Manual Gearbox leak

[deestingray]

Hey,

I have a 91 2.8TD MU with the normal 5 speed and it seems to be leaking oil from the top around the 4WD selector somewhere. It only leaks when I am on the highway and starts at around 105kph and gets progressively worse if I overtake and maintain any speed above this. The result is a lovely gearbox oil smell and oil spray all over the rear window and tailgate. Seems to be coming from the drivers side of the box as the inside of my rear wheel is usually coated after an hour or so. I have pulled the covers off from the inside and notice that there is a nylon block, but am wondering if anybody else has experienced this at all and if anybody has a fix?

[geeves]

Check the oil level in both the gearbox and transfer case. One will be overfull the other nearly empty. Bad news is this is an internal seal between the 2 that is a gearbox dismantle to fix. Leaveing it will kill the box
Good luck

[deestingray]

Oh joy!!!! Thanks for that great news Geeves, I will endeavour to do something soon. A mate of mine had to rebuild his box recently.......think he parted with about $2500. Is this a common occurence??

[Bruce]

I have another thread here about gear box leaking, on the next page, give it a read.
The leak at the top of the box has stopped. I started by putting Nulon stop leak in it but that did not work, had alook around and found STP engine stop leak (says rejuvenates seal and gaskets) and it was the gaskets that are leaking on mine. Still got a leak in the most rear gasket, between the box and transfer case so will put some stop leak in the trans case now.
But you must realize it can take some time to take up, also check all seals on drain and filling plugs.
I was quoted $1100 to fix and that garage taking box out and putting back in. Hope this is of some help.
Cheers Bruce.

[geeves]

Yes try a good quality leak stopper liquid first To do properly the box has to come out and thats 500 on its own. Once out it shouldnt take more than a couple of hours but at mechanics rates it hurts.
I used Nulon in mine and it worked well STP and Wynes also have a good reputation. If it fixes it its a cheap repair if it doesnt it only cost 12 bucks.
Check the levels regularly

[deestingray]

Hey Bruce,

That sounds like a better option, thanks for the suggestion. I see you are at Nanango, was it a local mechanic that quoted you that?? Just from the ums and aaahhs I get when I call around, seems not much is known about the Mysterious Utility. I will give that a crack first, just spent a couple of grand on it with new CV's, Shocks and Tires......
I have spoken to a mate of mine that suggested a different kind of fix that he had with his landcruiser on the seal between the transfer and the gearbox which involves a hose between the filler plugs, sounds pretty good to me, has anybody done this?

[geeves]

thats a cunning plan Unfortuanatly the filler plugs are at different hights as are the correct oil levels
Anouther way is just keep topping up the one that is low. It will leak sometimes out the breather of the high one though.

[deestingray]

Hmmmm, well that dents that idea, I will probably still go that option though as well as additives etc.....I don't like the idea of spending another grand right now as I am sure everybody will understand.

[Bruce]

Was quoted that price in Nanango.
Always ask for Rodeo parts, other wise they get confused.
Another fix also, for the gaskets leaking is to seal from the out side, using a product called DEVCON have it on order from local auto spared place, my old mechanic told me to fix this way and David Pig75 (he is the guru MU mech, his advise and help is the best I've had ;D) thinks it could work also.
My biggest worry is that I get oil over my exhaust, not a good look.
Cheers Bruce.

[deestingray]

Yeah I know what you mean, I get a bit of a coating too, will have to address that. I have heard of and used Devcon, it is an aluminium type compound isn't it? We used it to build up flogged out a/c compressor nose cones on nippon denso compressors. As for sealing, anything is worth a go I would say.
Bruce, Are you aware of a target rodeo year for these 91 MU's? Reason I ask is that the air filter for instance is the same as a 96 Rodeo.

[Bruce]

The model is TF I think, someone will know if Iam wrong. They are all the same except for panels from 92 to 1998. With the 2.8 the import has a belt driven OHC where the Rodeo is gear driven. With the 3.1 which we have I ask for Jackaroo parts 92 to 98 as well.
Cheers Bruce.

[geeves]

Not OHC It is belt driven but the cam is still in the block

[Bruce]

Got me there Alan! cam is still in the block! are we talking about the same thing, I thought that was the part under the head with the pistons, crank shaft, sump etc

[geeves]

only isuzu diesel with overhead cam is the 4jx1 and its very late replacement. All the others are overhead valve with push rods.
Only difference between the aussi 4jb1/4jg2 and the import 4jg2 and post 88 4jb1 is the drive to the cam and diesel pump. Some aussi 4jg2 engines are belt driven but not all.
You dont have to remove the timing belt when removeing the head because the cam is not in the head.

[deestingray]

Just a quick update, checked the oil levels in the gearbox and transfer case today, got about a litre out of the transfer and the gearbox needed about a litre and a half. Looks like it is leaking into the transfer but not externally except out from the shifter area when the transfer gets a bit full.
I have spoken to a few people about the hose idea with a positive reply. There is a kit type arrangement that you can buy from a number of places which includes the two filler plugs with nipples on the heads to attach a hose but also contains a one way valve so the oil cannot drain back. Just from what I have heard, the inertia created under braking is enough to move oil through the hose so I am probably going to give that a go.
Thanks for the answers and suggestions, I will keep an update going when I have done my mod.