I'm rebuilding a Borg Warner T5 from a 1983 280ZX turbo. I have a full rebuild kit and have spent the last couple of weeks reading and memorizing everything there is about the process.

But I'm stuck at the step of removing the tapered bearing from the REAR of the output shaft. The Ford T5/Nissan/AMC shop manuals all state that you simply press off the 5th gear and slide the bearing off. But on mine the splines on the output shaft are larger than the the gear, see below ...there isn't any way I can see to press the gear and bearing off.

NOTE: the shop manuals say 'never' move the larger 1st gear which is to the right of the bearing...its pressed on carefully at the factory apparently so that would rule out pressing off the other end of the shaft... or does it?

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

They maybe heated it up to get it on there, then let it cool and shrink into place. What material is it made of, do you know?

The splined shaft is a single piece end to end, 30 inches long or so through all the gears. The photo makes it look like the shaft is pressed in though.

The issue is that the gear and bearing on the left should be able to slide over the splines and off. The raised step doesn't seem to exist on other T5s. Nissan seems to have done something weird here and even their shop manual is vague about this step.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

I don't have an answer, and I'm only guessing.

Is that all one piece? (The helical gear and the little ring spacer at the bottom of it?) Or are they separate?

Who could you call to ask this? Ford? Nissan? Vinny? RDZ? BW?

People who have rebuilt the Ford/GM T5s are easy to find. Finding someone who has done the Nissan version is a bit harder.

I suspect everything needs to be pressed the opposite direction...off the front of the shaft instead. This disturbs 1st gear which is not supposed to be pressed off though. We'll see.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Well then, by deduction, if you BOUGHT a new 1st gear from the factory it should come already mounted on a new shaft? Then all you would have to do is mount the rest of the donuts on the broomstick and you're done.

Apparently your output shaft is different from the ones they describe in their service manuals, so they would send you the 'correct' one.

????


Or not.

This is the hub you're not supposed to remove...the steel one on the right. I can tell from the way it's pressed on (tiny precision splines) that it's not intended to be pressed off easily (I tried lightly). So I'm starting to think Nissan has pulled a fast one here...like when they created a L28 driveshaft without replaceable ujoints.

Trapped from both sides, its possible that Nissan never intended that the rear bearing be replaced. It also means you can't replace the 2nd gear brass synchro. Despite the internals of this T5 being 100% Borg Warner I'm not sure I understand why it's designed so differently in this area.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Most transmission mainshafts can be disassembled using a press. keep in mind I have a BW that has just the covers of, for sale for $100. (or trade for something) 80k miles on it. BTW, the driveshafts can have new u-joints put on them.

After puzzling over this for day it was an optical illusion... I solved it.

The shaft splines appear twice the height of the ones in the gear for some reason which made it look undo-able. But I gave it a try and the gear pressed right off. So much for my conspiracy theory that the Nissan T5 is different than the others.

Time to get it back together now.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

So, the step had the same outside diameter as the inside diameter of the gear and spacer?

Yup, even with a strong light and a squinted eye the grooves in the gear appeared too small to fit. Quality machining apparently.

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Well alright. So what have you decided for bearings? Timken? BTW, the # stamped on the bearing is Universal. I guess they make em for Mars too.

The kit I bought came with original Koyo and Torrington bearings. Here are the parts numbers. The supplied rear countershaft bearing supplied doesn't come up online, a weird brand/part number.

MAINSHAFT BEARINGS
Koyo Hi-cap LM48510-N (front-tapered)
Koyo Hi-cap 25877R (rear-tapered)


COUNTERSHAFT BEARINGS
Torrington DK-55836 (front cup with rollers)
USA-INA F66263.02 (rear roller)

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Bryan (and Paul) I continue to be impressed by your mechanical abilities. I would have to ponder the consequences long and hard before I opened up my tranny!! I would most probably turn my Z into a push cart if I tried.

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Phil
1981 280zxt - Now in the care my son!
2014 370Z Sports Touring Roadster

I agree with Phil. This is a project I don't know if I have the gumption to tackle! So how about more details Bryan? Is it an advanced home shop project & would you do it again? Are the parts hard to find or expensive? Most importantly - is it worth it?

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280zx NA to T... http://z.modeltrainguide.com