astra g 6 speed conversion adventures

corsaZ22se

Senior Member
i know of a lot of m32 boxes that have failed before 40K miles. :( that's just running stock power. M20 is the same box just a smaller diff.
my F23's have been trouble free apart from the ex post office van one which had EP oil in it and chewed a syncro ring :cry:
the one from the vectra B has done over 170K miles with out any more than a drive shaft seal (my clumsy fault when test fitting drive shafts in the Corsa :mad:)
like marmite really.
 

evocarlos

Stupid Bollocks
Staff
new bearing came bright and early this morning 9am :)
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press at work
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pack restacked and new end bearing going on
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other shat almost done
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all done with new bearings had to go with the vxr 6th gear the diesel one was damaged and i decided not to fit it
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outer races removed from the end case
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diff back in and shimmed up with a 1.5mm it was 1.3mm but i guess it was to slack
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just need to pop the end case on and install the shaft seals then it can go back in the car :)
 

evocarlos

Stupid Bollocks
Staff
i know of a lot of m32 boxes that have failed before 40K miles. :( that's just running stock power. M20 is the same box just a smaller diff.
my F23's have been trouble free apart from the ex post office van one which had EP oil in it and chewed a syncro ring :cry:
the one from the vectra B has done over 170K miles with out any more than a drive shaft seal (my clumsy fault when test fitting drive shafts in the Corsa :mad:)
like marmite really.
ive got 4 m32 all over 80k ive even done a 6th gear bearing on an m32 that had done 124k but that was the only fault just one bearing
my f23 started playing up at 17k miles with the sloppy shifting and poor cold shifting then ones it got some power the 3rd gear syncro just went the 2nd astra had 70k miles and completely standard that shat 3rd gear syncro to
moral of the story is the f23 is crap as its unserviceable while in a car with the m32 it dont really matter if it only does 40k it can be fixed by jacking the car up and pulling the end case :)
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dewismotorsport

Senior Member
Good work (y)

I think it’s hit and miss on the boxes tbh. I’ve had no issues with the track astras where it gets death but then the daily one I bought with a crunching 3rd. But then I also know of the F23 running over 800bhp on the drag strip without dramas.

Same with the M32 I know loads of people who have had issues with them either whining or crunching.
 

evocarlos

Stupid Bollocks
Staff
test spin of the rebuilt box on the bench

also started to strip the 3.9fd box just needs a 6th gear bearing and the planetary gears doing the owner must of been wheel spin happy lol
lack of oil during running (case mod to fix it)
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pretty dirty to
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not sure that one bit is ment to be sideways lol
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already got the diff sorted and there's a new 6th bearing in my tool box
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evocarlos

Stupid Bollocks
Staff
the trick with the M32 is to run more oil, a minimum of 3 litres and a maximum of 3.5 litres (y)
with the stock end case it needs the notch or it will still burn the trapped oil on the 6th gear bearing :) I run 3l but only to keep the noise down from single mass
 

evocarlos

Stupid Bollocks
Staff
went to a scrap yard with some friends to try and get a clutch for a car while walking round there was a pile of gearboxs my keen eye spotted the m32 on top and asked how much £80 that will do me :) its a diesel box but after inspection its all very very good it dont even need a 6th gear bearing one to clean up and sell on

also setup the sand blaster and started cleaning some of the cases
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the 4.17 gearbox went back in the car today
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had to mend the locking ring on the gear cables it had snapped some glue and a bit of stainless welding rod soon had it as good as new
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jensenvk

Member
what is the trick of getting the thickness of shim for M32 diff right? I have rebuilt the diff and measured the gap between the flange and the bearing surface by using a feeler gauge. Thought the gap should be 0.15 mm +-.05mm

However, I can hear a slight whining noise starting around 50 mph. Is the shim too thick or too thin?
 

evocarlos

Stupid Bollocks
Staff
what is the trick of getting the thickness of shim for M32 diff right? I have rebuilt the diff and measured the gap between the flange and the bearing surface by using a feeler gauge. Thought the gap should be 0.15 mm +-.05mm

However, I can hear a slight whining noise starting around 50 mph. Is the shim too thick or too thin?
that will most likely be the large bearings on the pinion shafts pitted if its still whining
 

jensenvk

Member
that will most likely be the large bearings on the pinion shafts pitted if its still whining
Thanks for the tip Carl! Looks like I'll need to rebuild the gearbox after all.... How did you manage to measure the correct shims for the shafts without special GM tools? I know some workshops use special measuring "pipes" from Kent Moore that they put on top of the shafts. Have no idea where to buy them..
 

evocarlos

Stupid Bollocks
Staff
Thanks for the tip Carl! Looks like I'll need to rebuild the gearbox after all.... How did you manage to measure the correct shims for the shafts without special GM tools? I know some workshops use special measuring "pipes" from Kent Moore that they put on top of the shafts. Have no idea where to buy them..
missed a set of kent moore m32 tools the other day on ebay
but i just got with the 1.0mm and the 0.9mm on the 2 pinion shafts i do also not use timken bearings the snr and fag kits are all i buy now
 

jensenvk

Member

evocarlos

Stupid Bollocks
Staff
You mean this one:
https://www.ebay.com/itm/Kent-Moore...690302&hash=item211fdbc8f0:g:E9sAAOSwUKxYloOU
I will also try and get the new version of the end case with improved oil flow. The uprated bearings aren't enough apparently.
is that the tool for the m32 ?
it's a misconception that the uprated bearings fail the issue is not the brand of bearing its the fact the oil is not replaced in the 6th gear bearing cavity often enough and that when in 6th gear the forces run all the way down the input shaft to the end and then all the way back down to the pinion shaft to the ring gear the uprated end case does make the box support alot more power the bearings are much bigger in size
a simple case mod can help swap the oil out in the 6th gear bearing prolonging the life substantially
14k miles covered with the box getting 380nm with snr and the case mod with no signs of any problems
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jensenvk

Member
Sorry, it is the wrong tool. Looks similar but it is the wrong one. I did some heavy research and found out that the tool code is DT-60000-120 Kent-Moore.
I have tried to get the Opel dealership to sell it to me but they seem to be a bit difficult.
Gonna send a request for quotation to gmtoolsandequipment.com

Did you do the mod on the old case version or is it the new version end case?
 

evocarlos

Stupid Bollocks
Staff
Sorry, it is the wrong tool. Looks similar but it is the wrong one. I did some heavy research and found out that the tool code is DT-60000-120 Kent-Moore.
I have tried to get the Opel dealership to sell it to me but they seem to be a bit difficult.
Gonna send a request for quotation to gmtoolsandequipment.com

Did you do the mod on the old case version or is it the new version end case?
old case tested for 14k miles with 380nm daily with no apparent wear
i then went to uprated end case when the clutch snapped and damaged the syncros on 3rd and 4th
 
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