'91 Navajo trans throwing fluid via overflow

[KGauger]

When I do alot of stopping and starting, my Navajo transmission overheats and starts spewing transmission fluid thru the overflow pipe. I have changed the transmission filter and fluid a couple of times. If I turn the truck off and I try to add transmission fluid when hot, it just spews the additional fluid out the overflow pipe. But I can add transmission fluid if the truck is running. After it left me stranded yesterday, I came back around 3 hours later. Without cranking the truck, the dipstick indicated the transmission was full. I added a quart of fluid and the truck didn't want to pull. With the truck running, I added another quart of fluid and it ran. The fluid doesn't seem to be circulating thru the transmission like it should. From reading, there may be 2 solenoids involved - one for 3-4 overdrive and one for the torque converter clutch. Presently it also doesn't want to shift correctly when cold. I can manually set 1st and 2nd but it doesn't want to shift into 3rd when in D until the transmission warms up - a couple of miles. Also having problems with OD. Thanks for any suggestions

 

[Glacier991]

I am guessing you have a very high mileage A4LD. Your spewing is obviously as you know, heat related. Heat comes from slipping frictions and/or an unlocked TC, although an unlocked TC alon should not cause your problem.

You have done well to replace the fluid and filter, but fluid properties are but a part of friction issues. I suspect your A4LD is just plain getting tired, and your line pressures and somewhat low, the frictions somewhat glazed etc.

While a VB rebuild would be a step in the right direction, along with a Sonnax high ratio boost valve and O-ring end plugs, I am reluctant to tell you this is your instant fix... in fact I strongly suspect you are in rebuild territory my friend.

If you want to exhaust every possibility here are the fixes I would try:

Replace the OD and Intermediate servos and O rings on servo caps (Ideally making the OD an upgraded ZC cap and servo and making the intermediate an AB version )
Replace both the TC and 3-4 solenoids
Replace the O-rings on the low reverse servo and replace the gasket on the top cap for it (D ring conversion would be good)
Add a Sonnax High Ratio Boost Valve
Add a Transgo Kit to the VB
Add Sonnax O-ring end plugs to the bore they make em for
renew your fluid
Replace your governor with a new one

No guarantees.

 

[KGauger]

Junkyard

Thanks for the information, Glacier. Unfortunately a rebuilt transmission is going to cost as much as the truck is worth. I have limited mechanical ability and I think I would only mess up trying to fix it myself. Looks like I will be heading for a junkyard and take a chance on a transmission. I know the transmission is overheating but don't understand why the fluid is collecting in the part of the transmission with the overflow pipe. It seems to me that something is clogged or not opening properly to let the fluid circulate properly. The incident the other day was a little more exciting than I wanted. The spewing transmission fluid was hitting a crossbar next to the tailpipe. And had caught fire. I had a gallon container of water in the truck and was able to put the fire out after a couple of minutes by throwing water from the container under the truck. No real damage but too close for comfort. I am adding a piece of plastic tubing to the overflow pipe so the transmission fluid will not hit the crossbar in case this happens again before I replace the transmission.

 

[Glacier991]

stock has an overflow pipe that daylighted near the bellhousing, maybe yours got removed or somehow torn off. Good luck.

 

[rinnels69]

Check-out "Green Leaf" for a used tranny. I got a 5R55W from an 04 Mountaineer with only 23K miles with a 12/12K warranty (parts and labor) shipped to my door (ok, the loading dock at work) for $1300...that included shipping! Took me and a friend on a lift about 14 hours to do the swap. Good luck on whatever you decide to do!

Mike