# 1988 f 250 using excessive ATF **URL:** \ **Category:** Factual Questions\ **Created:** [June 15, 2014, 1:20am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799 "2014-06-15T01:20:48Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [June 15, 2014, 1:20am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/1 "2014-06-15T01:20:48Z")
My first thought was a bad vacuume modulator as I don’t see much f a leak. After sitting for a few weeks a saucer size spot develops from seepage at the dip stick tube o ring. I just had the engine overhauled and they must have damaged it. But the amount of fluid I am using is much greater, like 4 qts in a 100 miles. ``` I crawled up under the truck today and don't see a modulator anywhere. No oil dripping when running that I can see. Are they somewhere different than they were in the 1970's? r/r of trans is what I remember. Did they do away with them? ``` ---
**Author:** ![excavating\_for\_a\_mind](https://avatars.discourse-cdn.com/v4/letter/e/e8c25b/32.png) [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)\ **Post date:** [June 15, 2014, 1:39am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/2 "2014-06-15T01:39:36Z")
I had a '79 3/4 ton van, the modulator was on the right side, about the middle of the pan. I don’t know if there the transmission is different between 79 and 88. I think 88 is before they started going electronic, so it might be. If it isn’t the vacuum modulator, the only other place I can think of is the transmission oil cooler in the radiator. See if it is ending up in your coolant. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [June 15, 2014, 1:42am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/3 "2014-06-15T01:42:03Z")
> [@excavating\_for\_a\_mind](#): > > I had a '79 3/4 ton van, the modulator was on the right side, about the middle of the pan. I don’t know if there the transmission is different between 79 and 88. I think 88 is before they started going electronic, so it might be. > > If it isn’t the vacuum modulator, the only other place I can think of is the transmission oil cooler in the radiator. See if it is ending up in your coolant. Coolant looked good. Right after your post I found a pic on line right where you said it was. Let you know what I find. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [June 16, 2014, 1:33am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/4 "2014-06-16T01:33:36Z")
Is it possible that it’s leaking out of the dipstick or the vent but only when you’re driving down the road? If it were really sucking in a quart every 25 miles through the modulator, you should be leaving a pretty good smokescreen behind you! ETA: Unless it’s a diesel I suppose. But then you’ve probably got the smokescreen all the time anyways. 🙂 ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [June 16, 2014, 5:14am UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/5 "2014-06-16T05:14:53Z")
> [@GreasyJack](#): > > Is it possible that it’s leaking out of the dipstick or the vent but only when you’re driving down the road? If it were really sucking in a quart every 25 miles through the modulator, you should be leaving a pretty good smokescreen behind you! > > ETA: Unless it’s a diesel I suppose. But then you’ve probably got the smokescreen all the time anyways. 🙂 I never see any smoke. I was thinking the same thing about flowing out the dip stick tube when I am going down the road. It doesn’t leak when idling but does leave a small puddle after sitting. Tomorrow if I have time I will inspect the line off of the modulator for oil residue, if I don’t see any I will change the oring on the tube and try it again. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [June 16, 2014, 2:13pm UTC](https://boards.straightdope.com/t/1988-f-250-using-excessive-atf/690799/6 "2014-06-16T14:13:55Z")
I’ve got one of these trucks! 88 XLT yada yada yada. Outside The Dope, the few places I’ve got any decent info from people in-the-know was [Fordbarn.com](http://Fordbarn.com) and [Ford-trucks.com](http://Ford-trucks.com) You might try there. I found a guy who had a old, unobtainable part I needed for my 65, and he \*gave it to me! \* Very groovy! Good luck!