5 speed swap

[CRS]

Hello all,

Getting ready to take the plunge and swap the 4 speed trans and diff from an '83 280zx non-turbo to my '75 280z.

From everything I've read this is the desirable swap for the stock 280z. Better than the late 70's 5 speed setup.

Setup was removed from a running car with 100k+ miles. 

Differential is the R200 with 3.90 ratio.

Any things I should watch out for with the swap?

I plan on changing seals in the trans and diff before installation.

Should I completely rebuild the trans while out of the car, eg syncros or gears?

For the trans tear down is the process straight forward any unusual things to be careful with?

I have rebuilt many engines, trans both manual and auto for GM's (and other domestics) but this will be my first import.

Thanks!

[Dave WM]

I would open it up and inspect for your own peace of mind. Don't be surprised if the rev idler has some chips. You may want to replace the front countershaft bearing if it sounds the least bit bad. Its a little bit on the small side and is very easy to get at. You can take a look at the brass and see if you still have decent gaps. At 100k I would think its going to be ok unless it was abused.

new seals of course and look at the brass tail shaft bushing. If it looks scored up you may want to replace it while the tail shaft housing it out. there is a company that makes the "correct" bush, its longer than the ones most often listed (they are shorter than OE if that matters).

careful not to break the oil gutter its right next to the 1st gear on the ouput shaft, easy to knock off when separating the front section from the adaptor plate. If you do break it replace, as it supples the oil to the tail shaft bushing. On the one I got, it was broken (stuck to the magnet) before I opened up the trans, and the tail shaft bushing was toast (no oil).

you may want to R&R the various o rings for the shifter if you have oil accumulating where the shifter fits into the striker bar. there are 3 IIRC that need to be replaced. And finally make sure you have the right pinion for the 390 gear. you can replace the o rings on that as well to prevent oil loss at the speedo cable.

with the 390 its going to give up some of its hiway cruzing but will be more fun since you can use the 5th more often. On mine (3.54) I don't go into 5th until I am over 70, below that and its bogging (80 is about 3k, 70 2.7k I think).

 

Edited April 2, 2018 by Dave WM

[Dave WM]

the oil gutter is on the same side as the reverse lockout, so when separating the front section, try to make sure when pulling apart that side gets preference to any sideways movement. you want to make sure the front does not come inwards and break of the gutter.

there is a good video on rebuild look up villageland on you tube.

 

Edited April 2, 2018 by Dave WM

[CRS]

Thanks Dave for the feedback. 

I saw a video of a broken oil gutter and hopefully mine is in tact. I don't think this trans has been taken apart. 

I do have the leaks by the shifter you mentioned. I've seen lots for the front and rear seals as well as the gasket in the middle. Have also seen the master rebuild with bearings and seals. Not sure if I've seen the 3 IIRC ones you mention. Do have a recommendation on which ones to buy?

 

[Dave WM]

I would just buy seals, no reason to buy the brass if yours is ok. Pretty sure you can get the OE seals from Nissan. You will need to spend some time going over the drawings to get the right part numbers. You want the front and rear as well as the paper gasket for the front cover. the o rings for the shifter you need to just look up, same with pinion. I don't have those handy. I would save my money on the kits you see on ebay. just get OE stuff that you need. No gasket in the middle (adapter plate) just reg sealant on both sides. One thing to watch out for, IF you decide to take the main nut off the output shaft its most likely rev thread (CW to loosen), but I am not positive if that is the case for EVERY EARLY 81 trans. IF you have the CCW to loosen you may find its NLA, so you would need to reuse it. They have a punch to lock them in place. I wish I could tell you how to know for sure if its reversed or not. The only reason I even think there is an issue is while watching the video I seem to see village land guy remove that one by turning CCW.

[CRS]

I'll start the teardown later this week and post my findings.

I'll also post the rotation of the main nut; left or right handed thread.

Hopefully just the seals/o-rings need to be replaced. I didn't hear any noise or feel any hard spots when turning by hand.

Of course this is low revs compared to the engine output.

Thanks again.

[David F]

A word of caution if you open up the trans....it is tricky to get the shift fork rods and shifter mechanism to mate up properly.  I purchased a used late seventies 5 speed off Ebay (wide ratio due to my automatic differential gearing) and upon receipt I could not move the shifter...uh oh.  I opened up the case, replaced the seals and everything seemed to be fine inside the trans.  Upon reassembly, I apparently made the same mistake and could not shift gears.  Opened it up again and made sure I got the shift rods and shifter lever to mate up properly and all was well.  It was a frustrating.

Otherwise, good luck...should be straight forward swap.

[CRS]

Thanks. Good to know. Right now the trans shifts into the 5 forward and reverse. If it doesn't after I open I'll know why.

[CRS]

Opened the trans today. Oil gutter still in tact. Small amount of metal on the magnetic. Looks like it's from the reverse gear. Also looks like the tail housing brass is worn.

See pics.

Also how do you remove the pin that hold the selector fork on? I removed the nut and washers but the pin won't move. Even tried a bit of force. Any suggestions? 

[munters]

Remove the spring and ball out of the hole with a magnet.

Edited April 8, 2018 by munters

[siteunseen]

 

Seems like it's common for the speedo connection to leak after swapping the transmissions.  Mine did and after reading around on here a lot of others had the same problem.  The seal gets worn in then after you change the position for the new 5 speed it begins to leak.  Here's the part number for the oil seal.

Mine wouldn't stay in 5th or reverse with the S shaped shift rod that I kept from the 240's 4 speed.  Ended up grinding some off the snout and now all is good.

Edited April 8, 2018 by siteunseen

[CRS]

Hello. 

Thanks, I found the o-ring parts on a Nissan site. Yes a very common leak on these trans.

@munters is there a ball and spring on the fork in the picture? I know the other selector rods have them. This looks like a pin with threads to hold it in place.