Nissan Patrol 4x4 (Africa)

Last weekend I towed a two ton trailer loaded to the brim with garden refuse and noticed after some time of heavy towing in traffic there was some flaring between gears one and two between about 2200 rpm and 2600 rpm. It also seems to only happen at around the same throttle position. At other revs it doesn't seem to happen or perhaps I just don't notice it. It flares about 200 rpm and drops into gear and seems to get worse the harder it is has worked.

I've since been able to replicate this a few times when it is really hot out. I need to drive like a maniac, presumably to heat things up thoroughly, before this will start to happen.

Considering the background of the car I fear the worst but hope there are some possibilities, read civilised possibilities, other than a gearbox replacement or rebuild that I should look into first.

Some things to consider.
1. The oil is fresh and filter is clean and new. Fluid level is fine. I replaced it all when I purchased the car.
2. Engine has been replaced. A history of abuse and poor maintenance was apparent at this point.
3. Gearbox oil was ugly when I got it. I didn't get a burnt smell, but I don't know what burnt ATF smells like. A number of oil changes (Matic J from Nissan before you get all excited) were made till it was clean and the filter is new.
4. The radiator is brand new and was replaced with the engine.
5. When the car is cold gear shifts are quick and smooth. Possibly the thinning of the oil causes problems when it heats up. Could also be valve body somewhere.

Any ideas?

seeing that you live in centurion...... take it to Gtech

Considering the symptons, i suspect it is tied to gearbox oil temperature.

Maybe consider adding a gearbox oil cooler?

I had the same thought Peter. The oil cooler on the Patrol is embarrassingly small. I phoned around for a radiator place in and around Centurion that will fit a larger oil cooler but no one seems to do oil coolers, just radiators. As soon as I can find a place a big puppy will be installed. I am worried that there is a bigger underlying problem. I get the impression these boxes either work or they're broken.

If no joy I will have to contact the professionals.

http://hot4cold.co.za/contact-us/

Universal Coolers in Centurion

Om te meet is om te weet...sit n temp sender op pyp voor en check eers reverse flow op die cooler en kyk of hy nie vol modder is na jou rus de winter trippie nie...ek het nog nooit olie temp problems met n 4.8 gehad nie

So I've been driving the Patrol on and off as and when it was necessary. The flaring doesn't seem to get worse or better. Radiator bypass has no effect. I don't think it is a cooling problem, but rather, and unfortunately, a gearbox problem.

Does anyone know of a specialist for these gearboxes that I can see for a diagnostic?

All-O-Matic in selby have rebuild sevices & specific kits for the Re5 box.

Ask for Braam.

I have a strange question regarding the auto box.

Is it at all possible that a bad fuel pump can affect the gear shifts?

The reason I ask is that I experienced improvement in gearbox shifting twice now. The first was when I had the unichip installed and dyno tuned. This is when it was picked up the fuel pump is bad and needed to be replaced. Dastek did what they could to 'compensate' for the fuel delivery problem. The net effect was an minor improvement in economy, performance gain and an improvement in the shifting from first to second. However, the problem was still there.

When I installed the new fuel pump a few weeks ago I bypassed the chip and installed the new fuel pump. Immediately I noticed an increase in performance, by a lot, and a significant improvement in fuel economy. After about one tank of fuel (I use about 3/4 of the main tank per week) I noticed the flaring had all but vanished. Another tank later and I cannot reproduce the flaring problem. It might just be that the stars have temporarily aligned and the problem is not manifesting, but for the moment it seems to be gone, even if I attempt to work the box very hard.

Is it at all possible that the fuel pump was involved or just something temporary?