1993 Ford Explorer: Transmission fluid in vacuum manifold.

1993 Ford Explorer: Transmission fluid in vacuum manifold. | Mechanical /Maintenance Forum | Bob Is The Oil Guy:

1993 Ford Explorer: Transmission fluid in vacuum manifold.  srivett  Registered: 12/21/04 Posts: 894 Loc: Sudbury, Ontario My brothers 93 Explorer has had an appetite for ATF over the last year and we'd like to get down to the bottom of it. His truck has a V6 and an auto with overdrive. Anyway, we started noticing problems when the rubber vacuum lines on the vacuum manifold started blowing off on start-up. The ATF was softening the lines and caps enough that they wouldn't hold on! The line from the manifold to the cruise control also had ATF in it so we removed the line and capped the manifold for safety reasons. The engine also has a slight rattle during hard acceleration. Power is still there, we towed my VW Golf 500 km on a dolly without problem. Uhaul would not rent a dolly to us because it was an Explorer but that is another topic. Why is it sucking up ATF? Is there a PCV style vent on the tranny? Is part of the tranny vacuum operated? The truck doesn't get used a lot due to it being a pig on gas but it does burn off 2 litres of ATF a month. Thanks, Steve Top

#559888 - 01/24/05 09:17 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. Chris142  Registered: 06/05/03 Posts: 10696 Loc: apple valley, ca Is the truck a 4x4? Top

#559889 - 01/24/05 09:19 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. tmorris1  Registered: 07/15/03 Posts: 2028 Loc: MN I saw a TSB on this once. I can't remember exactly what it is, but there is a modulator valve (or something similar to that) that can go out and suck tranny fluid into the intake. I think it is a common problem. [ January 25, 2005, 01:27 AM: Message edited by: tmorris1 ] Top

#559890 - 01/24/05 09:26 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. tmorris1  Registered: 07/15/03 Posts: 2028 Loc: MN Top

#559891 - 01/24/05 09:52 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. srivett  Registered: 12/21/04 Posts: 894 Loc: Sudbury, Ontario Chris: Yes it is a 4x4. He has another problem where the 4x4 on demand button doesn't always work. Sometimes the lights in it are dim and it doesn't want to shift. Steve Top

#559892 - 01/24/05 01:46 PM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. mechtech  Registered: 08/11/04 Posts: 2387 Loc: Chicago area Yes, it's called a vacuum modulator. About $20.00 and easy to replace. The unit will be on the trans/transfer case. Clean out the line while you're at it. Top

#559893 - 01/24/05 03:37 PM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. ZR2RANDO  Registered: 06/10/02 Posts: 885 Loc: North Carolina Blazers (at least the 95 yr model anyway) do it too. The 4x4 switch down at the tranny is vacuum activated, the switch (the modulator mentioned above) leaks and then vacuum does the rest. Guess Ford and Chevy both hired the same guy huh? Top

#559894 - 01/24/05 06:33 PM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. TheLoneRanger  Registered: 05/27/02 Posts: 1454 Loc: Southeast United States Steve, it's definitely a bad modulator valve as was stated. It's held onto the transmission (passenger side) with a bracket with one bolt, remove the bolt and pull it out. Be VERY careful and don't lose the small actuator rod. The trouble in the 4x4 is probably from a faulty shift motor. I've heard you can remove them and clean the contacts, etc, to get them working smoothly again. It's worth a try before applying for a loan to replace it. Top

#559895 - 01/24/05 11:38 PM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. C4Dave  Registered: 04/25/04 Posts: 399 Loc: Tennessee My 92 Explorer did the exact same thing. It was the vacuum modulator valve. It's not easy to get at. Its on top of the transmission. You can't really see it. I let a transmission shop do mine. I think I paid about $60. It solved both the ATF and pinging problem. It apparently is a common problem. Top

#559896 - 01/26/05 07:05 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. Chris142  Registered: 06/05/03 Posts: 10696 Loc: apple valley, ca Usually what happens is that the seal between the trans and transfercase goes bad. The trans slowly over fills the transfercase with trans fluid untill it's so full that it sucks the fluid out of the transfer case and through the entire vacuum system. Top

#559897 - 01/26/05 07:07 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. srivett  Registered: 12/21/04 Posts: 894 Loc: Sudbury, Ontario Thanks guys, I told my brother what the problem is and seeing as it is a cheap fix I'm sure he'll get it done. He hasn't been doing much work on the Explorer because they are not worth anything at resale. It definately isn't worth fixing the 4x4 properly but I will clean up the electric motor to see if that helps...we heard about this problem before but decided not to pay up. What does the vacuum modulator do? Will fixing it help the mileage? Cheers, Steve Top

#559898 - 01/26/05 10:58 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. C4Dave  Registered: 04/25/04 Posts: 399 Loc: Tennessee The vacuum modulator valve tells the transmission when to shift by sensing engine vacuum. There is a rubber diaphram in the valve that ruptures over time. The engine vacuum then sucks transmission fluid into the engine. Replacing the valve probably won't have much effect on fuel mileage. ATF does reduce the octane of gasoline, hence the pinging. Explorers are also known to develop engine deposits which can also cause pinging. Ford recommends driving the vehicle at 3000 rpm or more for 20-30 minutes to burn off the deposits. This works for me. Others have used Seafoam or water injected into a running engine to successfully remove deposits. Do a search on this forum or the explorerforum.com for more info. Also, make sure he checks the transmission fluid level. It might be low. Top

#559899 - 07/19/05 02:04 PM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. srivett  Registered: 12/21/04 Posts: 894 Loc: Sudbury, Ontario Tomorrow is the day that I finally fix this thing. My brother was all upset that it's still puking ATF after having the pan dropped today so it has to be the modulator. He's thinking of selling the truck because the amount of oil it leaks is disgusting. I'm also going to be driving around approaching people about buying parts off of their rolled Explorers that're up on blocks alongside the highways. There are a lot of them! If I find one with a manual shifting transfer case will I be able to put it in without changing the front and rear driveshafts? I suppose that it would help to switch to manual hubs too, eh? The computer may have trouble shifting the hubs when the auto-transfer case is gone. The truck needs a right hand side front axle and a stearing box too. It's going to be a long day... Steve Top

#559900 - 07/20/05 01:20 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. mechtech  Registered: 08/11/04 Posts: 2387 Loc: Chicago area Very common is older transmissions with vacuum modulator. The diaphram leaks, and engine manifold vacuum pulls ATF fluid into the manifold. Top

#559901 - 07/20/05 07:44 AM Re: 1993 Ford Explorer: Transmission fluid in vacuum manifold. srivett  Registered: 12/21/04 Posts: 894 Loc: Sudbury, Ontario Mechtech: That's the part I changed today. I think the vacuum line was filling with fluid while the engine was running and then it would leak out past the hose on shutdown. The line had turned really soft and wasn't holding on tightly at all. I drove around on the highway in 2nd to try and bring up the temps to burn off any old ATF but it didn't work. I changed the thermostat but after seeing the temp drop with the opening of the new FORD OEM stat I couldn't get up past 1/4. I'll have to read up on fan clutches next.  It freewheels with the engine off but I dunno about trying to catch it when the engine is on.  For anybody who has to do this job all you need is a deep 10 mm 1/4" drive socket and ratchet. The truck must be completely cold as you'll be up close and personal with the catalytic converter. The heat shield is held on with a nut which is threaded onto the end of the stud. This holds the clip that holds in the modulator. It's pretty simple but you'll never be able to see what you're working on.