33 replies to this topic

[MFM]

I'm sorry but I know this topic has been flogged and I have read some historical posts relating to how to identify an XU1 M21 gearbox externally (not internally), and its still not clear cut? I have an opoportunity to buy a spare box for my car (XU1) which I've been told is an M20 but was originally out of a genuine XU1. I've attached the casting date in the photo but its very unclear but looks like 'CF2'?? is the input shaft a little bit different??  

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[grumpy xu1]

Hi Mark, there's usually 2 grooves cut in the circumference of the shaft near the end of the spline that inserts in the backside of the flywheel just before it steps down for where the spigot runs. The gear set will be numbered if you remove the side cover where the selector linkage goes in. It's on the side of 1 of the gears & you'll be looking for the last 3 digits like 899 ect. The cast date should be a number or numbers,like 10 (date) then a letter for the month (f) then a number like (2) for the year, so that would be 10th July 1972 ect. Gary.

[S pack]

Hi Mark, the XU1 Aussie 4 spd (2.54:1 1st gear) is an M20 not an M21. The genuine XU1 input shaft typically has two grooves whereas the std 6cyl 3.05:1 1st gear ratio Aussie M20 only has one groove.

That said exceptions to the rule do pop up now and again. For example I have an old genuine XU1 544 input shaft that has no grooves.

Short of taking the side plate off the box to see if it has the 899 XU1 cluster gear you could put the box in 1st gear and count the number of rotations of the input shaft to complete 1 full rotation of the output shaft.

Date code wise it should be numbers for the day of the month and the year and a letter to represent the month.

[MFM]

So Gary/Dave, the two grooves that you both mentioned that are around the input shaft. Appears this one doesn't have them? Sounds like I'm going to have to take the inspection plate off and look at the gear numbers on the cluster, then I will know for sure. Do you happen to know the whole number I am looking for on the cluster? 

[S pack]

2823899

 

If the external paint on the box is original does it have XU stamped in yellow on it?

Edited by S pack, 05 February 2019 - 08:39 PM.

[Bazza]

Hi

 

Cheers

 

Bazza

 

 

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[grumpy xu1]

2823899
 
If the external paint on the box is original does it have XU stamped in yellow on it?

Yeah, as Bazza states, "providing" the factory paint & markings are still on the box, it will be a colour "similar" to red oxide, with yellow markings on the left hand side of the box & the top, the xu1 has a "xu" & the gtr has a "gl" Anything else would mean the "case" at least,is from something else. Gary.

[u1 71]

The Ck gear box has no rings on the input shaft

[grumpy xu1]

The Ck gear box has no rings on the input shaft

All of them ? I have a friend who has 1, I will have to ask him to check his.

[u1 71]

If your friends car still retains its original hood lining it will have 82911 written on the top side

[MFM]

Ok thanks for the replies. I just got up this morning and degreased the outside casing and the yellow stensiling on the casing shows 'ZF' and linkages which came off same car appear to me to be early Commodore by the look of the gear stick. Weird thing is that I followed the advice of the early posts and put a paint mark on the input shaft and a corresponding mark on the output spline placed it in 1st gear (I think I did it right) and counted the turns. Came to about 2.2 but definitely not 3 turns. Mabey I did this wrong but I found neutral using the rear selector (closest to diff) moved it forward one click (towards engine) so assuming this is 1st gear?. Anyway doesn't have 'XU' stensiled on casing like my unpainted box in my car so god knows what XF is out of. Bazza's way is the only true accurate way to determine this so will do that as only want this as a spare.

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[S pack]

I suspect ZF is out of a VH Commodore and the date code might be 1982 not 1972.

Does the part number cast into the front cover start with 743 or 993?

Edited by S pack, 06 February 2019 - 07:50 AM.

[MFM]

'993'. Gear linkages look very much like Commodore so you are probably spot on

[claysummers]

2.19:1 sounds very much like you have a standard M20 box in second gear rather than first.


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[S pack]

'993'. Gear linkages look very much like Commodore so you are probably spot on

That is the oil seal type front cover that was introduced into production after XU1 production had finished in 1973. Aftermarket XU1 input shafts use the oil seal type front cover however all genuine original XU1 2823544 input shafts are the oil slinger type that use the 743 cover.

 

If it is a std 3.05:1 1st gear commo box the input shaft part number will be 9930923 and the cluster gear will be 2813493

 

So many times over the years I've been to look at 'genuine original XU1 g/boxes' for sale to find they are just std 6cyl boxes.

Edited by S pack, 06 February 2019 - 08:24 AM.

[MFM]

Yeh you could be right Clay. Mabey someone may view my post on how I did this and correct me on where I went wrong . Also if it turns out to be early Commodore and its in VGC is it worth buying for spares as not sure what parts are interchangeable with the XU1 box? If so how much should I be paying as have no idea.

[S pack]

Yeh you could be right Clay. Mabey someone may view my post on how I did this and correct me on where I went wrong . Also if it turns out to be early Commodore and its in VGC is it worth buying for spares as not sure what parts are interchangeable with the XU1 box? If so how much should I be paying as have no idea.

Basically everything bar the front cover, the input shaft and cluster gear. If all the gears are in good nick maybe $200 - $250?

Yeh you could be right Clay. Mabey someone may view my post on how I did this and correct me on where I went wrong . Also if it turns out to be early Commodore and its in VGC is it worth buying for spares as not sure what parts are interchangeable with the XU1 box? If so how much should I be paying as have no idea.

A pic of the selector side cover plate might help.

[MFM]

See attached

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[claysummers]

It’d have to be in vvgc to be worth more than about $150 - $200 imho. Dime a dozen and not very strong.


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[S pack]

The selector side plate originally had a spark advance inhibitor switch fitted where that hex head plug is.

 

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[claysummers]

The selector side plate originally had a spark advance inhibitor switch fitted where that hex head plug is.

So box is 1976 or later


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[grumpy xu1]

So out of curiosity, did the xu1, at least lj, only leave the factory with 899 cluster, or was there other ratios fitted ? Is there paperwork stating that ? Gary.

[S pack]

So out of curiosity, did the xu1, at least lj, only leave the factory with 899 cluster, or was there other ratios fitted ? Is there paperwork stating that ? Gary.

AFAIK the only box factory fitted to LJ XU1 was the XU box with the 899 cluster.

If I recall correctly Frash says that his 72 Bathurst XU1 has the M21 497 cluster from factory and he has a GMH book stating the V8 M21 ratios were optional in XU1 in 1972.

There was the optional 2.32:1 1st gear XU1 box in 1973 but if any cars were factory fitted with this box then it probably wasn't many.

[Bigfella237]

You could try lightly rubbing some chalk or even soap over the raised letters of that date code to highlight the digits, I suspect that there's another number at the start of that code and that it may actually be "10F2"?

 

Also, on the rear face of the main case on the side (the only part not covered by the rear extension housing) there should be a stamped serial number beginning with "T" with up to six numbers following.

 

That will absolutely tell the difference between 1972 and 1982.