Patrol GQ Auto - RE4R03A - Missing Gears Diagnosis and Repair

Hi all,

As I mentioned in my 'Member's Ride' post a week or so ago (http://www.nissanpatrol.com.au/forum...-Roof-GQ-Wagon), my recently acquired GQ Safari has lost some gears in the auto transmission :(.

Having not had it for very long, nor having had an auto before, I had no idea what gears it had dropped. When I bought it the oil in the dipstick looked and smelt good so in a fit of vain hope I wondered whether it was 1st and 4th that I had lost, meaning it could be a solenoid in the valve body or simple electrical fault.

Out with the multimeter and service manual I checked all electrical components (solenoids, switches etc.) against specification. All was fine. Next, I drove around checkin the solenoid feed from the Transmission Control Unit (TCU) but again the electrical side was all behaving nicely to spec. Damn!

Next, I thought hmmmm....maybe its a stuck solenoid (more hope rather than anticipation!). So, I got some fresh ATF, filter kit and valve body gaskets and start to strip down the box with it still on the truck to rebuild the valve body, but found this in the pan.....

http://www.nissanpatrol.com.au/forum.../2012/07/9.jpg

And that signalled then end of my hopes it was minor electrical fault! lol

Looked to me at this point that some bands or clutches had been melted at some stage by overheating. It also smelled burned to all hell. Taking a peek up into the tranny sump I also notice that the reverse clutch brake band is burnt up and has no friction material left on it. This pretty much nails the problem as being a lack of 2nd and 4th rather than 1st and 4th (brake band is required by 2nd and 4th) so at least I know what I am dealing with.

So at this point I kind of know the job is going to be a little bigger than I thought. So the plan changes to this:

1 - Rebuild valve body and check all components.
2 - Remove transmission from Patrol.
3 - Strip transmission and check all parts for wear against the service manual.
4 - Order and replace the required components.
5 - Put box back in patrol.
6 - If it works again, put on a transmission cooler.
7 - Drive it for a bit.
8 - If it is still good get a Nomad valve body from Wholesale Automatics and do a DIY lock-up torque converter mod to leave me with a solid box.

Thats the plan anyway! I am going to be doing it all myself.....mainly just for the hell of it! I think I might be mad! I will update this thread as things pro/regress! :D

Good luck with that, big job ahead no doubt, look forward to updates

Started by rebuilding the valve body to standard spec. First job was to drop off the valve body from the AT. Here it is on my bench:

http://www.nissanpatrol.com.au/forum...2012/07/10.jpg

Was full of horrible black gunge which I presume is clutch or band material. Gaskets are very fragile as well. Cracking the valve body open is piece of cake:

http://www.nissanpatrol.com.au/forum...2012/07/11.jpg

The only things to be careful of are the orifice check valve, a little filter that nestles between one side of the valve body and the separator plate and a number of ball bearings (9?) that sit within the valve body assembly. The oil galleries within the valve body were in some places very gunged up so I set to work with degreaser and a toothbrush:

http://www.nissanpatrol.com.au/forum...2012/07/12.jpg

All the valves themselves were removed and packaged up in bags and envelopes so they didn't get lost. Getting the valves out and back in again is a fiddly process that needs some patience. I wouldn't say it was difficult though.

Re-assembly was the reverse of disassembly. Valves went back in one by one before I put new gaskets on between the upper and lower valve bodies and the separator plate. All the valves were liberally lubed with new ATF on reassembly.

The solenoids then got a full work out (clean down, resistance check with multimeter etc.) before being bolted back on the valve body along with the cable supports and hydraulic pipe protectors. Again plenty of ATF was put around the solenoids and seals to ensure all sealed well.

http://www.nissanpatrol.com.au/forum...2012/07/13.jpg

Given that I don't plan to put this back in until the rest of the rebuild is done, that pretty much signals the end of the valve body part of the job. All that is left is to put on the oil filter unit and bolt up the valve body and oil pan to the (yet to be rebuilt) box.

The rebuild of the valve body was pretty easy. I am reasonably confident it will work :eek:. I reckon if you have AT troubles and are lucky enough for it to be a valve body related problem then most could tackle this. It probably took me about 4-6 hours all up over two evenings.

So, with the valve body removed (and rebuilt) and the brake band the apparent culprit for the loss of 2nd and 4th, me and mate start to drop the box. First up we jack up the truck at the front, drop both prop shafts and disconnect all the electrical cables in the engine bay. I managed to borrow a trolley from work to lower the box on that is pretty much the same as a gearbox jack. It fits the bill except that it wont drop low enough to allow us to drag the box from under the truck. However, it gets it close enough to the ground that with cunning use of a series of chocks we managed to lower it manually the last 200mm (with a few heart in mouth moments!).

Daft things we forgot:

1 - The exhaust bracket on the side of the N/S gearbox mount.
2 - The four bolts connecting the torque converter to the flex plate (essentially the auto equivalent of the flywheel).

Once we remembered these last few bits dropping the box off was pretty easy. Our job was made harder by not being able to jack the truck up as high was we would have liked due to the roof in the garage at my rented townhouse. Definitely recommend a proper gearbox jack if you can get one.

Here is the truck jacked up with the makeshift gearbox jack in place:

http://www.nissanpatrol.com.au/forum...2012/07/14.jpg

Few hours later and the box is out and on the floor:

http://www.nissanpatrol.com.au/forum...2012/07/15.jpg

Took us most of a day (in between snags and beers) to drop the box. Next step is to strip the unit down and have look at the insides....

Hi mate, good luck.....been through this all before, not a job for the faint hearted, have you seen the internals of the auto boxes before?

I wonder if this will help save it from happening again.
http://www.ebay.com/itm/Nissan-RG4R0...-/200485056179

Quote:

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Originally Posted by 97_gq_lwb

I wonder if this will help save it from happening again.
http://www.ebay.com/itm/Nissan-RG4R0...-/200485056179

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yep they help :)

Quote:

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Originally Posted by NissanGQ4.2

Hi mate, good luck.....been through this all before, not a job for the faint hearted, have you seen the internals of the auto boxes before?

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Hi mate,

Not seen inside of one before today. In fact it was your thread I think that made me decide it was DIY all the way. I don't need the truck as daily driver so the time it takes to do it is no issue, so it will be steady steady time wise.

Started the disassembly this arvo, but realised I need a clutch spring compressor to remove the clutch packs. What did you do with yours? Did you buy a clutch spring compressor or make one?

Cheers,

Sam

Yep, one of these (http://www.ebay.com/itm/Nissan-RG4R0...-/200485056179), or the nomad valve body upgrade from Wholesale Automatics seem the go.

On the other hand I was under the impression that with overheating being a common problem, a nice big oil cooler might be good preventative medicine?

Made one up Sam, but if you can buy one I would buy one, was a pain to remove the clutch packs

Cheers

Todd

Quote:

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Originally Posted by waflyer

Yep, one of these (http://www.ebay.com/itm/Nissan-RG4R0...-/200485056179), or the nomad valve body upgrade from Wholesale Automatics seem the go.

On the other hand I was under the impression that with overheating being a common problem, a nice big oil cooler might be good preventative medicine?

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Overheating is an issue but more so when towing, I would install a temp gauge first before doing anything else so know what your temp is running at

G'day Sam,

Another Safari with auto..been there, done that?

I used to have these kind of problems with my auto gearbox, weak and very prone to overheating. Lost my brake band and all the clutches I guess, didn't shift in to 2nd and 4th range though. Sent it to auto shop for rebuild including the torque converter and fitted the stage 1 nomad valve body from W.A.T, installed 2 extra cooler in series with the factory cooler but still didn't helped much on the overheating issue especially with all the heavy bars, winch, slider and 35" rubber..bummer ay!

But it's all good now.. Replaced the torque converter with the later model, J4 t/c from a wrecker. My old t/c was F1 is smaller compared to the J4. The bell housing is also smaller (smooth bell housing) where as the J4 got ribbed bell housing. The only mod needed for me to fit the bigger t/c was the crossmember.

Anyway, good luck with the project mate. Im happy to share some thoughts on these auto..

Cheers,
Ade

Hi Ade,

Not ordered anything on the torque converter front yet. Smooth bell housing so presumably small TC here also. To swap for the later one I presume it is the bell housing, TC and also the crossmember you say that I need to get? Does the flex plate stay the same? I am looking to make a pretty solid tourer. Down the track I will probably be running a fair bit of weight (drawers, sliders, bars etc.) but on a moderate 2-3" lift on 33" rubber....

Is it really worth doing do you reckon?

Cheers,

Sam

Yup.. You need to get the later tc, bell housing and the flex plate mate. The crossmember can be modded, you just need to cut the holes both sides for the gearbox mounting studs and weld some sort of backing plate in there as the box will move about an inch rearward. It's a simple mod, no worry about that one mate..DIY stuff.

With bigger tc, nomad valve body and extra cooler I say it's really worth it mate. Hard on throttle my ATF temperature (tc outlet) never exceeded 120c on the steepest longest hill climb in the North Borneo! Lol..but it's reality mate. Around town on a hot tropical day here will see around 90c with all the heavy stuff on board.

There's even latest tc for this tranny, J6 I guess and W.A.T have them and it's in my wish list.

By the way mine is TD42 so I am not sure about the flex plate on TBs motor..

Check your drive shaft too see if it's still can slides in and out when the tranny being moved rearward. In my case no problem on both front and rear shafts..

Been a while so I thought I should update on progress with automatic gearbox rebuild. Following my last post I had the box out and on the driveway which was good. On to the scary part of taking it apart and seeing what was knackered.

First job was removal of the transfer:

http://www.nissanpatrol.com.au/forum...2012/08/13.jpg

Following that disassembly is pretty straightforward. Very little is pressed together so you basically unbolt the bellhousing and oil pump, pull out the oil pump and the gear assemblies all come out in sections. The worst job is without doubt getting some of the snap rings out. I was tight and wouldn't buy decent snap ring pliers so swore a lot at it and grazed my knuckles a few times. I massively suggest getting the proper pliers unless you want to look like a member of fight club!

The workshop manual is nice and easy to follow. There are lots of thrust bearings and thrust washers so as these came out i bagged and labelled them ready for reassembly following inspection for defects:

http://www.nissanpatrol.com.au/forum...2012/08/14.jpg

What you are left with is a pile of cogs, gears and clutches a bit like this:

http://www.nissanpatrol.com.au/forum...2012/08/15.jpg
http://www.nissanpatrol.com.au/forum...2012/08/16.jpg
http://www.nissanpatrol.com.au/forum...2012/08/17.jpg

Following removal of all the guts you are left with this:

http://www.nissanpatrol.com.au/forum...2012/08/18.jpg

So thats disassembly. Next part was inspecting the clutch packs and band for wear, which I will cover in my next post.

Next job was to take a look at the clutch packs and band to check for wear.

First off the band:

http://www.nissanpatrol.com.au/forum...2012/08/19.jpg

As you can see the brake band was completely stuffed. This should have been covered in friction material but instead all that was left was the metal part of the band. This had worn some deep scores in the surface of the reverse clutch housing as well which was frustrating. A slab of beer for the machinist at work and that was sorted out though.

Next the clutch packs. First off the snap rings retaining the clutch packs are removed and then the clutch and drive plates can be removed. This is one of the many clutch packs here:

http://www.nissanpatrol.com.au/forum...2012/08/20.jpg

The clutch plates and drive plates were inspected for wear. I was replacing all of the frictions (clutch plates) anyway but the steel drive plates needed to be checked for warping caused by overheating. The reverse clutch turned out to be hanging on by a thread with two of the three clutch plates worn to metal like this:

http://www.nissanpatrol.com.au/forum...2012/08/21.jpg

This is one that wasn't badly worn to give some perspective:

http://www.nissanpatrol.com.au/forum...2012/08/22.jpg

A couple of the drive plates were also warped so these were replaced as well:

http://www.nissanpatrol.com.au/forum...2012/08/23.jpg

So this basically told me why I had no 2nd or 4th and reverse was a bit dodgy (took a while to engage)! At the same time as replacing the friction pack and the odd drive plate a full seal kit was also put in. To do this a clutch spring compressor was required to remove the clutch pistons from each clutch assembly. I got an Am-Pro that cost $50 I started to take a look at the clutch packs. You use the spring compressor a bit like this:

http://www.nissanpatrol.com.au/forum...2012/08/24.jpg

By compressing the retaining plate towards the body of the clutch the snap ring stopping the clutch from falling apart can be removed. The spring compressor is then released leaving the springs underneath:

http://www.nissanpatrol.com.au/forum...2012/08/25.jpg

Next up was cleaning all parts and rebuilding.:p

thanks for the report, nice clear photos and text. I have so far been too la2y to clean up and take pickies, and get back into my projects - none of which have been as ambitious as a gear box rebuild :-)

Great write up mate, This write up was a lot better than mine ( which I never finished writing! ) this deserves to be made a sticky :)

Quote:

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Originally Posted by NissanGQ4.2

Great write up mate, This write up was a lot better than mine ( which I never finished writing! ) this deserves to be made a sticky :)

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Cheers mate! Planning on finishing off this thread over the next couple of evenings.

Your own was really the catalyst for me giving this a go. With a little luck this and yours together might inspire others to give this a crack, if they, like me, have a vehicle they use for fun, don't need as a daily and can spare some time to save some $$.

Next job as I said was the cleaning....definitely the worst part of the whole job. All the external surfaces were covered in 22 years of muck. The internals were covered in burnt on black friction material. Took ages to get all the bits clean and dried off:

http://www.nissanpatrol.com.au/forum...2012/08/26.jpg

Was also pretty amazing how fast the parts rusted (in minutes) following degreasing and drying if not oiled up with ATF fluid. Here is the pile after cleaning:

http://www.nissanpatrol.com.au/forum...2012/08/27.jpg

Next up the rebuild began in earnest starting with the oil pump. I basically just followed the order of the workshop manual but it is useful to do the oil pump first as you can test the two clutches towards the front of the box using it. After rebuilding each component I lubed them up with ATF pretty liberally and put the in plastic bags for storage since I was rebuilding the components over a number of evenings:

http://www.nissanpatrol.com.au/forum...2012/08/28.jpg

From a pile of clean/new parts assembly of the internal components is very quick. I also checked the amount of play in each clutch pack using a calliper versus the specs in the workshop manual. I guess this is important as if there is too much or too little play you might be in danger of undoing all your good work prematurely through accelerated wear. Lucky for me all tolerances were ok, however, if they are not you can get different width packing plates to account for any discrepancy. Here is one of the rebuilt clutch packs:

http://www.nissanpatrol.com.au/forum...2012/08/29.jpg

Once I had rebuilt all of the clutch packs, two in the front half of the gearbox, two in the back half and one on the casing, I started putting the box itself back together. This is a pretty simple process of reversing what you did on disassembly but with new seals and thrust washers. Each of the needle bearings were thoroughly cleaned with solvent and lubed up with petroleum jelly. The only slightly complicated part is checking the play in the gear assembly within the box. Using a calliper you measure the distance between the oil pump housing and the front gear set. This has to be within certain tolerances and it is adjusted using washers of different thicknesses. Luckily, again, the one that was originally in mine was to spec after the rebuild so no further change was necessary.

After a couple of hours of reassembly you end up with something like this:

http://www.nissanpatrol.com.au/forum...2012/08/30.jpg

...pretty much all ready to go back in!! ;)

Now to find out if it actually works after all that hard graft...

I have to say at this point I was nervous!!! This hopefully gives me an excuse for the fact that at this point in the rebuild the photographs pretty much dried up! However there was not a lot to see that others and this thread hasn't already covered but I will give a run-through anyway.

First job was to pickup and fit the reconditioned torque converter. This is a bit awkward as there is a key way in the oil pump that needs to engage correctly. Apparently if it isn't done correctly you can damage the oil pump beyond repair (as well as potentially your newly reconditioned torque converter). Fortunately there are more measurement specs in the workshop manual that allow you to check for certain if this keyway is correctly engaged. Now the gearbox was all ready for installation.

Me and a mate refitted the box in half a day or so using the same table jack as we used for removal three weeks or so before. This time though we only put the gearbox in leaving the refit of the transfer box for later. This made the whole package much lighter and easier to manoeuvre so I would definitely suggest this to others. We then used a series of chocks to get the gearbox bell-housing and the block parallel so the two would just slide together.....and they did!

After that we bolted up the flex plate to the torque converter using a bit of threadlock and then simply bolted all the bits back on including the transfer, driveshafts, oil cooler lines and coupled up all the wiring. Last job was refilling the gearbox with the 8-8.5l of fluid it required.

At this point I kept looking for things I had forgotten to avoid turning the key! :p But with nothing else left to do/check I put the key in it, gave it a crank and started it up. No nasty crunches was a good first sign so I was pleased with that! I was even more pleased after a minute or so of the rig running that when I dropped it in reverse it crept back and when I dropped it in drive it crept forward!!!!

So I had at least 2 gears: forward and reverse! Next up was a quick road test, which confirmed I had all forward gears and reverse working perfectly and the torque converted locked up at ~85kmh. Result!

So the gearbox has been in now for a couple of weeks and 500k's or so. It's a completely different vehicle now with smooth changes. Took it for a run up to Lancelin from Perth and back and it didn't miss a beat!

Would I do it again? Yes, for sure. Although I now have a lot of respect for the gearbox mechanics around (especially the auto fellas), I reckon when you have an old truck you should know it inside out and, if you have the time, fix it yourself if you can. I wouldn't say it was hard to do but it does take a lot of time. My girlfriend felt like a widow at times so be warned a project like this (especially a month after you bought the vehicle!) could cost you more than you bargain for! :p

I rebuilt mine to completely standard spec. I will be adding a temperature gauge in the very near future and probably a nomad valve body shortly after that but for now I am happy with having all the gears again! Hopefully will get many more k's out of the old truck yet!

way to go man,id be shitting myself if my trans shat itsself.
Nothing like that feeling of doing it yourself eh.
Very usefull post aswell,cheers for the effort of your write-up.

Awesome write up, and well done on the entire job.
I had the missing gears problem very soon after I'd paid for a complete rebuild to be done. Mine was an electrical problem, but certainly not easy to fix, as it would only play up intermittently. All good in the end though.

Thanks for that it is very infomative. Ive just bought a nomad valve body and a will set up a lock up switch and after reading that I think Ill add a cooler and gauge as well because I just bought a boat and will tow it with a GU 4.5 Auto

Quote:

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Originally Posted by tricksgonefishing

after reading that I think Ill add a cooler and gauge as well because I just bought a boat and will tow it with a GU 4.5 Auto

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I'd do the gauge first. Looking at Davies Craig coolers, they say anything over 93C is really bad for the ATF. If you don't get that hot, the factory cooler is big enough (though I don't like the way they go through the radiator).

Awesome work. Good to see its all working well. Great post.

Awesome work mate my auto recently let go so it getting pulled out now I've got a second hand auto lined up out of a efi model so it's got the big tc and ribbed bell housing but now since reading this iam thinking I will keep the old box and rebuild as a spare