Transmission Inspection

[ggunder]

I just bought a very inexpensive early (1977) 280Z 5-speed transmission to replace the 4-speed on my '72 240Z. It may be in good shape as it was pulled from a running vehicle many years ago to be used as a spare for racing. It was stored and never used. The input shaft where the clutch and pilot bearing would be mounted is rusty and a little bit pitted. I got the fill and drain plugs off and there was only some black greasy material inside around the drain plug hole. The magnet on the drain plug did not have any metal, so that was a good sign. I could not see any rust inside, but a few drops of water did come out with the greasy goo.

Short of a complete rebuild, which is expensive and maybe not required, is there a way of cleaning it and inspecting it? If the seals could be replaced at the same time that would be great. What should I do about the input shaft rust? I am not set up to do this complicated of a project, so any suggestions on transmission shops in the general Sacramento or even east bay areas would be great.

Thanks for your input. This is a really fun car to work on.

[bluezcrazy]

Hey ggunder,

Sounds like you found a 5 speed in the shape I found mine. I would recomend you at least do the same to prep for installation, not as extensive or expensive as a rebuild. This way you will know it won't leak short after installation due to dried/hardened seals.

Due to rust on the input shaft I cleaned it using emery cloth and spent some time to get it smooth. You don't have to get the pits completely gone, but you do want it as smooth as possible. Next I replaced the tail shaft seal, and removed the front cover inside the bell housing to replace the input shaft seal and front cover gasket. Lastly I put new gear oil in the trans, and changed it again after driving the car 50 miles just to make sure the water/debris would get out of there. Be sure and inspect your throwout bearing, clutch, and pilot bearing while you have it apart.

Hope that helps, enjoy the 5 speed. It feels good having that extra gear.

Bryce

[idoxlr8]

I'm going through the same process with my 260. The original 4 speed is in fine condition but I'm replacing all the seals while it's out of the car.

Any hints on getting the front case cover off? Mine is very stuck and don't want to beat on it too hard. Access is a real issue to get any leverage on the thing.

Thanks

Dean

[Zed Head]

I've taken a couple of front covers off recently and found that a heat gun or torch on the cover to loosen the gasket and any sealer helped. Then I used a piece of wood through the clutch fork hole, and a hammer, on the base of the pivot ball to break it loose. You can also use wood to build a fulcrum at the hole and your choice of lever to pry up on the back of the pivot ball. I used the wood to avoid chipping or breaking the case or pivot ball.

The heat made a difference, plus some PB Blaster around the edge of the cover. It will soak in to the gasket and soften it up. I would heat it up, spray some Liquid Wrench, PB Blaster or Aerokroil around the edge, let it soak, pop the back of the pivot ball a few times, then see if it will lever off. I had two that were stuck really tight.

[bluezcrazy]

Zed Head's process of removal is probably better, but.... I believe I worked it off with a prybar after double checking that I had all the bolts removed. Has to be a longer one to work.

Bryce

[idoxlr8]

I'll try the heat and PB blaster.

Thanks guy's.

Dean

[ggunder]

I will head out to the garage here shortly and let the disassembly begin. Thanks for the pointers on getting things undone. I just put the rear brakes together this past weekend, so I want to enjoy driving it while I get the 5-speed prepped to replace the 4-speed. Again, thanks for the input on this!

[tlorber]

Make sure you shake the input shaft, output shaft (and counter shaft if you open it up) in order to see if the bearing races are still tight. If not, they will eventually disintegrate, shedding pieces into the tranny and allowing more slop.

[Zed Head]

Just found this post over on zcar.com - http://www.zcar.com/84-89_tech_discussion_forum/fs5w71c_front_seal_cover_removal_897268.msg2703340.html#msg2703340

He took the pivot bolt out and ran a longer bolt in to bottom out on the case and push the cover off. Probably why one of mine leaked, someone probably did this and didn't reseal the threads when they put it back together.

Edited February 9, 2012 by Zed Head

[ggunder]

Thanks Zed Head, removing the pivot bolt was easy with a 18 mm deep socket. A spare 10 mm 1.50X50 mm long bolt was long enough to bottom out and easily boost the front plate loose. I had been soaking it all weekend and tried a wonderbar with no results. I was concerned about breaking the aluminum housing, so this approach was much better. Thanks again!

[idoxlr8]

Mine responded nicely with a hard rap on the clutch fork pivot ball. That bit of extra leverage made all the difference.

Thanks for the hints all.

Dean

[ggunder]

The rust on the input shaft pilot bushing area is cleaning up pretty well. Any idea what the shim on the counter-rotating shaft is for? It kind of came off with the front cover. Should I just put it back when reassembling the front cover?

Thanks,

Gary