extension bushing replacement?

[zed]

My Nissan Hardbody pick-up with FS5W71C 5-speed gearbox has started making a high-pitched whirling noise as I pull away. The noise stops very quickly - as soon as speed reaches about 5mph. For the last year I've been replacing the output shaft oil seal every 6 months, because it leaks, I'm thinking it's a worn extension housing bushing, causing both leakage and noise. If I have to replace the extension bushing, can I do it myself - I have basic mechanical skills? My Haynes manual does show the FS5W71C gearbox, and it looks like I could just remove the rear section of the gearbox?. Can I do the job without removing the gearbox? I would prefer not to remove it. thanks for any advice

[datzenmike]

I would remove the transmission. I know in the 620/720 there's a crossmember for the rear mount just below and the rear case would have to be pulled to the back by at least it's own length to lift off. Additionally it has to be 'finessed' into place when assembling to engage the shifter to the shift forks. It's a bitch to do even with it out.

 

The bushing, according to my FSMs, states to not remove the bushing but replace the rear extension housing as an assembly. Wow.

[zed]

Thanks Mike. Sounds like this is beyond me... shit. I don't like taking my truck to a workshop - I always find something they've screwed up when I get it back.

[datzenmike]

Take the tranny out yourself. Find anothere tail in a wrecking yard. Hell I have a '79zx 5 speed and put an '85 SD25 diesel tali on it.

[ggzilla]

+1, don't let another mechanic decide how much money it will cost you. And then mess up the job.

 

You can replace the bushing if you can locate one with the right dimensions, perhaps through a bearing distributor (just don't ask for a Nissan bushing). I know that for the small Datsun transmissions guys have done it even though the factory service manual says "replace as a unit".

[zed]

thanks mike and ggzilla: trouble is, there are very few Hardbodys in wreckers yards here - people in South Africa keep them until they fall apart with age. My plan is to take the gearbox out myself, then remove the 'tail', and take it to an engineering shop, to either press in the bushing I will order from Nissan, or have one made by the engineering shop. If I can't re-assemble it myself - which is likely if Mike says its a bitch - I'll ask a mechanical friend to help me.

[ggzilla]

Sounds like a great plan! Except that (at least here in USA), you can't order a bushing from Nissan instead they sell the entire extension housing.

 

By the way, it doesn't have to be a hardbody. The same transmission series was used by other Datsun/Nissan vehicles. Just need the same size/type of extension housing.

[zed]

thanks for the tip - I see in my Hardbody's handbook that the same gearbox is fitted to all the other models in the range, from those with the L16 up to Z24 motors, in the 4x4 Tracker model?

[Dime Dave]

I would remove the transmission. I know in the 620/720 there's a crossmember for the rear mount just below and the rear case would have to be pulled to the back by at least it's own length to lift off. Additionally it has to be 'finessed' into place when assembling to engage the shifter to the shift forks. It's a bitch to do even with it out.

 

The bushing, according to my FSMs, states to not remove the bushing but replace the rear extension housing as an assembly. Wow.

 

I looked into replacing the bushing on one of my transmissions and was told the same thing.

 

The story I heard was the bushing was actually cast into the tail housing and machined afterward. So even if you found a bushing that would fit, the chances of it being concentric with the tail shaft once installed was remote.

 

Don't know if there is any truth in this, but I'd go JY shopping before trying to replace the bushing.

[zed]

Well, that was quite a mission. Took most of the last 2 days. All my clothes smell of 75W90 now. Took the transmission out, tail off. Found an new aftermarket extension housing bushing at a transmission workshop - a cool R500 later (for a 2 inch soft metal tube!). Plus a new yoke and U-joint, cos the seal had worn a groove on the old yoke – R450. Plus engineering to press in and hone bushing – R700. Plus oil, gasket-maker etc – R300. Plus my mechanical buddy – R500. Still cheaper than a Nissan dealer tho. And no hidden damage like I found this time - the gear-stick boot was cut off, and the bolts on the tranny top cover stripped – thanks to Nissan last time. The workshop offered to make up a phosphor-bronze bushing – but I would then have to use ATF in the tranny.

[ggzilla]

Glad to hear it worked out less expensive than a new part.

[datzenmike]

The workshop offered to make up a phosphor-bronze bushing – but I would then have to use ATF in the tranny.

 

Your transmission has phosphor bronze balk or synchro rings in it now. You should be running 80 w 90 weight GL-4 gear oil to protect them. GL-4 is recommended for Nissan transmissions. The bottle should say 'yellow metal safe' on it. Do not use GL-5 oil. GL-5 is formulated with 50% more sulphur compounds in it that will attack any copper bearing metals like synchro rings and is used in differentials that need the extra anti scuff additives.

[zed]

even better - the loud clang which the drivetrain used to make on pull away has disappeared - must have been U-joints, which I replaced. Years ago I bought a 25 litre drum of 75w90 GL4, recommended in the owner's handbook for Hardbody transmissions