GU wagon '05 3litre T/D ( auto problems ? )

[cossack]

Hi guys,
We've had our patrol for nearly 2 years now. All seems ok, accept when we engage 4wd and start general 4wding. Any incline and the vehicle starts to surge violently. By this i mean, loss of drive and momenium, then grabbing and driving. This continues until flatter ground etc. This places alot of strain on the running gear etc. but also, makes 4wding NO fun. Have taken the vehicle to Rowell & Searle ( all ok ? ), and nissan who ran a computer check ( all ok ? ). The vehicle has travelled 77,000 k's.
Any help would be GREATLY appreciated.
( Adelaide area )

[growler2058]

G'day mate welcome aboard good mob here full of useful info and advice. Someone will come along and advise soon mate. Good to see another south Ozzie here, we have a national forum meet up at Loveday 4wd adventures (Barmera) over Easter next year be good if you could make it

[cossack]

Any thoughts??????????

[Chaz]

G'day cossack,
The only thig that I can think of is low fluid level or possibly water in the fluid, but if you've had it checked by Rowell & Searle, that shouldn't be the case. The throttle can be very sensative in low range also and at times you can easily get into a Kangaroo hop when going up steep inclines, but that shouldn't cause you to loose drive. It may pay to check the breather hoses under the car just in front of the transmission crossmember because they often get ripped out or damaged and water can get into the trans and transfer through them.

[Yendor]

Could it be a problem with the auto locking hubs?????

Maybe try locking the hubs in manually?

[cossack]

Chaz, have looked at the lines and hoses, all seem ok.
Vendor, i'll have to check that idea out, i've heard that some of these hubs do have problems.
thanks guys,
What about looking at the torque converter? Are these auto boxes a throw away item? Or can you work on/adjust them etc.?
Any GOOD Mechanics in Adelaide that specialize in these boxes?

[Chaz]

I thought about the hubs too, but then thought it would still have rear wheel drive, so it can't be them. I have heard reports of the transfer case chain jumping, but then again, you would still have rear wheel drive and only loose the front.

The torque converter would make sense as would low trans fluid levels. Another thing that could cause this would be if the screen/filter in the transmission was blocked or partially blocked. Failing that, I would check the line pressure dropping resistor circuit and solenoid.

The fact that it only does it on an incline points directly to fluid level. Make sure that you check the level with the transmission warm and in reverse gear with the engine running.

I wouldn't say they are a throw away transmission. They can be serviced, rebuilt and improved, but most of the adjustments are done from factory and the servo's are self adjusting.

[Yendor]

Are you able to test it on a bitumen road, one with about the same angle of incline as when the problem occurs when 4wding.

If the problem occurs when in 2wd it would indicate a problem within the auto.

[cossack]

"I would check the line pressure dropping resistor circuit and solenoid", i'm starting to get out off my depth of expertise Chaz.
I just remembered when we had the GU dyno'd at Hi-tech, they did mention to have the trans looked at.
The car drives ok in normal driving, and pulling a camper trailer etc. seems to change when required.
Still might have to take it to the Pro's. Any thoughts on who specialises in auto trans for 4X4s in the Adelaide area?
Thanks guys.....

[Chaz]

"I would check the line pressure dropping resistor circuit and solenoid", i'm starting to get out off my depth of expertise Chaz.
I just remembered when we had the GU dyno'd at Hi-tech, they did mention to have the trans looked at.
The car drives ok in normal driving, and pulling a camper trailer etc. seems to change when required.
Still might have to take it to the Pro's. Any thoughts on who specialises in auto trans for 4X4s in the Adelaide area?
Thanks guys.....

Sorry, I'm not much help there. I have never had the need to go to a trans specialist. I use to buy parts from Rowell & Searle and ATP in Coglin Street, but never had any work done by them.

The line pressure dropping resistor is on the firewall, where the clutch master cylinder would be if it had a manual transmission. The resistor should measure close to 12 ohms and the voltage to it should vary with the throttle. Normally the line pressure increases with the throttle. If yours isn't increasing it will cause the transmission to slip and flare. Alternatively, the solenoid inside the transmission could be faulty and leaking which would give the same result. Some of us replace the resistor for one with much higher resistance to increase the line pressure and limit the amount of slipping in the transmission.

[cossack]

Vendor, we needed to drive up a small steep incline the other day with out 4wd engaged and found out that it still surges etc., but not as violently as when in 4wd. i still think its something to do with the auto.

[Yendor]

Well that narrow it down.

Sounds like you need to take it to an auto specialist and see what they think, I guessing they will connect and an oil pressure gauge and then get it to play up.

It funny, I was only just wondering yesterday how you were getting on with this problem.

Hope it an easy fix for you.

[cossack]

I've dropped off the patrol for repairs? They seem to think it has something to do with the "Lokka" diff lock on the front. They'll look at the chain on the transfer case etc. Maybe remove this locker, which they DON'T recommend?
I'm STILL not sure????

[cossack]

Finally have found the problem, transfer case bearing! Oil was BLACK etc. luckily no damage to the chain ( $1700 new chain ). fitted manual locking hubs and removed the lokka. The Lokka had been fitted without shimming, was out by a fare bit, and had caused additional problems etc. BE CAREFULL WHO INSTALLS YOUR LOKKA!