but not welded.

After having both replacement frame rails from Baddogparts.com welded on by PMJ Welding, I applied POR15 and some fiberglass where the metal was too thin or rusted to weld. After that, three coats of rustoleum primer. And finally two coats of 3M Rubberized Undercoating (this stuff was a freaking mess, like tar in a spray can).

I had to remove the interior because I did not want the carpets to catch on fire and the seats to melt when I started welding the replacement frame rails on. I expected to see the floorboards swiss-cheesed with rust, but to my amazement and disbelief, they appeared solid with only minor surface rust (which I am sure may be the tip of the iceberg).

Well I was right - the tip of the iceberg. While the frame rails were being welded on, the sound-deadning on the floors smoldered and caught fire in places. I chipped off the remaining material and found a few minor holes in the drivers side.

And a few more in the passengers side.

To address the rusted floors, I was considering floor pan replacement but there were only a couple holes and the rest of the floors seemed solid. So I used 2 coats of POR15 and fiberglass then applied two more coats of rustoleum primer. I think it turned out pretty good.

So thats the rust repair, on to the transmission!

While I have the floor console off, I am going to complete the brass shifter bushing upgrade found on Blues Tech Tip page to reduce play caused by the 28-year old worn plastic bushings.

Now the transmission is out. The factory service manual was great, just follow the directions.

The 5-speed was not very heavy (thanks zcar.com) and I lifted it from the engine and transmission tunnel onto the ground. I will start cleaning it up and tearing it down for the rebuild.

I finally got the front and rear housing off the transmission. It took lots of penetrating oil and hammering, also going along the seams with a screwdriver.

Found the culprit! Someone on zcar.com said that there is a nut at the back of the transmission that will work itself loose causing gears to come out of place. This is excactly what happened! The nut (me holding it, not me) is at the back of the transmission and when it slipped off I lost 5th and R, which are also located at the back of the transmission. 1 through 4 are fine!

Snap ring and thrust bearing. How the hell do I get this back together properly?

3rd and 4th gear assembly. How do they come off?!

I am Aaron's failed attempt at a transmission rebuild. TECHNICHALLY I was susccessful in fixing 5th and R, however when I put the transmission back in 1,2,3, and 4 didnt work. So I pulled it again (Im getting good - 1 1/2 hours for removal and 1 1/2 hours for re-installation), loaded it the back of my truck, and headed over to Eastern Transmission where I explained to Bill that this was a do-it-yourself project and he was happy to spend time with me showing me where I went wrong.

After getting the transmission back and a good explanation from Bill, I re-assembled (correclty) the rods and shift forks. This is a picture of the transmission on the bench.

Shifting forks aligned!

Transmission bolted into place! The red is high-temp silicone gasket sealer.

The fluid I used at first was the Valvoline. My transmission was really noisy so I redrained it and filled it up again with Red Line MTL (thanks again Blue!). It was less noisy.

To fill the transmission I ran a hose into the transmission and up through the engine compartment to a funnel ballanced on the heater hoses. Filled it up until there was minor overflowing, then capped it off (used almost 2 quarts as per my FSM)!

Because the transmission is still noisy (although it seems to work well) I am going to try to source a good replacement. The testdrive down the beach after my Mighty Z-car was on jackstands for over two months was a blast!

I sourced a new transmission from a 79-82 turbo Z. It seemed to be in pretty good shape with the exception of the breather vent that was epoxied over. I just cleaned out the epoxy and replaced it with the breather from my original transmission.

Dude, wheres my transmission? Wheres your transmission, Dude?

The original trnasmission on the left, the "new" one is on the right. The installation went smoothly although I am replacing my bushings with a urethane master set. I did bench test the transmission prior to installing it and I tested the transmission once it was in my Z by giving a little gas in every gear to make sure the propeller drive shaft (i.e. wheels) turned. They did.

The transmission saga continues...I was on my way to another autocross in Homestead at 530 am, went to put it int o 5th and no dice. I pulled off to the side of the road and couldnt get it into R either. I figured that the nut on my main input shaft backed off again. I figured wrong...

Well, the transmission is out of the Mighty Z again and again and again and again...

Unfortunately upon closer inspection a couple chipped teeth on the counter gear and the 5th gear may be the problem why I cant shift into 5th and R all of the time.

Screw it, I am not going to take a SECOND transmission apart and screw it up. Besides, you dont need 5th for highway driving (my Z cruzes comfortably at 80 at about 3500 rpms - just like the 4 speeds. And you dont REALLY need R as long as you are SMART about where you park.

The Transmission back in the Z using my computer-friends 3-ton jack. I could bench-press it back in, but it is so much easier using the jack to line the main shaft through the clutch pressure plate. I refilled with Redline MTL through the R-light because the fill plug was S-T-U-C-K stuck.

I will probably take my original 5-speed to a transmission shop and have them professionally rebuild/upgraded it using stiffer sincro springs, new bearings, etc. May as well bite the bullet and have a pro look at it rather than me having to pull it every 4 or 5 months only to have it break again or not work properly.