Transmission Overheating Help Please.

[hotqld]

I have a 2007 CRD Jeep Grand Cherokee wh lorado Quadra Trac 11. 102,000 klm.
Easy driving 15 klm 20 minutes the following warning came on:
"service 4WD system"
"esp bas on"

Then going up a hill 2 klm later no power and could not climb the hill had to stop.
Now the warnings in addition to the above:
"Transmission overheated"
" ETC warning light on"

Stopped waited 5 mins car would not engage in D felt like it stayed in N.

Waited another another 5 minutes and car moved off felt like 1st would not change into 2nd.

Drove home taking the jeep up to 50klm then coasting down to 10klm in nuetral for about 20 klm / 35 mins nursing it to get home.

Arrive home fans under bonnet are roaring 6pm.
So I reckon leave till morning when cool and check transmission oil levels and maybe take the sump off the transmission.

Any ideas what I may be in for?
Could the most ecomical repair is me take transmission out and drop it into a specialist gearbox repair company?

Any suggestions what to do? I want to do as much as I can but have no experiance with auto transmissions. import new gearbox from USA? Or hopefully I might just be out of oil?

The wife did remark last week it appeared to be staying in gears too long before shifting to a higher gear.

[fester]

Not sure on your issue but the result sounds as if the ECU has put the tranny in limp mode in relation to your lack of shifting and reduced speeds. The issue could be quite simple but I think the only way to find out would be to get it to the dealer and have the TCM (transmission control module) read for the applicable fault codes. You may be able to get your hands on a generic fault code reader but this will not read the specific fault in the TCM. The ECU will be throwing up a generic transmission fault code which generally doesn't give much clue.

There has been other discussion in the past on the service 4wd system warning but I don't recall what it was about. The overheating could be simply a lack of oil but generally the transmission doesn't consume oil so if that is the case there may be leak. The WG does not have a dipstick so checking the oil is not so simple, not sure if the WH gained the dipstick back. None of the Mercs with this gearbox have a dipstick either. To check you have to have the factory service tool or a copy and then you have to check it at correct temps. You could drop some or all the oil and look at the condition and see if it smells and looks burnt, you could then replace it with new stuff but you won't be sure of the level. The WG seesms to take about 3.5 litres in a general change. You can buy an aftermarket dipstick tool off Ebay. I tried to buy one from the Merc dealer and they won't/can't sell them.

So again I'm thinking your best start is to get the diagnostics read at the dealer. You can see what happens at a restart and you could disconnect the battery but it's likely only a short term reset. YOu cna also jump on one of the Merc forums toi get much more detailed info on issues with this box.

[Tiddy]

Hi Fester

I assume when you say this, your talking CRD's "The WG does not have a dipstick so checking the oil is not so simple"

tiddy

[fester]

Is there anything else worth considering .

Yes the subject vehicle is a CRD and all CRD's have the Merc 5 speed gearbox which does not have a dipstick. When first bought out MB was billing it as sealed for life but I think they soon found out that without changing the oil "life" had a fairly short meaning. However to date it has never been fitted with a dipstick.

[hotqld]

Thanks Guys for your help,
I drained the trannie oil and have about 3.5 ltrs. Same as what you mentioned for the WG. The previous owner changed the trannie oil himself.

When I refer to my service manual for the 3 ltr CRD it says 7.1 litres for a service and 9 ltrs for a rebuild. My oil suppliers lititure said I needed 9 ltrs as well, So appears it has been running on 40% of what it should have been.

We do have a dipstick thingie but they try to hide it.
see attached apparently they wont sell you a dip stick , but I used a stiff wire about a meter long and apperently they are on ebay.

Yesterday the jeep would not drive when on a really steep hill but when returned to flat it went into drive only 1st.

I reckon it is in limb mode, my code reader would not get it out and disconnecting the battery for 15 minutes hasnt worked either.
any other ideas?

Maybe when I fill the trannie tommorrow it might? , I had to wait for a trannie filter.

Comments / help very welcome

[turbomart]

Are there any signs of oil leakage around trans ? if not it may not have lost any unless prev owner filled to wrong amount/level.
Also be carefull of oil used, wrong oil can stuff these trannys.
Your problem does sound like low oil level ie works on flat ground but not on hills.
You may have to go to dealer or tranny specialist to erase fault codes.

[multihull]

Originally Posted by turbomart

Are there any signs of oil leakage around trans ? if not it may not have lost any unless the previous owner filled to wrong amount/level.
Also be careful of oil used, wrong oil can stuff these trannys.
Your problem does sound like low oil level ie works on flat ground but not on hills.
You may have to go to dealer or tranny specialist to erase fault codes.

I agree, check for an oil leak first. If there's no signs of a leak this is not the problem. The problem could be the last owner put the wrong oil in or not enough. When I changed my tranny oil at 100k I took the cap off the dip stick tube and pushed a length of gal wire down as a dip stick. I then marked the level and when it came to a refill I had the correct level. (this is now my official tranny dip stick) Also when you change tranny oil you should drop the pan and clean the magnet, change the filter as well as draining the torque converter. This holds a heap of oil too. This adds up to about the required amount but there is also oil left in the transmission cooler too.

Check your driver manual for the correct oil spec. It's a common oil that can be bought from Super Cheap and other similar discount suppliers.