@Patcon Which internal clearance are you referencing?

Here are a couple of them:

1. baulk ring to glear clearance ( page - MT-11)

2. gear end play (page - MT-11)

3. front counter shaft bearing (page MT-7)

280zx-manualtransmission.pdf

@heyitsrama

thanks for that. I was thinking of the gear end play.

I suspect there is nothing for me to check with the baulk ring to gear clearance because they are all new.

Don't know on the front counter shaft

I've been stumped on the front counter shaft, it seems like the value changes based on where i measure the bearing to the faceplate, as if its not sitting flat in the housing...

It might be how I am using the end of the digital caliper to take the measurement, there could be variable in where I am holding it.

If you are looking for a way to torque down the main nut, i used an autozone inner tie rod tool rental. It worked like a charm, after that you should be ready to measure the gear end play.

 

So the countershaft front bearing shim, If I don't do this test (MT-7 to 8), what is the downside risk? I believe we reused the existing shim that was in the transmission

I think that the shim is meant to correct for the expansion of the aluminum case when it heats up.  And/or it locks the outer race down so it won't spin.  It's basically a preload shim.  Too loose and the race might spin.  That's my guess.

I also remember finding that all of the ones I measured were 0.3 mm.  Like Nissan figured out their manufacturing problems and they were all identical.

The picture seems to show that it rides on both races but I thought it only contacted the outer.  Could be wrong, can't remember.

So can somebody confirm that I am checking these in the correct spots?

1st gear

2nd gear

 

3rd gear

We don't have enough clearance on this side of the gear but there is extra on the front side between the bearing and clip

Reverse

5th gear

We do not have enough clearance at this location. We only have 0.0025" versus min .0122"

The front bearing shim is important for distributing the axial forces over the two cluster shaft bearings. No shim and the bearing in the adapter plate has to carry all the forces and waer faster.

You can determine the shim thickness using plastagauge. I thick the yellow (0,2 to 0,4) would be best choice I think.

The clearance on 5th gear is very tight and will probably cause lubricating issues

47 minutes ago, EuroDat said:

The front bearing shim is important for distributing the axial forces over the two cluster shaft bearings. No shim and the bearing in the adapter plate has to carry all the forces and waer faster.

You can determine the shim thickness using plastagauge. I thick the yellow (0,2 to 0,4) would be best choice I think.

The clearance on 5th gear is very tight and will probably cause lubricating issues

I don't totally understand the technique for checking the front bearing shim. Can you clarify that for me?

Also how do you adjust the rear clearance. You torque the nut to spec but then I don't have enough clearance. Do you then back it off?

Are the other locations the proper places to check?

Do we need to move the large bearing forward to get the clearance on the backside?

5 hours ago, Patcon said:

I don't totally understand the technique for checking the front bearing shim. Can you clarify that for me?

Also how do you adjust the rear clearance. You torque the nut to spec but then I don't have enough clearance. Do you then back it off?

Are the other locations the proper places to check?

Do we need to move the large bearing forward to get the clearance on the backside?

Easiest way to gain the right clearance on the rear gear is to add a shim between the large washer (in your photo you are holding it with your finger and thumb). If you buy the thin brass shim stock you can cut a washer with a good pair of scissors. Add the shim stock to the gear side of the washer to add clearance.

When I'm home I will take some photos of what I mean with Plastagauge and how to use it on the bearing.

 

I just checked my plastigauge stock and the brand Plastigauge would be green (PL-C) for the clearance 0.175 to 0.5mm.

It is easy to use. Just break off a couple of short 15mm lengths and place them on the bearing. Place the plastigauge on one of the cage humps across to the outer race. You can hold it in place with a dab of play-doe on the cage section.

Bolt on the front cover with gasket to the correct torque. Open it up gentle and don't twist the cover.

The section of plastagauge over the outer race will be flatter than the rest. Use the gauge setting on the packet to determine clearance. Plenty of videos on youtube.

If you can't find any plastagauge, PM me.

Edited August 16, 20222 yr by EuroDat

The fifth gear clearance can be corrdcted by adding shim stock between the washer (pos 21) and overdrive gear bushing (pos 20).

Shim stock thickness 0.01 (0.25mm) is easy to cut with tin cutters.

You could try to find shim washers the right size. Google "shim washers din 988". Go for the right inner diameter if you can't find one with the right dimensions. Trimming the outer diameter is easier than the inner diameter.

Thanks Chas!

That's perfect.

On 8/15/2022 at 7:45 PM, Patcon said:

Do we need to move the large bearing forward to get the clearance on the backside?

Do we need to shift this bearing forward?