260Z 5 Speed Transmission

ZedzDead

Club Member
Currently living in Hampshire but moving to North Yorkshire hopefully in the near future.

Any recommendations for someone in either area that can R&R and repair (UK 5 speed 260 ) trans with poor synchro between 1st to 2nd gears ?

Tried contacting Z Farm by phone and email and receive no response. I will contact Fourways again but they said a while back they use to outsource but no longer have the contact.

Thanks in advance
 

status

Well-Known Forum User
Local gearbox repairers should be able to do it
one in Walthamstow east London that can do it
 

Farmer42

Club Member
I thought I read somewhere that the synchros are now unobtanium which is why people are switching to S14 boxes. I have the same issue with my 5 speed box but as long as I'm careful it doesn't crunch much. If they can be repaired I might be interested to know where to get the bits.
 

Albrecht

Well-Known Forum User
I thought I read somewhere that the synchros are now unobtanium which is why people are switching to S14 boxes.

Yes. Original UK market FS5C71-A and FS5C71-B gearboxes had steel (Porsche/Servo patent) synchros which are hard to find these days. That's the problem. People Google the question of transmission parts and come up with USA-biased answers, but the USA & Canada market got FS4W71-A, FS4W71-B and - later - FS5W71-B gearboxes with bronze/brass (Warner patent) synchros which are still readily available, which leads them to think a gearbox rebuild is viable and relatively easy. Not so if you want to do it with the original type synchros.

It is possible to switch *some* of the Servo steel synchros for Warner bronze/brass equivalents, but this usually requires the gearbox rebuilder to, ahem, think outside the box. It also usually means a full strip-down and rebuild, which costs time and money. That's why people were tending to switch to used C-type 'boxes. It killed two birds with one stone. But now that C-type 'boxes are much thinner on the ground and cost more, it is less easy.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
As far as I know the Z Farm are not gearbox experts. Even if they were the parts are not available. The later S14 box is a huge upgrade but they too are hard to find and require significant mods. If speed is not a priority drive to your gearbox. Double de clutch is done up as well as down the 'box just don't blip the throttle but let the gearnox slow down. Lorry drivers used to do it when I was younger.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
I thought I read somewhere that the synchros are now unobtanium which is why people are switching to S14 boxes. I have the same issue with my 5 speed box but as long as I'm careful it doesn't crunch much. If they can be repaired I might be interested to know where to get the bits.
On mine, at junctions or from standstill, I go into second then first, never crunches. But if I try first straight away and fast it doesn’t like it often.

Can’t help thinking there’s a market for someone to 3D scan and machine some steel synchros!
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
And what's more only 3 gears so the ratios were wide ha ha. Times were hard back then, windscreen washers and heaters were extras, so don't moan on here about weak synchros.

Sorry I've just been watching 'King of Queens' for the first time.
 
Last edited:

Rob Gaskin

Treasurer
Staff member
Site Administrator
On mine, at junctions or from standstill, I go into second then first, never crunches. But if I try first straight away and fast it doesn’t like it often.

Can’t help thinking there’s a market for someone to 3D scan and machine some steel synchros!
Ali, are you sure your clutch isn't 'dragging'?
 

Albrecht

Well-Known Forum User
Can’t help thinking there’s a market for someone to 3D scan and machine some steel synchros!

A few people have done it in the past (pre cheap 3D scanning) and they are expensive to make, have a limited market and still require pretty much a full gearbox strip down and rebuild to fit (£££). You can see why people look for an alternative with Warner type synchros or C-type 'boxes.

Possibly still a little chicken and egg?
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Perhaps experiment with different gearbox oils? Some on here have and might be able to recommend something.

One thing I was told was not to use Molyslip or similar additives as they reduce friction and stop the synchro hub working effectively.
 

Albrecht

Well-Known Forum User
Perhaps experiment with different gearbox oils? Some on here have and might be able to recommend something.

One thing I was told was not to use Molyslip or similar additives as they reduce friction and stop the synchro hub working effectively.

Good point, and the steel (Porsche/Servo patent) synchros have a quite specific requirement for lubrication which was often misunderstood (or ignored) in period because people were tricked into using the data for Warner type synchros.

In my experience SWEPCO 201 is the best choice, but hold onto your hat when looking at the price...


Some people have reported that switching to SWEPCO 201 on their Servo synchro 'box has transformed it. The steel synchros have a built-in 'grab' in their function which some people find slightly disconcerting. One of the main reasons why Nissan used softer feeling brass/bronze synchros in the North American market was because they felt that drivers in that market would not 'get' the sporty and rather mechanical feel of the steel synchro action.

That steel synchro 'grab' is often confused with notchiness and/or worn synchros, but is a built-in dynamic feature.

There are probably some good alternatives to SWEPCO 201 (Kendall NS-MP is a suggested alternative, and that too is an 80W-90 GL-5 hypoid gear oil) so worth looking into.
 

toopy

Club Member
There are probably some good alternatives to SWEPCO 201 (Kendall NS-MP is a suggested alternative, and that too is an 80W-90 GL-5 hypoid gear oil) so worth looking into.
I thought a GL4 oil was the recommended choice for 'our' gearboxes, or is that what you mean by the misunderstood/ignored shpeel from back in the day?
 

Farmer42

Club Member
So I have a JDM car with a 5 speed box and presume I have the steel synchros. I also presume that the stiff, almost binding gear selection is a 'normal' thing for those boxes and may be overcome by putting in the right oil. I have been using GL4 oil which I am now assuming was wrong. Confused.com!!!:conf2:
 
  • Like
Reactions: Huw

Albrecht

Well-Known Forum User
I thought a GL4 oil was the recommended choice for 'our' gearboxes, or is that what you mean by the misunderstood/ignored shpeel from back in the day?

The English language factory service manuals seem to recommend GL-4 transmission oil regardless of whether it is for Warner type synchros or Servo type synchros. However, I have Japanese factory service manuals and transmission service manuals from Nissan Sports which recommend GL-5 for the Servo type synchros. Seems to me that there's a mis-match there.

Porsche recommended GL-5 for their transmissions using the Porsche/Servo-patent steel synchros, and there's traditionally been a lot of debate in the old Porsche world about what is best. I think the experts go with GL-5, and their reasoning seems to make sense. In my personal experience (for whatever that's worth) a good condition Servo synchro trans (either A or B type) with GL-5 is a joy to use.

The two synchro types are fundamentally different, which is at the root of why they chose to go with the 'softer' action Warner type for the North American market. To cut a long story short, Nissan were not convinced that the USA's mass market customer in particular was sophisticated enough to enjoy the rather mechanical synchro feel of the Servo type. This went hand-in-hand with the softer springing and damping, slower steering ratio and wider ratio gearing chosen for that market.

So I have a JDM car with a 5 speed box and presume I have the steel synchros.

You might want to confirm that though. Plenty of 'our' cars have had later Warner type 'boxes fitted when their original 'boxes started to need attention. The period go-to (because they were cheaper than a rebuild) was a 'box from a rusty 280ZX...

I also presume that the stiff, almost binding gear selection is a 'normal' thing for those boxes and may be overcome by putting in the right oil. I have been using GL4 oil which I am now assuming was wrong.

All I can say is that it it IS a Servo synchro 'box, then a GL-5 oil change is worth a try. Worn-out Servo synchros are just as bad as worn-out Warner synchros, so an oil change is not going to fix that. However, a change to GL-5 might help a partially worn Servo 'box to shift a little better.
 

toopy

Club Member
The English language factory service manuals seem to recommend GL-4 transmission oil regardless of whether it is for Warner type synchros or Servo type synchros. However, I have Japanese factory service manuals and transmission service manuals from Nissan Sports which recommend GL-5 for the Servo type synchros. Seems to me that there's a mis-match there.

Porsche recommended GL-5 for their transmissions using the Porsche/Servo-patent steel synchros, and there's traditionally been a lot of debate in the old Porsche world about what is best. I think the experts go with GL-5, and their reasoning seems to make sense. In my personal experience (for whatever that's worth) a good condition Servo synchro trans (either A or B type) with GL-5 is a joy to use.

The two synchro types are fundamentally different, which is at the root of why they chose to go with the 'softer' action Warner type for the North American market. To cut a long story short, Nissan were not convinced that the USA's mass market customer in particular was sophisticated enough to enjoy the rather mechanical synchro feel of the Servo type. This went hand-in-hand with the softer springing and damping, slower steering ratio and wider ratio gearing chosen for that market.



You might want to confirm that though. Plenty of 'our' cars have had later Warner type 'boxes fitted when their original 'boxes started to need attention. The period go-to (because they were cheaper than a rebuild) was a 'box from a rusty 280ZX...



All I can say is that it it IS a Servo synchro 'box, then a GL-5 oil change is worth a try. Worn-out Servo synchros are just as bad as worn-out Warner synchros, so an oil change is not going to fix that. However, a change to GL-5 might help a partially worn Servo 'box to shift a little better.
Thanks for that Alan,

So to confirm, a steel synchro/Porsche type box should ideally run a decent quality GL5 oil, and the Warner/brass type then a GL4 oil is preferable.

And if i understand correctly the box from a 280zx which my car has, should run GL4?
 

Albrecht

Well-Known Forum User
Thanks for that Alan,

So to confirm, a steel synchro/Porsche type box should ideally run a decent quality GL5 oil, and the Warner/brass type then a GL4 oil is preferable.

And if i understand correctly the box from a 280zx which my car has, should run GL4?

All correct. S130-series '280ZX' 5-speed was FS5W71-B, so Warner-patent bronze/brass synchros and requirement for GL-4 oil.
 

toopy

Club Member
@Albrecht you don't by chance happen to know the oil requirements for the popular S13/S14 swap please? I have one to go in at some point in the future. I'd assume a GL5 but going by the above historic confusion?!
 

Albrecht

Well-Known Forum User
@Albrecht you don't by chance happen to know the oil requirements for the popular S13/S14 swap please? I have one to go in at some point in the future. I'd assume a GL5 but going by the above historic confusion?!

S13/S14 'boxes are FS5W71-C type, so Warner synchro and therefore GL-4 oil.
 
Top