Thread: zf governor replacement tips

its going to drop some oil yes, a large metal sheet and a removalists blanket will take care of that.

you are likely to snap at least one of the exuast bolts but one they are snapped pinging them with a center punch or putting a stud extractor on them will pull them 90% of the time.

soaking them overnight from hot with WD 40 diesel or any other penetrating lubricant you can get will help you out.

Im assuming that youre replacing the rear governor, given what you've got available I would suggest that pulling the whole box out then splitting the tcase off before reassembling it would be better way to go than trying to drop just the Tcase.

Auto Trans work really needs to be done in a very clean envioronment and whats under most vehicles doesnt fit the class.

One trick is those load straps around the chassis rails and one or 2 trolley jacks. Thats how now get mine in and out.

Like Dave says, it CAN be done in the vehicle but on a hoist in a clean workshop is ideal, under the vehicle lying on your back ISN't. You will require new governor seals (Square section Orings basically) and Torx bits to remove and refit the unit. Are you changing it out for a lighter one? That will help make the upshifts later.
Fitting the sealing rings requires lots of care, use the Dex3 oil as assembly lube. ALSO, if you are fitting a used governor, remove the plunger and weight etc, and use a kitchen scourer (Plastic one, not steel wool ) to buff the plunger/ piston to ensure it isn't sticking in the bore. DO NOT allow your sweaty fingers to touch it afterward, and use Dex3 oil to reassemble NOT vaseline or grease etc. This is why we recommend clean environments for assembly.
MAKE SURE YOU ARE AS CLEAN AS A SURGEON HAS TO BE as any amount of dirt WILL cause sticking of the governor weight / plunger etc.

An ICV100010 transfer case input seal will be required, aswell as a trans output seal RTC4650 and a trans extension housing gasket. Don't forget the Oring under the adapter shaft bolt head, and you will need 80w90 for the transfer case, 2.75l and Dex3 for the auto.

JC

I havnt bought the bits yet .Im hoping to find out everything I need here first and then buy all the parts at once .
Whats the go with the heavier governor mentioned ? Is that for a different model ? Whats the best ?
Ive read not to use the existing governor as its a waste of time cleaning and buy a new one instead . Is this true ?

How does the governor and its internal parts function . where does the crap get stuck in there and cause the problems . Id clean it instead of replacement if it is a good option to clean .Anyone got a diagram of the governors part breakdown ?

So, why are you replacing it? Is it sticking / holding 1st gear from cold? The lighter weight is on later 4HP22 from 1990 (3.9V8) onward, there were also a few valve body changes and the cam profile for the kickdown cable is different helping the later firmer shifts.
If you want my advice, with such an old trans i'd be sourcing a good used Disco or later RRC auto instead of persisting with yours. You will have to upgrade the cooler and lines too as they are bigger ID.

they can be quite cheap as most people won't fix their V8 Discos and Rangies due to the cost etc... I have 3 lying around and can't sell them

JC

Yes its sticking in first when cold for anything between 200 meters and a klm before the change then its fine from then on .

I did find one and only one guy on the web who used a thinner trans fluid and the problem went away but for how long it would last he didnt know .
I think late model cars now are using some light grades of tranny fluid . Maybe thats worth a try to buy a bit more life out of the box .