Transmission Swap Economics

[ggunder]

With the transmission out I have replaced the rear main seal, replaced the oil pan seal, and replaced the input and output shaft seals on the new 5-speed described above. The flywheel has been resurfaced and is installed/torqued. Next I will assemble the front plate on the transmission with a new gasket. I need to take the yellow speedo pinion gear from the old 4-speed and install it on the the 5-speed pinion carrier from the "parts" transmission mentioned above (being mindful of the difference between the earlier and later 5-speeds in terms of pinion carrier position). The problem is that the new 5-speed transmission does not have the worm drive on the internal shaft to make the speedo turn! Have I just bought another problem? The new transmission seems to spin and shift just fine.

Ach!

Gary

[olzed]

Before you go dismantling the speedo drive, you may be able to just replace the whole unit. I think all the speedo drives are interchangable. But then I may be wrong. I have changed only a few.

.

[Zed Head]

I think that he means that he can't see the gear inside the transmission, or when he inserts the speedo drive asembly it doesn't turn.

The 5 speed hold down slot is on the opposite side for the later 5 speeds. You could actually grind a new hold down slot in the drive assembly and get it to work. Put it in with the slot on the opposite side and see if it catches and turns. It would be odd for the gear to be missing entirely.

[ggunder]

Well I believe this is odd. The drive gear for the speedometer on the transmission shaft is missing! Below is a drive gear from the first (wide ratio) 5-speed that was taken apart, so I have some idea what it looks like. I guess I am looking at this one coming apart too if the drive gears interchange from wide ratio to close ration 5-speeds. I could just spring for another 5-speed on Craigslist, but they are starting to take over the garage! Who would have thought it would be missing?

[ggunder]

To wrap this up on a good note, I took the close-ratio 5-speed (trans #2) to the shop recommended above who installed the missing speedo worm drive (donated by 5-speed #1). They also replaced the gaskets and seals along with a complete bearing set for $450. The car is now all assembled and I am really enjoying that 5th gear! At nearly 80 mph the engine is only turning about 3,000 rpm. All the gaskets and seals have held up fine including the new main seal and oil pan seal.

No responses on Craigslist to the used 4-speed or 5-speed in parts. Any ideas for recycling these?

Thanks for the help from everybody! Watch out for a multi-colored '72 on Highway 50!

[Zed Head]

That is an odd thing to happen (the speedo drive gear disappearing) but good that you had all of the right parts and found a good shop. You ended up with the better 5 speed anyway. I'm guessing you went to the shop that Powderkeg recommended? $450 doesn't seem too bad. With synchros, for a "full" rebuild, you'd probably have been at ~$750 (assuming $50 per synchro and a little more labor). Better than $1500. But if you didn't need the synchros, then bearings and seals is the way to go.

I don't know how much you're asking for the transmissions but the front case (bellhousing) alone is probably worth $50 each over on Hybridz. It's used to convert a 240SX or 300ZX transmission for use with an L series engine. You need to contribute a small sum to the site before you can sell parts, but if you're a member over there, it's worth a thought.

[ggunder]

Thanks for the tip Zed. My craigslist pricing is $25 for the 4-speed and $50 for the 5-speed and nobody is responding. I need to clear some stuff out so my wife does not start "rearranging" the garage!

The shop I used is the one Powderkeg recommended, so that was really helpful compared to AAMCO.