1988 Ford f-150 Auto Transmission

1988 Ford F-150 - 302 V8 Engine - AC, PS, PB - Auto Transmission

From the day I purchased the truck to a couple weeks ago, when starting, the engine would have a slightly high rpm, then the rpms would drop to normal after a short running period. The vehicle gets very little use, just short runs around town.

I've performed various work on the vehicle such as replace the PS pump, AC work, Oil Change, install Brake Pads, but have never attempted to work on the automatic transmission as that's a little out of my leaque. However I would like to know what I'm up against to avoid being taken to the cleaners as the saying goes.

Two weeks ago after making one of the short runs around town for some reason or another, and returning home, I noticed that after parking the vehicle and putting it in park, the engine was racing somewhat. Frankly I didn't think too much of it as I was coming down with the flu or something and couldn't think straight.

One week ago, needing to make another short run to the pharmacy for a medical refill, I noticed that the engine raced excessively when starting cold with the rpms dropping slightly after the notmal warm up, but they never dropped to what one would call the normal idling range..... but when putting the transmission into any position other than neutral or park, the idle appeared to drop to normal. Moving the shift indicator to neutral or park resulted in an excessive rpm range. However, at this time, the shifting of the vehicle appeared to be normal.

Today (12/29/04), starting the vehicle immediately resulted in a very high idle rpm, so much that by reflex I hit and released the gas pedal quickly in an attempt to free it should it have stuck on something. This reflex action had no effect and the high rpm continued, dropping only slightly after a short warm up period.

My location is central west Florida so keep in mind that I am not experiencing any kind of cold weather interference.

Pulling away from the house, applying a small amount of throttle, the engine appeared to roar but there was very little accelleration, such as one would experience with a slipping automatic transmission. I gently accelerated the vehicle up beyond what one would consider the first gear range, and carefully guided it up through the second gear range. After that, the third and fourth gear range seemed to operate as they should. The second gear range may have been fine also but I didn't want to force the issue as the saying goes.

However, even though I apparently was experiencing slippage, before pulling away from the house, the high rpms dropped to normal as soon as I shifted from "P"ark to "D"rive.

Thinking the transmission might be low on fluid, I purchased a quart of tranmission fluid while out..... the correct type for the 1988 Ford F-150.

Arriving home, I looked under the vehicle and found that the bottom of the transmission and the bell housing was thoroughly wet with oil, fluid, whatever. I didn't feel like crawling under there just yet (Damn Flu!).

Engine not running. I checked the transmission dip stick and found that the fluid was extremely high and it was not RED in color. The color appeared to be more yellow than anything else.

Engine running, transmission in "P"ark. I checked the transmission fluid level and found it still to be extremely high, yellowish in color rather than red and it appeared to have bubbles in it... or it was foaming. The feel of the fluid felt to me like it was of a higher viscosity than normal.

I have never added anything to the transmission fluid that would tranform the color from RED to this yellowish look and have no idea how that would take place.

Hopefully I have not forgot to enter anything and will await a reply.

Joe

Reply to
ReevesJ32
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I've never pulled an engine before so this may way off base, but let me throw some of this on the wall and see if any of it sticks.

If...... a rear main seal going bad Could cause a vacuum leak, that would explain your high idle and if a rear main seal was going bad it Could leak oil and or antifreeze out near the bell housing, I believe. But those are both just shots in the dark.

Now here's the part I''m Really not sure about,,,, If a rear main seal has went bad and is leaking oil and or antifreeze, could it somehow get into the transmission fluid? Is there a direct path/connection there somewhere that would allow your transmission fluid to get contaminated.

Just curious to find out how far fetched those theories are....

W.D {{{ Backyard Wanna-Be Race Wrencher, when I grow up }}}

Reply to
Wheeler.Dealer

Rear main seal won't leak anti-freeze. It seals oil in the crankcase, and there is no vacuum in the crankcase, but there is pressure.

Don't know how the fluid in your Transmission turned yellow, but it didn't come from the rear main seal.

Maybe a leak at or in the radiator, mixing anti-freeze with the fluid in the transmission cooler side of it, and getting in that way through the cooler lines.

Spdloader

Reply to
Spdloader

Hey Spd...

I gotta 1992 302 and theres antifreeze coming out of the bell housing, I figured mine to be the rear main but,,,,,,, if it doesn't hold in antifreeze what else could it be ??

w.d

Reply to
Wheeler.Dealer

Frost plug

message

Transmission

Reply to
Hairy

Hard to say without seeing it, but it could be coming from anywhere. Cracked block, cracked head(s) leaking head or intake manifold gaskets, or anywhere on the back of your motor and running down and into the bell housing, then out the bottom. The rear main seal protects the area around the rear main bearing of the crankshaft from leaking oil. There is no anti-freeze in a crankcase, unless you have major, and I mean major, problems.

I can only guess that it's a gasket failure, but not the rear main seal.

Spdloader

Reply to
Spdloader

There are two soft plugs back there. Some people call them freeze plugs.

s

Reply to
Steve Barker

The high idle is typically caused by intake manifold leaks between the upper and lower manifolds. It's darn near a universal problem. I recommend NOT getting that problem entangled with the transmission's behavior in your mind. If it's dropping to normal speed when you put in gear, then your tranny is going into gear and putting a small load on it (which is okay). There's a chance it could be another problem, such as the IAC motor having a problem, or a vacuum leak elsewhere. Get the vacuum leak fixed first.

Reply to
Joe

Hi Joe.... I have exact the same engine as you and same model 1988, but an E150van. I have been trou most of your problems with my car. First thing I would do is to order a new gasket to have between upper and lower intake manifoil. And an AIC, because it is good to change this at this time. Disconnect the battery and change the gasket and IAC. Put on the battery again, and I am pretty shure your idling problem is gone by the wind. This is a very known problem on these engines when they pas about 100k miles or so. It causes wakum leak, and the idle revs up. (can be tested with the engine running at idle, and spray some startgas in to the top of the engine around the upper intake from outside. If it revs up this is your problem. Aboat the tranny, I would (since the fluidlevel is OK, and it don't misses any trans fluid) buy a new filter and gasket, and about 14 litres of Dexron III. Change the fluid and filter and gasket, and kross fingers for it is OK. This is what I would do with your car from my point of wiew, and I have seen and hawe both problems on my car. When I did these things everything is OK. Regardes, Tor Elling in Norway.

Reply to
Tor Elling Rustad

nope

vacuum at idle and low load, slight pressure under heavy load if blow-by is excessive

Reply to
TranSurgeon

In the crankcase?

Spdloader

Reply to
Spdloader

yup

PCV valve provides suction thru the crankcase to the opposite valve cover

Transmission

Reply to
TranSurgeon

I guess I'm thinkin' about the performance engines I've been around with no PCV system, crankcase pressure is a real issue with high horsepower motors, where there is excessive blow-by.

Spdloader

Reply to
Spdloader

Wheeler.Dealer..... Pertaining to my 1988 F-150.

Your reply to another party (not my original post) about the oil cooler got my attention as the transmission fluid is now the color of my anti freeze solution, and my coolant level has dropped considerably.

Looks like I'm faced with a transmission drain and refill project, coupled with the filter replacement of course... and replacing the oil cooler within the radiator.

Anyone agree or disagree with that? And if so, what are your thoughts.

Joe

Reply to
ReevesJ32

While I'm not going to go into the trans problem, here is my advice on the idle problem. (The ASE study guide on transmissions says "diagnose and fix any engine problems before assuming something is wrong with the transmission") Assuming this is a FI vehicle; I wouldn't change the IAC yet, but get some throttle body cleaner and scrub the butterfly out real good. If possible, remove the IAC and spray it out also. Another culprit in Fords can be the coolant temperature sensor. I have a scanner to tell me what it's reading. Sometimes when they fail they lie to the computer and tell it that it's 15 degrees out when it's 60.

Reply to
Steve

I'm going to pull the radiator, remove and replace the transmission oil cooler, drain the transmission and replace the filter, then after replacing the associated fluids, hope that the problem is corrected.

Between the high idle (In Park & Neutral) and the yellow fluid (anti freeze most likely) being in the automatic transmission, the transmission is by far the first thing I want to correct. However, since these two problems occurred at the same time, I can't help but feel that the two are connected.

Joe

Reply to
ReevesJ32

message

Transmission

Reply to
Lori

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