ZF 4HP22

G

Geordie Jim

Member
Yes, I know it's not a new topic, but has anyone completed this conversion?

I now have a Range Rover Classic box. I've started to strip it but can't get past the first two clutches. Any clues?

I also have a BMW 525E box, in the same state of dissasembly.

The A clutch is better in the RR box but the B clutch is burnt out. So i want to strip both.

The BMW box is not drilled for a start inhibit switch, so I want to use the RR casing.

Just observations from previous posts, I will use the BM sump with the RR Dip Stick, use the RR valve block with the BM filter.
The valve block can be changed with the box in the car, so no problem if the changes don't suit.

the kickdown cable has been cut on both boxes, but this can be fitted with the box in the car. It is a bowden cable and will probably have to a one off special.

Any thing I have missed? Ant comments or assistance welcome, after all, I got the idea on here. :D
 
Thanks for that Harvey, but he's abit vauge.
I'll try this though (from that site)
"" You need to remove the little rubber washers and springs (8 or 9 of them) in the fluid passages between the valve body and the gearsets otherwise you can't get the gearsets out.""
 
Geordie Jim said:
I'll try this though (from that site)
"" You need to remove the little rubber washers and springs (8 or 9 of them) in the fluid passages between the valve body and the gearsets otherwise you can't get the gearsets out.""
Click to expand...

I can only think that if you had the box in front of you and dismantled as far as that then it would be obvious, but if you have, and it isn't, then not having done one personally I don't have anything more constructive to add.
 
Certainly not a lot of info out there on the net as to dissasembly and servicing. I did some extensive googling last year and returned very little in the way of results some usefull stuff which I saved to my computer but all a little light in detail, you are welcom to the files I did find though really there was only one which pertained to Land Rover ZF 4HP22 service info that I would class as slightly useful in a strip.
Far easier to find BW35 and 65 info, complete service manuals in fact.

Graeme
 
Hi Jim,

My understanding is that the ZF will not fit within the tunnel of the P6B as there is a clearance issue. In order to allow it to fit, part of the tunnel needs to be cut away with the replacement pieces remodelled.

Here in Australia, the rebuild cost of the ZF tends to run between 3 and 4 times the cost of having a BW35 or 65 rebuilt, so I am advised.

Ron.
 
I finally found how to strip a FZ box!!!

I only cheated a little.....
I just rang JPAT Transmissions and they helped me!

So, i have stripped the RR box ( so its lighter to handle), put the pump and bellhousing back on, and fitted it to the engine.

suprisingly there is clearance for the bellhousing, not much, the throttle rod is close, but all the old rear brackets have to come off, and new fabricated.

When I am satisfied with the fit I will take engine and box out to clean and paint the engine bay.

I've got pictures on Flickr, here's the link.
http://www.flickr.com/photos/60263021@N ... 088997188/
 
Same here. I presently have a non-functioning BW35 in the car, and two ZFs (Discovery and BMW) in the garage. Project to start soon.
 
OK, time for an update. Repairs to garage roof and the winter delayed events.
I have used the Range Rover case( 1992), because the BMW ( 1983 525e)is not machined for the inhibit/reverse switch.
Also the RR box has a different valve set. There are 8 seals under the valves, plus an angled one.
The BMW doesn't have the angled one. So I had to use the RR valves.
When stripping the BMW, I couldn't remove the tail shaft needle roller inner race. A puller and blow lamp failed so I resorted to a Dremel.
Now awaiting a costly replacement.

The box is now rebuilt ( apart from the extension housing) with new seals and gaskets, and the sump is next to go on. Then the box will be mated to the engine.

The engine now has SD1 heads and front cover, and a 3.9 camshaft.

I'll get some pictures on soon.

Jim.
 
I pulled my two ZF boxes out of their dark corner today and laid them next to each other. First thing to take a look at was, after Jim's post, the situation regarding inhibitor switches. As he says, the BMW box is not fitted with one a la the Disco box, so what now?

The situation is: a low mileage Bimmer box in good nick that I didn't want to pull apart because I have neither the required knowledge, nor the funds to pay somebody else; an unknown Disco box from which I wished to obtain the bellhousing, flex plate, torque converter and valve body.

Do I now have to look at using the Disco case and inhibitor switch? How did the BMW achieve start inhibit? Can something be adapted?

Meanwhile Brown Rover is sitting disgraced in the garage, leaking transmission fluid onto the floor while I summon up the motivation to remove the dead BW35. I've worked out that I shouldn't need to raise the car any more than 8 inches to drop it out so I'll go around and measure up my mate's ramps as soon as possible.
 
the BMW's start inhibit is probably done through a switch on the shift mechanism inside the car (gear lever). Many cars do it that way and I would imagine that you could rig up something similar using parts from a vehicle that does it that way. Scrapyard time, I think......

In the short term, if you can trust yourself to ensure that you are in neutral or park, you could bypass the start inhibit switch
 
Warren,
Not surprised you don't want to disturb a good box.
This was my first time delving into an auto box, yet to find out if I did correctly.
Has the RR box got the inhibit switch fitted?
The boss is there on the BMW box, needs machining out, and the 6mm retaining screw drilling and tapping.
You would need to remove the sump and select lever, which is straight forward. The select lever is ready to operate the switch.
Probably a good idea to remove the sump anyway to change the filter and clean the magnets.

Pictures soon.
Jim.
 
Hi Jim, you're right, I didn't want to disturb the good box. I know the car it came from, and had my mechanic give it a basic check over, so I was prepared to put it in the car with no further thought as to its internals; just a good flush and refill when done. I'm running a small risk it will poop itself at a later date, but the odds are good enough to not worry about it for now.

Anyway, yes, the Disco box has the inhibitor switch installed, and the boss is plainly evident on the BMW box. But what happens to the swarf and shit generated by machining the hole? Is that what you mean by removing the sump? And going by other your comment above, can I assume it's just a case of screwing the switch into the new hole and it's all go?

Some time after I wrote my last post I'd conceived that the BMW's start inhibit must be tied up with the selector, but I didn't want to go down that path. At first inspection it seems there won't be any insurmountable difficulties in adapting the existing selector to the ZF, and I want to a) maintain the original appearance; b) not do anything that can't be reversed. Therefore going on your advice, Jim, machining the BMW case sounds like the preferable option.
 
Meant to say, Jim, your photos have inspired me to clean up and paint my new box and bell housing. You're putting me to shame.
 
Warren,
changing to the ZF is irreversible, you need to cut off the existing gearbox mounts( from the base unit) and fabricate new.
The inhibit switch fits in a round hole with an "O" ring seal. Its retained with the fitting in the same way as the distributor.
Do you have the crankshaft adaptor? It has the six holes to fit to the crank and four tapped holes for the spacer and flexiplate.

Jim.
 
There's something that possibly fits that description (crankshaft adapter) in the box of goodies that came with the Disco box. I'll take a look when I get home, post a pic perhaps. I'll also pull the inhibitor switch out of the Disco box and take a closer look at how it's fitted. Is it simply a case of machining the hole in the BMW boss and cleaning the swarf out of the sump?

As for the gearbox mounts, I'll cross that bridge when I come to it, but I was hoping to fabricate something that can make use of the existing ones.
 
I've been reading that these gearboxes are ruined if you give the engine high revs while in N or P .Something to do with an iron sealing ring wearing a groove in a housing.
 
DaveHerns said:
I've been reading that these gearboxes are ruined if you give the engine high revs while in N or P .Something to do with an iron sealing ring wearing a groove in a housing.
Click to expand...

AFAIK that's right, the sealing ring (or whatever) fails and that means the clutch is dragging all the time.*

*Disclaimer. I may have dreamt all or any of that.
 
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