Patrol GQ Auto - RE4R03A - Missing Gears Diagnosis and Repair

[NissanGQ4.2]

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?

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

[Ade]

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

[waflyer]

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

[Ade]

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.

[Ade]

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..

[Ade]

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..

[waflyer]

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:



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:



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





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



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

[waflyer]

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

First off the band:



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:



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:



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



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



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:



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:



Next up was cleaning all parts and rebuilding.

[Silver]

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 :-)

[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