96 Gr Caravan Transmission Leak


RIP
03-15-2004, 02:07 AM
I own a 96 Gr Caravan with 138K miles. The transmission is working fine except I keep finding fluid on top of the transmission case trapped in the grid molded in the case. Eventually it overflows and drips on the pavement. It has coated the bottom of the van and covers the back door as I'm driving. I've cleaned the case off and tried to trace it but couldn't find the source. I've changed the filter/fluid but that didn't help. No leaks at the cooling lines. Is there a breather port or seal I'm missing on inspection? Help! I am adding a quart every 3000 miles. Ryan

RexNfx400
03-15-2004, 10:14 PM
Quick question.
Any fluid coming out between transmission and engine down by the inspection cover?

kitfox
03-31-2004, 04:15 PM
I've got a transaxle leak that I'm trying to chase down. I've been seen drips coming off the bottom of the bellhousing, right underneath the flexplate. I was thinking that meant its the front pump/input shaft seal. However, when I pulled off the cover down there where I could see the bottom third of the flexplate, it looked pretty dry. I was expecting that if the front pump was leaking then that plate would have oil on it. Pokintg around a little more, I found a small puddle of oil on the top rear of the transaxle case, just above where the passenger side halfshaft plugs in, by some ribbing on top of the case. Is there someplace on the top of the case where it could be leaking and then just running down the trans case? It's pretty hard to see around under there due to the cramped quarters and I hate to pull the transaxle only to find there's some small fitting that I can fix while it's still in the van.
This sounds pretty similar to the gentleman's post above. Ever find the source of your leak?

RexNfx400
03-31-2004, 07:11 PM
You won't see the fluid on the flex plate. It lays on the bottom of the tranny case inside there. Also the fluid you see on top of the case is from the pump. This is how it happens. There is a big O-ring that seals the pump to the transmission case. This O-ring gets hard from old age, heat cycles, whatever. Then as the fluid leaks through it, the the spinning torque converter will sling the fluid up and through the crankshaft position sensor. This is where the fluid laying on top of the tranny case comes from.

Thats as long as the differential spider pin isn't eating away at the case. You then should have a very large leak from the pump area. Not just some drips.

The pump needs to come off for a complete seal job and new bushing also.

Stay cool

RIP
03-31-2004, 11:26 PM
I've got a hunch I know the answer but, does the transmission have to be removed to pull out the pump and replace the pump seal? Thanks for the responses. Ryan

RexNfx400
04-01-2004, 01:02 AM
Transmission does need to be removed to reseal the complete pump assembly. The torque converter needs to be inspected carefully for bushing damage also.

kitfox
04-01-2004, 09:37 AM
Rex, thanks for your replies. You confirmed my suspicions. After posting last night I went out and looked around the backside of the case with a mirror and found the crank sensor. Started to put two and two together after that.

Quick questions: you mentioned checking the bushing for damage. Forgive my ignorance 'cause I haven't had one of these apart before, but does this bushing support the one end of the torque convertor? Is it a brass bushing? How hard is it to replace and can I obtain a new one from the dealer?
I already obtained a front pump seal 'kit' from my local dealer in anticipation of this, but I haven't opened up the kit yet. Is there anything else I'll need outside of that kit to do the job (assuming no case damage like you mentioned)? Anything else I should do while I have the transaxle out of the van?

As long I monitor the fluid level in the transaxle is there any reason I can 't drive it for a couple more weeks before tearing it apart?

Thanks for all your help.

RexNfx400
04-01-2004, 11:50 AM
The bushing is bronze. Its should be ok. It centers the converter into the pump. So just check the converter hub for smoothness. If smooth, then all is ok with bushing and converter. Also you'll need a slide hammer to pull pump. You need to hold input shaft in place while the pump is pulled from trans. Otherwise the input drum will come out. Then if the input drum is not all the way in when the pump is bolted back to trans. You will crush the friction plates. The input shaft has to turn freely once the pump is bolted back together.

It can get complicated real quick and things can get really messed up so be carefull.

Keep the fluid level in safe area and you can drive it till whenever.

Post if you have trouble...

And don't let the engine hang against phenolic power steering pully or that will be added to your list.

kitfox
04-01-2004, 12:57 PM
Hey RexNfx, thanks for the tips, really appreciate that. I will dive into this in a couple weeks. I'm sure I'll be asking more questions then.

Glad I found this forum - it's a great thing.

capoeta
04-05-2004, 08:34 AM
sorry for highjacking thread, but this seems to related to the issue I am having with a leak in my 95 caravan AOD tranny.

I had a slight leak in tranny that turned worst in a 2 month period. Bad enough to loose 2 quarts in less then 5 miles.
I removed transmission and just replaced the seals for the half-shafts and the seal behind the torque converter. I thought this would cure my problem, but tranny fluid is still leaking from the exact same place as previously, coming out of bellhousing through inspection plate and from above the bellhousing where the "sensor" is at. It's obvious that I missed something and from the posts above it seems that I needed to remove the pump assembly completely to fix the leak? can anyone confirm this?

Also, I believe that due to the original leak the torque converter is malfunctionning. When I bring the vehicle to a complete stop, the vehicle feels like it is surging forward, as if the torque converter was not dissengaging when idle. Also, when I tried to fill the converter with fluid prior to installation, it filled very, very slow. I could not even get one quart of fluid into it.
If I replace the converter, is there a "break-in" procedure or anything I need to do in the beginning.

Lastly, this would not occur before I brought down the tranny, but now ever since I installed the tranny back it seems to lock in 2nd gear once the tranny is at operating temperature. While still cold, it will drive fine, although when it is going from 2nd to 3rd it does try and occasionally will start slipping as if I had it in neutral. This happens especially if I ease into 3rd, but if I accelarate aggresively it will go from 2nd to 3rd a little suddenly (with a slight kick), but it will not slip.

sorry for the long post, but hopefully someone can help. thanks in advance

PS: I am indeed using ATF+3

RexNfx400
04-05-2004, 02:20 PM
Yes, the leak comes from the seals that are between the pump and the transmission case. One is a gasket, the other is a square-cut rubber seal. Also if the differntial is coming apart it will rub on case next to pump and leak. There is a break-in period for the (rebuilt/new)converter. It has to be done with a snan tool.

The other slips and things you desribe are too complicated to diagnose online. Probably your best bet would be a reputable transmission shop. They need to monitor data, codes, and CVI index on clutch packs. Maybe one other possiblity...If you changed your filter at the same time. Maybe the filter seal got torn so you have air in the system(Aeration). The lock-up clutch can do weird things when air is in the system.

Stay cool

capoeta
04-05-2004, 03:36 PM
thanks for the immediate answer.

I guess the tranny is coming back down again.... oh well. my mistake will hopefully help others going through the same thing.

on a side note: the slipping. I was able to keep the tranny from jumping gears by manually shifting.

stop.
L
3
D

It does not jump from 3 to 2nd anymore doing it that way, but I know that something is obviously not working right. It did not jump gears (limp mode) before so it must be something I did when I took it off. I did replace the filter, so perhaps I do have air in the system.

One last question before I go through this again... Should the torque converter accept and/or fill-up with fluid easily?

I'll post my results for the benefit of readers.

kitfox
04-20-2004, 09:15 PM
Well, I went on vacation with my van, blew a ton of fluid out from around the front pump and vowed to pull if when I got home.
This I promptly did, which was such a joy seeing as how there is soooooo much room to pull the trans out (yeah right!). Anyway, I found the large diameter square cross-section oring was very dry and cracked in numerous places. This was no doubt the cause of my leaking. I elected to also replace the seal for the converter, as well as both halfshaft seals. Pulling the front pump/cover off was not bad at all - as a matter of fact it came off very easily. There were some gaskets that came with the front pump seal kit which go on the input shaft. I figured since I had 'em I should go ahead and put them on. This is where things got complicated pretty quickly. I had to pull the input shaft and front clutch drum out to remove this shaft and replace the gaskets. That was not really all that bad. However, when I put it back in and bolted the front pump/cover back on I wasn't paying attention and I bent one of the friction plates. It was late, I and my helper were very tired and I should've known better. After sleeping on it we both agreed that something didn't feel right when bolting on the pump. We pulled it back apart and found the bent friction disc. Fortunately that was only ~$8 from the dealer. Anyway, I am putting it all back together now and want to make sure it all goes back together correctly. To that end, I am going to lay the transmission down on its pan when I put the shaft and clutch pack back in this time (instead of standing up on end). I think that will make it easier to get everything lined back up. I am a little scared to think that what else I might have missed in my late-night tranny session, so I was wondering does anybody have a blowup-schematic of the trans that they could send me? I have looked all over the libraries in my area and can't find a manual that covers this trans anywhere. I'd really like to get it back together this week if possible, so if anyone has a diagram or schematic they could send me I'd really appreciate it, thanks.

RexNfx400
04-20-2004, 10:32 PM
Its a good thing you didn't try to run that tranny. You would of been buying a whole lot of hard parts. About $500 worth. And a big contaiminated mess to go with it. Very good move. :)

There are friction plates that can get bent in the case, though not usuall. I'm sure it was a reverse plate in the top if the input drum. But make sure none are bent in case. You have to pull the reverse hub and front planet to really be sure.

When putting it back together:

Pull the Turbine Speed Sensor(TSS) or some peeps call it a input speed sensor. Thats the sensor right above the solenoid pak.

When you install the input drum, the exciter ring should just about be center while your looking into the TSS bore. Its never perfect center but real close. Make sure its center before you even install pump.

Sorry, I'm not able to hand out copywritten materials as all the companies that make my manuals forbid this.

You could have a local tranny shop order you a manual from ATSG(Automatic Transmission Service Group). Maybe about $40 or something. Its a real good manual. Theres an update manual also if you want, but you don't really need that one.

Good luck!!

RIP
10-14-2005, 10:46 PM
Just to end the reason for this thread - a new front pump/seal and bearing kit fixed the leak. That and $688.

ecfune
02-01-2008, 06:14 PM
Thanks for the post. I also have a problem with my '96 Grand Caravan. I should have read these posts before fixing my problem. I have replaced the front pump seal twice (where torque coverter shaft goes in) and it is still leaking. I have to wait until it warms to take the transmission down again to replace the O-ring and other seals. Hope I can follow your instructions to get it fixed. Thank you.

darlenestar
03-04-2012, 09:32 PM
Hello RIP,

Came across this old post. My 1996 GC 3.8 is leaking transmission fluid and going up the rear door, as well as, some fluid in the case upper grids. The problem has not been diagnosed as of yet but does sound similar to the one posted above. Did you perform the diagnosis and repair for $688 or was that all done at a shop?

Thank you for time.

Darlene

RIP
03-04-2012, 09:51 PM
Hello RIP,

Came across this old post. My 1996 GC 3.8 is leaking transmission fluid and going up the rear door, as well as, some fluid in the case upper grids. The problem has not been diagnosed as of yet but does sound similar to the one posted above. Did you perform the diagnosis and repair for $688 or was that all done at a shop?

Thank you for time.

Darlene

Wow. Talk about a ghost from the past. This might have been the first thread I posted on this forum - 8 years ago. Good Lord.

No, that was one of the few things I haven't done myself over the years. As I recall I poked around the web to get an idea of what it could be and a ball park cost to fix it. I then went down and talked it over at my local shop. They agreed it was probably the front pump seal but couldn't be sure till they tore into it. They removed the tranny, took it to a well known rebuilder in the area that replaced the parts, then the shop reinstalled it. Turned out it was a common problem and they used an available kit to fix it. The rebuilder said other than the seal the tranny looked new on the inside so only had to change the seal and the bushing that came in the kit. Oh and RexNfx400 was spot on.

ecfune
03-05-2012, 10:13 PM
It seems like we have a similar problem with the transmission leak. I replaced the shaft oil seal twice and it still leaked. I noticed that the cam sensor was wet also. I ended up replacing the front pump seal (big o-ring and other stuff) which I got from the dealership for about $14. It was not hard to do at all. I had to pull the tranny out of the housing and replaced the seal and the problem was solved.

darlenestar
03-06-2012, 01:01 AM
Thank you RIP and ecfune for the quick responses. It does sound like the possible answer to my problem since it was a known common problem. Will have it diagnosed when possible and keep the tranny fluid level full in the meantime. Need to read up on tranny removal/repair. Not sure if it would be feasible for a minor shade tree mechanic who has no fwd transmission experience. The van has 110k miles and some other issues. I don't need a transmission repair bill that would exceed the vehicle value ratio.

ecfune
03-06-2012, 07:08 AM
Darlenestar - taking the transmission out is not too hard. If you are a shade tree mechanic, put the front of the van on jackstands and bring down the transmission with a floor jack with the help of a second person. It is easier with a transmission jack but if you do not have it, a floor jack will do. Just be careful.

ecfune
03-06-2012, 08:02 PM
I enclosed a picture of the transmission fluid pooling on top of the transmission. The fluid leaked out of the crankshaft position sensor opening. The other picture is of the bell housing and the front of the transmission pump. The big o-ring was deteriorated and allowed the fluid to leak out. It was not coming out of the shaft like what the picture is showing. Hope this helps.

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