Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[garyf]

Hi, Help / advice needed, sorry if it goes on a bit...

My Cherokee (1998 4ltr Auto) has developed a bad gearbox oil leak, I can't quite get my head round what is going on though so I thought I would put up a post to see if some body else has experienced the same problem and has an easy solution.

The gearbox is fine and has no leaks at all until you put it under load and it gets warm. Difficult to describe but if you are going along motorway at 70 MPH no problem, drive around town normally no problem but, go up a long drag ie.. up the valley road at Castleton, Derbyshire (about a 1 in 3 and 1/2 mile long max 20-25 MPH??)  and I will get about 1/2 to 3/4 of the way up and it will start to leak badly out of the bellhousing straight on to the front pipe thus resulting in clouds of smoke following you. The funny thing is get back on flat for a while going steady on the right foot and it appears to cool down a little and all is well again, well it is until the next long drag. I feel pretty sure if I put trailer on with SJ on it would have same problem if I was a bit heavy on acceleration??

Now for the really strange thing, did around 130 miles greenlaning both on and off road and it never caused me a problem while off road only in the stages getting in between the the lanes.

I would have thought that the gearbox would have got hot while doing the slow off road driving because there is very little air flow unlike when you are driving down the road.

The gearbox used about 2 litres throughout the day and I replenised at every available opertunity so it didn't run low. The gearbox is not overfull, it changes beautifully it locks up ok in gears, there is no slipping between the gears and the aux cooling fan comes on and off as normal.

I have a spare gearbox but I don't want to change it if there could be a problem with the cooling side ie.. radiator, filter blockages etc.. is this a known fault that some one has had in past???

It appears that if I could keep the gearbox slightly cooler then it would be fine, does anyone know what sort of temperature the gearbox oil should run at, I will rig up a temp gauge somehow if I get an answer on this.

Help and advice would be appreciated before I go head strong into changing gearbox for no reason.

Cheers

[greggmo]

i have seen this before with the autos but am not sure of the cause. i know mr o's xj used to do this so he might have a clue as to why. i am sure one of the guys can shed some light for ya.

[isle of man]

have you checked the oil cooler pipes are not crushed?







peter henry

[Mike Pavelin]

Stolen from Jeepclub.........(read from bottom up.

 
cherokee automatic gearbox overheating (newest first)
Tim & Ruth Gray, 1st Oct 2007 12:17  Quote  Reply  
Hi All
Cherokee is back with me and seems to be okay, a recon torque converter has been fitted and two new clutch packs in the gearbox.
Just need a decent weekend to get the caravan out and find a nice hill to drive up and see what occurs.
Tim & Ruth Gray, 25th Aug 2007 00:06  Quote  Reply  
The gear oil has been expelled via the breather, the box is out at the moment apparently the torque coverter is the main culprit and the clutches used bt 2nd gear are worn. Hope to get the cherokee back on tuesday or wednesday next week with a dent in my wallet.  
Tim & Ruth Gray, 27th Jul 2007 18:38  Quote  Reply  
I shall get it on a ramp on monday and check exactly where the oil has come out from, the breather sounds a distinct possibility.
Unfortunately for me I am off again the following week with the caravan.
Any body know where thd special tool for doing the ball joints can be bought from as these are knocking a bit?
Will keep you posted and thanks for help.
Vince Nicholas, 25th Jul 2007 19:40  Quote  Reply  
Are you sure its overheating. My '96 XJ showed very similar symptons after high speed motorway journeys. Tranny fluid sprayed the exhaust and created a veritable smokescreen behind me. I thought it was overfill at first but it kept happening. Dealership gave up on me so I took it to a local automatic transmission specialist. Seal to the torque converter was leaking at high temp. Replaced seal never happened again. BTW that was at around 60K
Robert Wright, 25th Jul 2007 17:54  Quote  Reply  
Checking my owners manual today, the level should be checked when the box is at working temp ie 77 deg C. If the level is checked at ambient temp, the book says the level should be at the "add" mark at 24 deg C. Level checks should be done with engine running.

Rob
Mike Pavelin, 25th Jul 2007 15:24  Quote  Reply  Edit
The AW4 transmission in the 4.0XJ is virtually indestructable, and at 50000 miles should be fine. A few thing spring to mind. Firstly, are you sure it's overheating? Check the fluid for signs of burning, it should be sweet smelling and a cherry red colour. If it's brown and smells horrible, change it and coninue to look for a cause for overheating. If the fluid was changed recently, is it the right stuff. You need good old fashioned Dexron II.
If there's no sign of burnt fluid, it could be that the transmission is overfilled (but you've fixed that) or that the transmission breather is obstructed. If you still think it's overheating, check the cooler and radiator fins are free from obstructions. You could also consider taking it to a transmission specialist and having it flushed out (will include coolers) and checked over.
There are no adjustments on an AW4, it uses multi plate clutches instead of brake bands, so will automatically compensate for wear. Unles the transmission is slipping, it is unlikely to be faulty.
Nick & Trish Edwards, 25th Jul 2007 12:20  Quote  Reply  
I've had a search around too, and also can't find the post.  I guess it might have been on another forum, but I've checked those too, and can't find it either - sorry.

I don't know if the adjustment of the belts in the auto transmission might have an effect on the oil temperature.  It's worth asking the question, but I can't offer any more advice, I'm afraid.
Tim & Ruth Gray, 25th Jul 2007 11:39  Quote  Reply  
Hi Thanks for all the response.
I did not realise that there was a cooler in the radidator as well as the small one in front of the air con condenser so thanks for that info.
I tend to use my jeep in full time 4 wd in the rain after sliding around a roundabout sideways the other day.
I have been experimenting a bit with the caravan and auto box this time i tended to leave it in gear 3 as it it is quite happy unless i am a nice long flat bit of road then i slip it back into d.  
I am wondering if the cooler in the rad is blocked or flow is restricted, they are not the best method of cooling oil in my opionion.
Just wondering if it is worthwhile investing in a bigger cooler to stick up in front as my probelm seems worse when the weather is hot, before i have the gerabox out, my auto specialist is talking about poor torque converter which sounds expensive.
Any futher views appreciated.
I have tried to search for other auto box problems but not found anything yet.
Nick & Trish Edwards, 24th Jul 2007 19:48  Quote  Reply  
My understanding (gleaned from when I had transmission fluid leaking from one of the pipes to the radiator), is that the pipework goes from the auto transmission to the main radiator, comes out of the main radiator to the small auxillary cooler, and then back to the auto box.

Hopefully Dr Mike will pick up on this, and tell it like it really is.
 
Gary Cottrell, 24th Jul 2007 19:10  Quote  Reply  
I always get confused with the radiator set up, as far as know (which can be written on a stamp) the Cherokee has the front little rad as the oil cooler with the large rad set up being the air con rad with the engine rad behind that.  
Gary Cottrell, 24th Jul 2007 19:05  Quote  Reply  
Nick & Trish Edwards said:
Sorry, just seen Gary's post re Full-Time 4x4.  We must have been replying at the same time.
I saw you log on so i had to hurried up with the typing
Craig Foster, 24th Jul 2007 19:02  Quote  Reply  
when you are going uphill do you keep it in "drive" or do you put it into 3rd.
dont know if that may help.

i can remember that you use a different grade oil in your diff!

Fozzie!
Nick & Trish Edwards, 24th Jul 2007 18:56  Quote  Reply  
Full-Time 4x4 is specifically designed to be used on-road at all times, so no problems there.  It's the high and low ratio Part-Time 4x4 which shouldn't be used on tarmac.  I'd be inclined to tow in Full-Time 4x4 anyway - less tractive load on each wheel.

As far as the cooler goes, I think the small one that you refer to is an auxillary cooler, and there is a larger one as part of the main radiator too - no doubt someone else will be able to confirm if that is the case. I seem to remember someone else having a similar problem, but I can't remember how it was resolved.  It might be worth searching through older posts to see if you can find it.

I guess it might be worth checking the usual suspects - mud etc in the radiator fins or auxillary fan not cutting in correctly.

Sorry, just seen Gary's post re Full-Time 4x4.  We must have been replying at the same time.
Gary Cottrell, 24th Jul 2007 18:50  Quote  Reply  
Paul Humphrey said:
I am no expert here, but the problem maybe down to being in full time 4 wheel drive. As I understand it they should only be driven in  4X4 mode off road.

I am sure someone should be along sson to confirm this.
Sorry Paul you are wrong ...

As Tim has the 4lt Auto Cherokee he can quite happily drive in either 2wd or 4wd (full time) on the roads.  4wd (part time) and 4wd (low) is for off road use, or for short periods where the road conditions are poor like in DEEP snow or on unsurfaced  dirt roads that have a loose surface.

2.5lt cherokees only have 4wd (part time) so can only drive on the roads in 2wd or again use the 4wd (part time) for short periods where the road conditions are poor like in DEEP snow or on unsurfaced  dirt roads that have a loose surface.

In my opinion though, you should only need to use 4wd (part time) or even low on the roads as a last resort.

Regards,
Gary.
Paul Humphrey, 24th Jul 2007 18:31  Quote  Reply  
I am no expert here, but the problem maybe down to being in full time 4 wheel drive. As I understand it they should only be driven in  4X4 mode off road.

I am sure someone should be along sson to confirm this.
Tim & Ruth Gray, 24th Jul 2007 18:01  Quote  Reply  
Hi all
I am sure soemone can help with this, i have a 1996 cherokee 4 litre auto.
I am having a problem with the auto box overheating when towing my 1000kg cararvan. The Jeep has a smallish cooler in the front of the air con condenser. I usually drive about 70 to 80 miles of mixed driving then come to a hill and the gearbox throws oil onto the exhaust and nicely deposits it on the front of my white caravan.  The first time this happaned my local auto box specialist found that the box was overfull as the last person to fill it did not fit the dipstick properly. Do i need a larger cooler for the box or shall i get another mortgage to have the box stripped and rebuilt?
Incidentally the jeep has only got 50,000 miles and has a full history.
When i drove away on friday night i did not have a problem although the weather was raining therefore cooler and i had it in full time 4 wheel drive.
Any advice welcome fellow jeep lovers.  
Displaying 1st - 16th of 16

[tedthefed]

Not sure if i missed it in the previous slot, but i was looseing oil from the rear main seal . Not quiet that much but enough to blacken my drive..

[Mick O]

i have seen this before with the autos but am not sure of the cause. i know mr o's xj used to do this so he might have a clue as to why. i am sure one of the guys can shed some light for ya.

No mate, it wasn't my XJ, it was KD's.

Was so bad it nearly caught fire on the M5

[Dave69]

hot oil goes thinner, rubber seals get plyable when hot, which could be a contributing factor with a leak going up a hill.

going up a lon hill will exert more strain and heat on a car especially when towing. over a period of time everything will be cooked hence people add additional oil/transmission coolers to certain vehicles so to reduce the heat in gearboxes.

green laning albeit hecktick at times will not creat the same kind of heat generation, what heat is made cools down and stabalises where as a towing or long hills is a constant heat increase until the load is taken off (flat or downhill part).

a 1 in 3 for 1.2 a mile is a typical trailor test for engine cooling. set a vehicle dyno and apply full load with a calculated resistance and see how long it takes to heat up and stabalise and watch the effect of the cooling fan if any

not a direct answer but might clear a few things

[garyf]

Had a look at the weekend to check pipes for damage, rad for blockages etc, couldn't find anything so went a little deeper and removed the flywheel cover to make sure it was definately coming from inside the bellhousing and yes it is so it must be coming from the torque converter seal, I still can't get my head round why it doesn't drop even a little bit in normal use.

What I did find but not sure if its relevant was that the torque converter to flywheel bolts, 3 out of the 4 bolts were loose, difficult to say but they were well over one full turn from being, tight they are quite a course thread (not sure of thread pitch but looks like it could be close to 1mm),  and my thoughts are that possibly the thing could possibly start to move, thus allowing the torque converter shaft not to rotate centrally under severe load thus allowing the oil seal to leak.  

can I have your thoughts please

cheers

[Dave69]

could you get a spanner inside to tighten them back up ?

[garyf]

Yeh done that Dave with a blooming long spanner so they are blinking tight and they won't come loose again,problem is there ain't no significant hills to try and break it near where I live so just looking for peoles thoughts whether they think it could cause it or have people seen it happen before

Cheers

[Dave69]

a torque convertor is just an oil clutch assembly. which is a sealed unit normally. the bolts just hold it onto the flywheel. with them being loose i'm surprised you didn't have any drive issues. i wouldn't have expected this to cure the leak unless the torque converotr is failing and leaking out of the input shaft.

[garyf]

yeh I agree exept they were only loose so once the slack was taken up on the bolts the drive was still there

I was just hoping somebody would tell me yes it is possible that your Converter can 'wobble' around 'eccentrically' with the bolts being loose and cause oil to leak out of the point your talking about, but I guess your thoughts are that not really possible hey???

[Mike Pavelin]

The bolts do help to suport the converter so it is possible I guess.

[garyf]

mike, there the sort of answers i'm looking for.

I am going to put trailer on it at the wekend and take it for a blast down motorway to see if I can get it to do it,