Jackaroo Gearbox !!!!!!HELP!!!!!!

Submitted: Thursday, Jun 01, 2006 at 14:43
ThreadID: 34504 Views:11530 Replies:7 FollowUps:2
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I have 2000 SE 3.5L Auto Petrol
The car has just started gearbox flaring on occasions. Only appears to happen when it is warm
Flaring can occur when coasting into intersection in high gear and then putting foot on accelerator - Lots of noise but no gear change for a bit and then it goes in.
Sometimes happens going up thriough gears also.
Took it into local mechanic and of course I could not get it to happen when I tried to demonstrate.
He phoned someone who knows Jacks (dealer I suspect) in case the model has a habit of doing this type of thing.
Came back with $2500 - $3500 gearbox - No other possible cause.
Obviously I will need to get other opinion from somewhere.
Has anyone any experience of this type of thing?
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Reply By: Eza - Thursday, Jun 01, 2006 at 16:43

Thursday, Jun 01, 2006 at 16:43
this might sound really silly but i had a mate with a similar model jakaroo who was having similar problems kicking up and down gears etc generally playing up like two bob watch particularly into a longer drive, after several mechanics and a few backyard ones was told everything from a new gearbox to a new diff required, finally took it to holden dealership put it on the computer, wait for it, blocked fuel filter, gave him a generic one cost him $11. hasn't played up since!!
worth a try I say, it actually played up a little after changing the first filter, after replacing the second one has run like a charm for months now!
AnswerID: 176149

Reply By: WDR - Thursday, Jun 01, 2006 at 17:48

Thursday, Jun 01, 2006 at 17:48
That was my next call, I really hope something like that is the problem.

AnswerID: 176165

Reply By: Member - Bruce and Anne - Thursday, Jun 01, 2006 at 18:06

Thursday, Jun 01, 2006 at 18:06
My Isuzu MU Wizard (Holden Frontera) 3.1 turbo diesel auto could not work out what gear it was in, especially when you put the foot down. Had a service new filter and oil about $140 and now plant the foot and she will red line in the first three gears, if it has not had a sevice than that may be the problem or the electronics might need a re boot. Also check out one of the Jackaroo 4WD clubs on the web, they might have some info.
Cheers Bruce.
AnswerID: 176168

Reply By: Member - Stephen M (NSW) - Thursday, Jun 01, 2006 at 18:42

Thursday, Jun 01, 2006 at 18:42
Like EZA thought, this might sound stupid but our commodore (yeah I know not a 4by) was doing the same thing coming back from Lithgow one day great I thought problems already and only had 5 k on it. Took it to Holden told them what it was doing would flare then jump into gear turned out to be a dicky spark plug lead, put a complete new set on and no problem ever since now has 65 k on it. Said it was flaring cause computer was not getting correct info / Power from engine computer to transmission computer so tranni didnt know what to do.I presume yours is computer controlled as well. Just another thing to check first.Who would think that a stuffed lead would cause our transmission to play up but it did. Hope you get it fixed ok and its only a minor problem. Regards Steve M
AnswerID: 176175

Reply By: FZJ 80 - Thursday, Jun 01, 2006 at 19:40

Thursday, Jun 01, 2006 at 19:40

Heres the answer. The inhibitor switch! The inhibitor switch does 2 things
1. Inhibits start in all positions except park and nutural.
2. Tells the transmission computer what gear is selected.

Go for a drive . if the "D" in the inst cluster display is not lit up or intermittantly goes out the inhib sw is the most likely cause, try wiggling the selector.

This is common on 3.5l Jacks. A mate of mine had his fail with same symptoms plus a violently harsh downshift at times. His happened at around 70 000km.
The swiches are expensive - around $750 from memory.

Not a guarantee but very common and worth a look.

All the best
AnswerID: 176184

Reply By: ro-dah-o (WA) - Friday, Jun 02, 2006 at 00:09

Friday, Jun 02, 2006 at 00:09
If none of the other suggestions help, jump onto a yank site called www.planetisuzoo.com

These guys have the answer to anything and everything isuzu and are very quick to reply. Make sure you call your car the right one, as I they call jackeroos something different (trooper I think)

A few guys in (make that alot) in my 4wd club have jacks and have all sorts of probs because of the over abundance of sensors. From their experience, make sure you signal out all possible sensor /blockages etc before looking at the new tranny. And watch the mechanics, one of the guys paid $1600 for them to diagnose a oil sender switch!!! It took the mechanics that long to find the problem.

Good luck
AnswerID: 176259

Follow Up By: WDR - Friday, Jun 02, 2006 at 20:16

Friday, Jun 02, 2006 at 20:16
Thanks for all your help - here is the latest

Thanks for all the advice and suggestions - We took it to a GM dealer today and all they could offer was a $95 plug in to the computer to test the electronics - no mechanical info. They also admitted they know little about Jacks, only see about one a month for servicing - Interesting - This is a big GM dealer in Parramatta.
They then offered to give us the name and address of transmission specialist they use.

Went around there and what a difference - plugged some computer in immediately and established it was not electronic.
Offered to service it immediately which we agreed to.
In their opinion it had never had oil serviced or replaced, very small amount in it and that had the wrong smell. They then too off the sump and inspected things.
Filter was totally blocked
(Is this a part of the GM servicing program - the car has been serviced by GM since new?)
There is a magnet in the sump housing and it was covered in grey stuff METAL
Asked me if we were planning to sell it.
Offered (if need be) a rebuild for $2400 including parts and labour.
They replaced gasket, new filter, filled it with oil and set us on our way.
We are now waiting to see what happens over the next couple of days.

One interesting thing we noted - There is a magnet to collect shavings etc in the sump - Presumably it is expected that that will happen - My question is - Is that normal.
They also told us the car will tell us before it gives up - Either with warning light or further funny things like we have just experienced.
FollowupID: 432489

Reply By: ro-dah-o (WA) - Saturday, Jun 03, 2006 at 00:31

Saturday, Jun 03, 2006 at 00:31
thats good news.

Interesting about the GM servicing, any way you could get some form of compo from holden for not doing as they said they did??

Ive vowed never to visit a holden dealer again. Had a couple of situations where they said they fixed or replaced, but never actually did. Didnt find out that they had stripped both filler plugs on the gear box until I replaced the oil myself. not impressed.

Also had a holden dealer in NSW try to tell me a isuzu oil filter was going to cost $60!!!! That anoyed me, as the mechanic around the corner only charged $15!!!

But Im sure many people have had pleasant dealings with holden, from what I have heard none are related to 4wd tho
AnswerID: 176484

Follow Up By: Gerhardp1 - Saturday, Jun 03, 2006 at 10:10

Saturday, Jun 03, 2006 at 10:10
It's not the dealers fault that the transmission dopesn't get serviced, as the books say it's a "sealed for life" transmission. It has no dipstick and the procedure to check the oil levei is a bit of a pain.

Some argue that once you replace oil in a "sealed for life" unit, it will stuff it because, presumably, the clutches and gears have some sort of intelligence and will self destruct in this circumstance. Has to be cr@p, in my opinion.

My jack has 120,000k on it now and I have a tranny filter and gaskets ready to go in with new fluid. Haven't decided whether to take it somewhere or do it myself, since I don't trust that a service place will know how to fill it correctly and I'll have to check their work anyway. Don't want to be halfway to Bamaga with camper trailer on and a blown tranny due to not enough oil.

As pointed out above, the inhibitor switch can cause jerky changes. Why it does this is a mystery, but dirt ingress is a possible cause. Mine did this a couple of years ago so I took it to Barloworld who removed the switch, cleaned it and replaced it. It was much better but not right, as I still had an occasional jerky shift. So I pulled the switch off myself, split it open and checked inside. The main contacts are embedded in resin and the sliders are housed in recesses, so there is no possible way that they could misalign or bridge and short the wrong contact. But the process for installation onto the tranny is intricate, requiring a little pin to be inserted to align it, a bit like aligning a clutch. The position mine went back on was different by a few degrees, and there has been no problem from it since, so I can only assume that the dealer didn't know how to re-install it, or ignored the manual.

As others have mentioned, semmingly unrelated problems can cause flaring. I recently replaced the non-standard muffler with a standard one, which increased the backpressure again to approximate factory values. The result has been better changing from the Auto and better fuel economy than with the straight through muffler. Conclusion - the correct backpressure improves the computers ability to tune the engine which interacts with the powertrain control module like it should and improves gear changing.
FollowupID: 432575

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