Ranger Transmission Leak

[kwijibo]

Have a 93 Ranger with 3.0L, 150K miles, RWD with an automatic transmission. I am experiencing a slow undetectable transmission leak that will effect changing gears every couple weeks or longer. When this happens I can back out of my driveway, but when I change to overdrive it is slow and takes a short bit then jerks into gear. I keep an eye on the transmission fluid and top it off when it needs to be refilled. I recently read online about a vacuum modulator on the transmission that can cause these symptoms (erratic shifting, hesitating going into gear and losing transmission fluid without a trace of a leak) if its faulty. Has anyone experienced this before or think this may be what is happening or think there is something else wrong?

 

[440Magnum]

Vacuum modulators used to be the classic fix for Ford and GM transmissions that mysteriously lost fluid and started shifting strangely (Chrysler never used a vacuum modulator). Another indicator was the vacuum line leading to the modulator "sweating" with transmission fluid since vacuum lines were permeable to it. But I honestly don't know when Ford and GM quit using them. 1993 seems like it might be a good possibility.

 

[kwijibo]

This is what I found on another website. This particular transmission was used on the ranger from 85-94. That's why I was interested to see if the vacuum modulator is the fault here.

A4LD
This transmission is a rear wheel drive 4 speed automatic. Common symptoms are erratic shifting, hesitating going into gear and losing transmission fluid without a trace of a leak. You have a modulator on the passenger's side of the vehicle pointing towards the driver's door. Pull the rubber line off the modulator and see it trans fluid comes out of the line. Now, if it does your modulator is no good. It can cause any of the above symptoms.

 

[bdcardinal]

Looks like a 93 still could have a vacuum modulator. They list 6 different ones depending on the trans tag number.

 

[EricF]

I'm showing a TM54 from Standard Ignition..

 

[440Magnum]

Explains all the symptoms, fairly simple job... sounds like something worth trying.

 

[jimvegas]

That's most likely the problem. Pull the vacuum line off of the modulator and see if fluid drains out or if it's wet inside the line. Used to sell tons of these back in the day...

 

[kwijibo]

I would like to say thanks to those who responded to my question. I did crawl under the truck and of course the exhaust runs right in front of the modulator so it's a very tight fit. So I called a local transmission shop and explained the situation and they also said it's probably the modulator. So they did a look and noticed fluid coming out of the vacuum line when it was pulled. They replaced the part, topped off the transmission fluid, took it for a test ride charged me $50 and so far no leaks and it's shifting fine. Again thanks for the help.