1998 Automatic transmission modulator pressure

rtgasman

New member
Help , I have a 1998 412d Automatic that has the 722.375 autobox , I have problems and need to know what the vacuum modulator pressure should be set at , its brown. I have searched everywhere but cannot find the info , rare van I suppose. Can anyone help please
 

lindenengineering

Well-known member
Hey you bloody Devonian what are you driving that old thing about in your part of the worlde ?.

I might have some rebuild info from books & training I had many yurs ago in me native Gloucestershire.

Sit tight 'n I'll have a dig about in the janitor boiler house where I keep this stuff!
Be in touch
:cheers:Dennis
 

rtgasman

New member
Its a campervan , we broke down in Croatia on holiday, had the box "rebuilt" but I still need to check the pressures as don't want it breaking again. Thanks for any info in advance
 

lindenengineering

Well-known member
Well according to the manual I found we have.
Modulating pressure in kp/cm2 min 0,65 to 3,8 max

Working pressure :- 1st gear 6,25 min to 13,15 max
2nd to 4th gears :- 3,1 to 6,4

Gov pressures
prop speed 680 gov pressure 0,75 plus or minus 0.1
1400 1,6 +- 0,2
2050 2,3
3100 3,3
4100 4,6
Hope that helps
Cheers Dennis
 

rtgasman

New member
Sorry for slow reply , thats brilliant , thanks so much .
I checked the modulator pressure it was way to high so I think the gearbox must have been slipping between gear changes causing early death of bands.
Fingers crossed for next big trip , although now this Chinese virus is around Europe I don't think we will be traveling for a while.
all the best Richard
 
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BT50

New member
I have the same auto. 722.375 got number 904.270.00.00 plus 04.389 119 Need to change oil and have been told clutch plates are not compatible with modern oils.....Valvoline maxlife multi vehicle ATFtrans fluid which says recommend mb 236.1 specs......It does not say it is mb approved 236.1 spec......what do you think i should use in auto. Please
 

lindenengineering

Well-known member
You can use Dexron V1/Mercon V or my favorite fill Castrol Transmax for those oldies by goodies application although way back when, I did use Dexron3-H.(now hard to find)
Dennis
 

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