All,

Does anyone know what Rover means by "reverse gear interlock valve siezed"? The only other reference to it in the rover manual is the "gear selector interlock" and it's electronic -- no "valve" (that implies fluid, not electronics). I've attached the gear interlock portion. There is an inhibitor switch -- is that related?






The trans will not go into reverse, however, all forward gears are working great. When I added "SEA FOAM" to the tranny this problem started. Before that reverse was 'slipping" -- see my other post about 93 SWB RR transmission problems.

Thanks,
Tony

 

Tony

I have never heard of SEA FOAM, who recommended it and did you add it to the existing fluid or did you drain the box and refill with SEA FOAM??

Also is the manual you are using for a '93 RR, I understand that there was never a manual published for a '93 RR, not that it should make much of a difference whith the gearbox but if the problem is electrical it might because some of the electricals are quite different in the '93 as I'm finding out.

 

I added the sea foam (10oz) before draining, filter refit, refill, so half of the stuff is still in there. A guy at the parts store ran on and on about it. I need to go get my money back probably. I'd also add a be-otch slapping if it wouldn't land me in the pokey.

On the manual -- I have a separate 93 manual for electronics, but it doesn't match the wiring entirely. The manual I posted shots from is 1990-1994 RANGE ROVER WORKSHOP MANUAL North American part number LHAWMUSA01. It goes to Feb 1993 in the footnotes. This shop manual has ZERO details about servicing the transmission. I don't know if I can remove the control body to fix this or if it's electronic. It's a real guessing game AND I have a manual. The other aftermarket manual are completely out to lunch concerning transmissions.

the terms "gear interlock" match and an electronic problem could be an explanation. I just can't find any mention of the 93 "reverse gear interlock valve" anywhere else in the manual (a really good reason for forum research like this)... There are zero pictures of it OR references to it in diagrams of the automatic gearbox section. Just page 44 FAULT. The other mention of it is in the electrical section that I've copied. Yes, the 93's seem to be in a electronic manual pergatory -- some things are right, others are not. I know the alarm wiring diagram is off base.

VIN PA627122, ABS, 9/92 mfg date, 1993 model year, SWB.

Thanks for your help...

-Tony

 

On the 1993range rover documentation I have a couple theories:

1. the writer thinks the knowledge is worth it's weight in gold and they are going to hold onto all the secrets so they can make a living off it as a mechanic until the end of time.
2. the writer has litterally no idea of what they are talking about, they just mess around with technical words and start making up things that look good to get words and pictures in there.
3. the writer is somewhat smart but a VERY heavy drinker and they forget where they were and what they were speaking about.
4. they started off with knowledgable people and some documentation, then Rover fired selective prople midway through production so they people left were in category #2.

 

Tony

I take it we are talking about a ZF box?

I have a manual which is on CD, date line is 1990 > 1994 it mentions under FAULT SYMTOMS that the PRIMARY REGULATOR IS STUCK as the cause of NO DRIVE IN REVERSE GEAR.

 

On the 1993range rover documentation I have a couple theories:

1. the writer thinks the knowledge is worth it's weight in gold and they are going to hold onto all the secrets so they can make a living off it as a mechanic until the end of time.
2. the writer has litterally no idea of what they are talking about, they just mess around with technical words and start making up things that look good to get words and pictures in there.
3. the writer is somewhat smart but a VERY heavy drinker and they forget where they were and what they were speaking about.
4. they started off with knowledgable people and some documentation, then Rover fired selective prople midway through production so they people left were in category #2.

Tony

I like that.

I once attended a course, there was a married couple in the class she was very out going, had a dynamic job, always dressed smart, looked athletic etc, he was a big, over weight lazy sort of a fella who look like he didn’t have a bone in his body, they looked theoriginal odd couple.

He was a writer, so I thought he was a novelist/author, turned out he was a “Technical Writer” so I asked in what field he said “Anything and Everything”, when I asked how he could be across anything and everything he said the companies just send him “Notes and pictures” on how something works and he goes from there and fills in the blanks – I couldn't believe my luck, at last I’ve found the fella who writes VCR and Range Rover manuals but at that stage of his career he said he hadn't been approached by either "Yet".

As a consequence I haven’t a lot of faith in technical manuals, but I still live in hope, when you have a Range Rover you have no choice J

 

Hello Bill,

Classic story on the technical writer. I heard there are 3 type of people:
1. those who make things happen
2. those who watch things happen
3. those who wonder "what happened"

Right now I'm in category 3 concerning the rover transmission.

Yes, ZF. Any mention on the CD of where the primary regulator is located? I'm wondering if I can remove the "control unit" (or what we used to call the lower valve body in the rest of the GM/Chrysler world) and somehow repair this problem. Words like "seized" mean more than "stuck" or "binding" -- seized indicates it might not EVER be right again. There was more than a sanding of parts in the pan so possibly some of it got into the valve body "brain". Automatic transmissions were the holy grail for us kids growing up -- the only item on the car we took to a "professional" since they had all kinds of tools. Then we started to tear into them and install improved logic "shift kits" and once in a while "manual valve" bodies. It's really not that bad unless you have to tear into the clutch packs and pumps -- then I'm in over my head (really just lacking the special tools, detailed manuals, and measurement devices).

Have you ever dropped a ZF "valve body" or "control unit"? Do springs go flying or check ***** scatter? This problem sounds like it might still be resolved with the tranny still in the car -- just a matter of getting another valve body or cleaning/fixing this one's primary regulator circuit. I wonder if it could "unstick" over time? Sometimes the "regulator" is a check ball, sometimes it is like a bullet in a barrel that is pushed yonder and hither by fluid pressure.

Thanks,
Tony

 

I imagine this section has something to do with it -- but no mention of the location of primary regulator. I guess we are supposed to have inate knowledge of the location. Here they use the term manual valve "operating mechanism" but don't tell you much more about it. There is another section that talks about a series of oil-control passages but no mention of what they do. inate knowledge?

 

Tony

Reverse gear interlock valve, control unit, primary regulator don’t appear in any of the PDF searches I have conducted on the CD.

ZF boxes are a fairly common box, at least in Australia, if I were you I would take a bit of time to speak with 3 or 4 transmission shops, more if you can spare the time, explain what is happening and see if you can get a consensus of opinion based on the history of the box as you know it.

Fluid pressure and electrics may also have a bearing.

I have never had to even think about pulling an auto box down because I’ve never had one fail, one of my sons who is a bit of chancer when it comes to risky undertakings and dabbling on the dark side recently had his box overhauled on a GM vehicle, I don't know if it was a ZF though, cost about $AUD1500 drive in drive out, even he wasn’t up to having a go himself.

Once in Thailand I watched over 3 - 4 days as a guy in shorts and sandals stripped one down, laid the parts out on newspaper spread on the floor in a pretty dirty workshop open to the elements on one side, he had a bit of trouble and had a few people come to have a look and give advice. I doubt there was any formal training for anyone involved but they got it back together, back into the vehicle and it worked, which amazed me because there are very few automatics on the road in Thailand so it wasn’t experience, though I’m not sure how well it worked but he said it was “OK Boss” when I asked him.

I'm sorry I can't be of more help, but keep us informed as you go.


Regards


Bill

 

Tony

I emailed you last night re some PDF files of the ZF auto trans, not sure if you received the email.

These are both the PARTS FILE and the REPAIR file, one is about 1.9 mb and the other is about 3.6 mb.

You will require Adobe reader 6 or 7 to read them they are pretty comprehensive and are suposed to cover ;90 to 94 RRC.

Let me know if you want me to send to you, it will be easier for me to email you direct rather than through this forum - for some reason I can't figure how to do it through the forum pages :-(

Regards

Bill