A Friends car.
How can I tell which box I have?
Do I need to open it up to check the ratios.
Or by manually turning the input shaft an looking at the output shaft in every gear.
Or is there a part number on the outside I should be looking at.
Aussie gearbox in LH 202.
He has only just bought it.
Has a 3.36 diff, by the cover on the flange.
But it seems to rev hard for not much speed.
We know that maybe the diff ratio is wrong.
What other diff ratios did Holden have that are shorter than 3.36 & 3.55?
Thanks, John.
M20 or M22 Aussie box
Started by
_LoneOranger_
, Feb 06 2007 06:16 PM
14 replies to this topic
#2
_73LJWhiteSL_
_73LJWhiteSL_
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Posted 06 February 2007 - 07:11 PM
I believe Holden had 3.9 and 4.11 banjo diff rations from 4 cylinders.
The ratio should still be stamped on the ring just after the uni joint unless it has been rebuilt at some stage. Methods for checking this is to turn the wheel or tailshaft and see how many times the other spins, or to check the stamping on the big gear (you need to remove the diff centre to see this).
Steve
The ratio should still be stamped on the ring just after the uni joint unless it has been rebuilt at some stage. Methods for checking this is to turn the wheel or tailshaft and see how many times the other spins, or to check the stamping on the big gear (you need to remove the diff centre to see this).
Steve
#3
toryman76
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Posted 06 February 2007 - 07:30 PM
i think hes asking about identifying the gearbox isnt he? i have the same question... just bought a 253 with a 4 speed hanging off it and im wishing to id the box, m20 or m21?
Cheers toryman76
Cheers toryman76
#4
_73LJWhiteSL_
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Posted 06 February 2007 - 07:44 PM
I thought M20 = 6 cylinder box and M21 = V8 box? (With the exception of the XU-1.)
Both M20 and M21 have a 1:1 top gear so that ratio won't be different, its only the 1st and 2nd gear ratios that are different in the 2 boxes.
Depending on tyre size I can tell you the apprioximate RPMs the car will be doing at 100KPH in top (1:1)
I'm running 205/60R13 tyres on my LJ and at 100KPH in 4th with a 3.36 diff I'm pulling around 3100RPM.
Steve
Both M20 and M21 have a 1:1 top gear so that ratio won't be different, its only the 1st and 2nd gear ratios that are different in the 2 boxes.
Depending on tyre size I can tell you the apprioximate RPMs the car will be doing at 100KPH in top (1:1)
I'm running 205/60R13 tyres on my LJ and at 100KPH in 4th with a 3.36 diff I'm pulling around 3100RPM.
Steve
Edited by 73LJWhiteSL, 06 February 2007 - 07:47 PM.
#5
toryman76
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Posted 06 February 2007 - 08:28 PM
I thought M20 = 6 cylinder box and M21 = V8 box? (With the exception of the XU-1.)
yes this is correct M21's are 8 box's, but M20's still bolt up to an 8 so that is my dilema... not knowing whether someone has put a M20 behind it as a cheaper option to a proper M21 box.
#6
_LoneOranger_
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Posted 06 February 2007 - 09:12 PM
Sorry fellas,
Just realised I hit the H instead of J
The car is an LJ Not LH.
Would a 4cyl LH diff still fit the LJ?
John.
Just realised I hit the H instead of J
The car is an LJ Not LH.
Would a 4cyl LH diff still fit the LJ?
John.
Edited by LoneOranger, 06 February 2007 - 09:13 PM.
#7
_LoneOranger_
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Posted 06 February 2007 - 09:34 PM
toryman76 is right.
I want to know how to identify the gearbox type.
John.
I want to know how to identify the gearbox type.
John.
#8
warrenm
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Posted 07 February 2007 - 07:27 AM
The M-20/21/22 all use the same ratio 4th gear ,which is 1:1.The M-22 which was fitted to the 6cyl 1 tonners has 1st,2nd & 3rd gear ratios close together then a big drop when changing to 4th.It is hard to identify the box while still fitted in the car,there are no external markings.The 3.9:1 diff from an LH will fit the LJ.
#9
TerrA LX
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Posted 07 February 2007 - 08:50 AM
M20 came out behind 6 and 253 V8.
M20 ratios, 1st 3.05:1; 2nd 2.19:1; 3rd 1.51:1; 4th 1.00:1 and reverse 3.05:1.
M21 ratios, 1st 2.54:1; 2nd 1.83:1; 3rd 1.38:1; 4th 1.00:1 and reverse 2.54:1.
the above is for the last of the production and i think the earlier ones shared third gear ratio.
hope that helps.
M20 ratios, 1st 3.05:1; 2nd 2.19:1; 3rd 1.51:1; 4th 1.00:1 and reverse 3.05:1.
M21 ratios, 1st 2.54:1; 2nd 1.83:1; 3rd 1.38:1; 4th 1.00:1 and reverse 2.54:1.
the above is for the last of the production and i think the earlier ones shared third gear ratio.
hope that helps.
#10
toryman76
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Posted 07 February 2007 - 10:20 AM
thanks ALX76
#11
TerrA LX
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Posted 07 February 2007 - 10:26 AM
you can count the ratios by turning the input shaft once and counting how many times the output shaft turns whilst you have a gear selected.
#12
_rorym_
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Posted 17 February 2007 - 05:02 PM
Only real way is to pull the cover...then you are 200% sure.
R
R
#13
_fat tony_
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Posted 19 February 2007 - 06:04 AM
I could be wrong here but I thought m22s had an all allloy case, as opposed to m21 and m21 which are iron ?
#14
limo
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Posted 19 February 2007 - 08:19 PM
assuming box is out, look at input shaft near spigot bush shoulder,
on the spline there maybe 1 or 2 grooves around the spline,
1 groove M20
2 grooves M21
and I thought no grooves meant M22, but haven't seen one myself
on the spline there maybe 1 or 2 grooves around the spline,
1 groove M20
2 grooves M21
and I thought no grooves meant M22, but haven't seen one myself
#15
_LoneOranger_
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Posted 19 February 2007 - 08:34 PM
Thank you for all the replies.
Diff in car is actually a 3.55 not 3.36 as it indicates on external ring.
This now explains the short gearing.
John.
Diff in car is actually a 3.55 not 3.36 as it indicates on external ring.
This now explains the short gearing.
John.
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