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 Post subject: Transmission Help
PostPosted: Sat Oct 25, 2008 10:58 am 
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Joined: Mon Sep 08, 2008 11:40 am
Posts: 198
Location: Jamestown, RI
I am doing some final restoration work on my 1970 240Z and have been considering swapping out the original 4-Speed Tranny for a 1973 240Z 4-Speed I have because I've heard that the 73' is a superior unit. I have 4 questions: (1) what are the differences in the two units - is the 73' a superior tranny and why? and (2), the 73' tranny is marked only with an "L4" and bellhouse # 7609776 and it appears to have a shift stick mount about 2.5" to 3" further back than the original 70' tranny even though the overall length of the 2 trannys are identical.

Question (3) - I've been told that the later model transmissions of the 240Z models just "bolt right up" but would like to have this verified and have a solution or answer for the discrepancy in the 2.5" to 3" rearward placement of the shift stick. Question (4) - there is an extra electrical wire lead on the 73' unit, what's this for? Thanks for any help.


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 Post subject:
PostPosted: Sat Oct 25, 2008 7:29 pm 
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Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
I will have to dig out my manuals and quote them directly for accuracy, but from what I recall there were complaints about the shifter on the earlier transmissions. That was, in fact, the final death blow to my 1970 car (#2807) which caused me to finally let it go. (It stuck in 3rd gear and nothing I could do would make it come out). As you know, I now have that same car back and a ZX 5spd was one of the first improvements made on the car.

BE ADVISED, however, that any replacement gearbox you swap into the '70 car will require you to butcher up the plastic/fiberglass transmission tunnel cover to allow for the stick to come up somewhere other than where the original did. I have seen some very neat jobs done on this, but then there were others......

The plastic is easy enough to carve up, but then what do you do with the hole for the original stick position?

Some owners have opted to install the plastic transmission cover for the same year as the transmission. It fits, it looks nice ~ it just isn't "70".

The manuals will tell us what the spare wire is for if someone else doesn't answer first.

Too tired and distracted to look it up tonight.
frank


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 Post subject:
PostPosted: Mon Oct 27, 2008 12:51 pm 
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Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Regret this took so long ~ I'm juggling housecats here lately and this is the first break I've had.

According to HAYNES AUTOMOTIVE REPAIR MANUAL for 240 and 260Zs, the second wire on your transmission is for a neutral indicator light (altho I can't recall ever sitting in a Z car which had such a light evident on the dash or console. Maybe they were for British or Aussie or Japanese cars? Or maybe they were for U.S. but I just never noticed one). The only external wires or cables listed off the gearboxes are for reverse lamp, neutral indicator, and speedometer cable. The neutral switch itself is on top of the transmission, only a few inches forward of the gearshift on the F4W71B gearbox.

The reference lists THREE manual gearboxes and an automatic:

Type F4W71A 4 fwd spd & reverse, 240Z early
Type F4W71B 4 fwd spd & reverse, 240Z later and 260Z early
Type FS5C71A 5 fwd spd & reverse, 260 later
Type 3N71B 3 fwd spd & reverse, automatic (all)

The reference lists specifications for each unit (including weight and gear ratios) if you're interested, but it's too tedious to list here unless you need it.

Ask Tom Wasney, Paul Mackin, AirJockie, Dan Linquist or Bryan Little if the swaps are bolt-in or not. I would ASSUME (oh, oh!) that they are, since the Japanese are smart enough to save themselves unnecessary retooling costs as they improved their cars, but I've not had to do one myself and these guys have done several apiece.

Odd that your gearbox only shows that designation. I'm confident there is a full designator cast into it somewhere you haven't found yet.

Frank

(By the way ~ if both boxes are out of the car, take time to pull the drain plugs on each and clean off the nifty little magnet they installed there. These collect any metal filings and can give you an indication of the general condition of the 'box).


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 Post subject:
PostPosted: Tue Oct 28, 2008 5:12 pm 
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Joined: Wed Jul 23, 2008 2:38 pm
Posts: 3411
Location: rhode island
To what was said, there was a 5-speed for the 240, european only, then after some years of having the 5-speed that was wide ratio, they came out with a close ratio tranni. in 1980, the 80 had a taller 5th, the 81-83 n/a was the same with a little shorter 5th, but 80-83 is what you want, good luck finding an 80. I have an 81 that needs new countershaft bearings, but might as well replace them all, and a seal kit. Even in it's condition as is, I wouldn't let it go for less than $200, if some think I'm crazy, well, we'll see. As far as the 4-speed, I've heard of the tranni's getting better through the years, just not shure of the details. I have a 4-speed from a 76 out and about, then a 75 still within. Also a 79 5-speed, but like I said, it's wide ratio.


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 Post subject:
PostPosted: Tue Oct 28, 2008 6:08 pm 
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Joined: Wed Apr 09, 2008 5:53 pm
Posts: 14778
Location: CT
Right again Paul!

The main difference btwn the early and later 4spd boxes on the 240s was the shifter mechanism. The early model (F4W71A) had what appears to be a "cup"-like receptacle at the bottom of the shifter. The improved model (F4W71B) had a twin-fork arrangement which resembled a wall plug laid upright, with the prongs facing upward.

The gear ratios changed as well. First quotes were for the early (71A) box, the second numbers are the improved (71B) box:

1st gear: 3.549:1 ~ 3.592:1
2nd gear: 2.197:1 ~ 2.246:1
3rd gear: 1.420:1 ~ 1.415:1
4th gear: 1:1 ~ 1:1
Rev gear: 3.164:1 ~ 3.657:1

Frank


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