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Re: Another transmission ID.

Posted: 23 Jul 2018 13:53
by iceD
Will a L series bell housing fit a napZ transmission

Re: Another transmission ID.

Posted: 23 Jul 2018 15:43
by Byron510
In short - yes IF the L series bell housing was a 71B 5sp - maybe a 4 speed (not sure if someone can collaborate).
It is important to check the shims on the ends of the main bearing shaft, this is important as incorrect shimming will lead to the transmission not wanting to stay in gear - so it needs to be checked.

I'm no transmission guru, but this is what I do know to date.

Byron

Re: Another transmission ID.

Posted: 24 Jul 2018 05:16
by Three B's Racing
Byron510 wrote:
23 Jul 2018 15:43
In short - yes IF the L series bell housing was a 71B 5sp - maybe a 4 speed (not sure if someone can collaborate).
It is important to check the shims on the ends of the main bearing shaft, this is important as incorrect shimming will lead to the transmission not wanting to stay in gear - so it needs to be checked.

I'm no transmission guru, but this is what I do know to date.

Byron
Byron is correct, the counter shafts bearing needs to be measured and properly shimmed.
Counter 2.png
Counter 2.png (109.09 KiB) Viewed 228 times

Re: Another transmission ID.

Posted: 25 Jul 2018 19:16
by datzenmike
iceD wrote:
23 Jul 2018 13:53
Will a L series bell housing fit a napZ transmission
It's actually a front case as it covers all the gears 1 through 4 and not just the clutch. Yes 4 or 5 speed cases will bolt on with two or three possible exceptions you will need to check.


1/ Some older 4 speeds have the reverse switch about an inch behind where all other 4 and 5 speeds are. It's rare but could happen.

2/ If the NAPS 5 speed is from a '75 truck it will have a 62mm counter bearing. All 71Bs made before this have a 56mm bearing so the 62mm bearing will obviously not fit the 56mm hole in the front case. Easiest thing to do is pull the 62mm bearing off and hammer a 56mm bearing on. A new bearing as they are failure prone and why they were increased to 62mm.

3/ On the '85 and up 71B the first/second shift rod may have been increased from 14mm to 16mm. Again this won't poke out through the front of the earlier front case. Just drill it out.

Re: Another transmission ID.

Posted: 29 Jul 2018 18:06
by RMS
got a guy needing trany work on his 81 diesel 720 2wd, will bits from one of my 720 z24 gas pot trans work ?

Re: Another transmission ID.

Posted: 31 Jul 2018 06:28
by Byron510
RMS wrote:
29 Jul 2018 18:06
got a guy needing trany work on his 81 diesel 720 2wd, will bits from one of my 720 z24 gas pot trans work ?
Eh Robyn, I was once told that the diesels have a larger input shaft spline. I’ve never had the chance to verify, maybe you could if it’s going through your hands.

Regarding interchangeability, I don’t have that information. But it would be very interesting to know what the gear set is.

Byron

Re: Another transmission ID.

Posted: 31 Jul 2018 17:07
by datzenmike
I have an '85 diesel in pieces and the input splines are the same as all Nissan input splines. Only the front case is different with the starter on the driver''s side and the bolt pattern. Actually the diesel front case can fit the Roadster R16 and U20.
RMS wrote:
29 Jul 2018 18:06
got a guy needing trany work on his 81 diesel 720 2wd, will bits from one of my 720 z24 gas pot trans work ?
.... yes. The diesel used a wide ratio gear set, the Z24 depends, as, wide and mid ratio sets were used. If the Z24 transmission is in good order swap the diesel front case onto it and drive away. If it's from an '85 swap the diesel front counter gear bearing onto it. Possibly the first/second shift rod hole will need to be drilled out to 16mm from 14mm. Use the diesel front cover plate over the bearings.