A4LD - Vacuum Modulator

[wreining3]

I just finished removing the transmission from my 92 explorer. When I pulled the vacuum line off of the modulator I was surprised to find that it was full of transmission fluid. Would this caise the transmission to fail, or was it just a side effect of the failure? Just curious as I need to replace the transmission anyway.

I really appreciate all of the information that I have found here. Great Site for explorer information. After reading about the remote filter setup, I will probably install a remote filter when I install the next transmission.

Thanks,

Wayne

 

[Howard]

The only way ATF can get in that pipe is if the diaphragm inside the modulator has failed. So you need a new one.

What was wrong with your transmission?

 

[wreining3]

I would occasionaly have problems with it shifting when it was cold. The overdrive had quit working. There was no noticeable braking effect when it was in low or second.

The last time that I drove it I was going up a hill and it felt like something gave out. I was able to get it home and could still move it around in the yard.

The transmission would move the explorer, but I could feel it slipping, it required more throttle pressure to get it to move in both forward and reverse. It had 99,000 miles on it when I bought it (not sure if the tranny had been replaced or not) and I drove it about 140,000 more. I didn't have access to a transmission pressure guage so I'm not sure if it was caused by low fluid pressure or not.

 

[TPLYNCH]

The modulator being bad will cause many of the problems you described w/your tranny. Also, the low reverse servo's goa, and they have been upgraded. Search for Low Reverse Servo, or for member OperaHouse and read what he has posted about the AL4D and the above items. You MAY NOT need a complete rebuild.....

 

[Opera House]

Thinking of rebuilding it yourself?

You've done the hardest part already, removing it. Most of the problems sound like they could have been solved without removing it. Remove the pan and see if there is any metal in it. It does sound like you might have snapped something in the OD section. These parts are cheap and easy to get at.

 

[wreining3]

There was a lot of sludge, that I assume was clutch material in the pan. Didn't find any large metal chunks but, could see specks of silver in the fluid that could be metal.

My pan doesn't seem to have a magnet in it. I'm thinking of installing one. I am also considering installing a transmission drain plug to ease fluid changes. Although I'm not sure if there is room at the deepest part of the pan. I don't want to restrict the flow to the filter. Anyone else have experience with this?

Wayne

 

[Opera House]

Could be worse

I once found a couple of needle bearings in the pan. Usually if you can identify a metal flake some damage has been done. Did you identify the OD problem as a constant increase in rpm or a severe slippage that gives you doubts that it can be driven anywhere?

The pan is a little tight for installing a drain and I always worry about those things leaking. If you want to take some effort, install an external spin on filter. This gives you almost an extra quart of fluid and extra cooling. As a bonus, removing the filter and doing a little pump out lowers the pan level enough so it can be removed without spilling a lot of fluid.

 

[wreining3]

No Overdrive

Mine wouldn't even go into 4th. It would drive all day long in 3rd. The last time I drove it, it was in 3rd and it was a severe slippage that made me think I wouldn't make it home.

I do think I will add a remote filter. Sounds like it has helped shifting problems for quite a few people.

Thanks
Wayne

 

[FIRE and ICE]

I replaced my vacuum modulator valve 2 weeks ago- had to go in from inside cab. Had to remove both seats, console, pull back carpet and remove shifter access panel on floorboard.

If you had tranny fluid come out of vacuum hose - look under the hood at the vacuum octopus (tree) and remove each hose one at a time. I found tranny fluid in my vacuum line to the 4 wheel drive vacuum device(can?)
check each line to make sure no tranny fluid was drawn into it. I was very happy to find that my brake booster line was fluid free

 

[StickmanC]

Vacuum Modulator

Fire and Ice and myself must be on the same schedule. I changed mine on 3/4/03. I did get it changed from underneath the truck by going by the Haynes Manual. They neglect to tell you though that your left arm will look like you have been in a cat fight. The only thing I removed was the heat shield. I had to use a short 10mm wrench ( Snap-on was too long and hit the bottom of the floor ) to take off the nut holding the heat shield on and then remove the stud holding the modulator bracket. You cannot see what you are doing it is completely by feel If you are not skinny ( I am, hence Stickman ) don't even try it It took me about an hour, I could probably do it in about 30 min. now that I know what to do. A very pleasant side effect is now I have NO PINGING

 

[wreining3]

Modulator removal

I'm pretty sure that I won't have any problems removing the modulator as I had already removed the transmission prior to my inquiry . I do appreciate your post though as they are sure to help some other unfortunate souls that are faced with the same problem.

Thanks Again,

Wayne

 

[StickmanC]

Dah!!!!!

Sorry, I hate working evenings.

 

[FIRE and ICE]

StickmanC
Don't forget to check your other vacuum lines. I found tranny fluid in the one going to the 4WD shifter cannister!

I read all the posts on changing the VMV but I didn't see anything about the flood of tranny fluid that came out when I removed the valve

Well I guess I'll have to chalk that one up to experience
You know its funny that the CEL light never came on or some other error code display because we were burning tranny fluid from the VMV