I have a 1998 F150 4x4 4.6L w/ automatic transmission (stock drivetrain). The truck just turned 100k miles, when I started noticing a slight pulse (or slip or vibration) from what I thought was the transmission. Initially, the pulse/slip/vibration occurred when starting from a stop on a hill while turning. The engine/transmission had to be hot, too. After you reached 10-15mph, everything was fine until the next stop.

Today, I pulled up to a stop on flat ground steering straight ahead. When I pressed the gas, the motor rev'ed up, but the truck did not move. I let off the gas and tried again. This time the truck moved forward. This was the first real confirmation that my problem was transmission related. The truck was relatively cool at that time.

As I drove home from work, the pulse/slip/vibration becomes worse as everything warms up. This has occurred for a couple months, but it's noticeably worse now.

1.) Does everyone agree that my transmission is shot.
2.) Any ballpark ideas about my expected cost to fix?
3.) Should I go with a Ford OEM from a dealer, go with a rebuild from a local shop, or some other option. I plan to keep the truck for several years pulling my boat.
4.) Should I upgrade to a heavy-duty transmission for a 1998 F150 4x4, if they are available (for towing the boat)?

Thank you in advance.

 

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Welcome to FTE cstrack. Have you checked the fluid level in the transmission? What color is it? Does it smell burnt?

 

Yes, I check the fluid level often. However, I had the fluid/filter changed 10/2005, and the fluid level has been high (changed at 93K miles, now have 103K miles). I thought it was the slope in my garage floor, but I recently checked the fluid with the truck pointing "uphill" and "downhill". The fluid level was high both times (well beyond the cross-hatched region).
The fluid color is clear w/ a minor pink tint. I would not classify the smell as "burnt", but it has a distinct odor to it.

 

I checked for info about high fluid levels, and I came across this site:
http://www.arrowtrans.com/techtips.html

From the website--I would NOT classify the fluid consistency as a strawberry milkshake, and it is more red than pink colored.

Thanks for any advice.

 

A previous posting has my truck's mileage & specifications.

The truck needed some basic service, so I took it to the Ford dealer (they usually have fairly accurate assessments of the problems). The computer contained no error codes.
They think the pulse/slip/vibration is from the rear end. They want ~$800 for new clutches, and possibly another ~$300 if a ring or pinion gear is damaged.
If the gears were damaged, wouldn't I notice a problem at all speeds? Is this estimate high for

I believe their diagnosis is correct. However, I explained the engine rev'ing from a dead stop (flat ground, wheels not turned), and they agreed this "might" be a transmission problem. This could run anywhere from $3000-4000, not counting the rear end repair cost!! They could not reproduce any "transmission" problems today during their test drive, so they are unsure whether this repair will be needed soon down the road.

Any advice for repairing the rear end or transmission?

Thanks in advance.

 

I have a 1999 f150 4x4 and it has 125,000 and it kinda did the same thing I put the truck in low gear and drove it up to 35 mph and shifted into drive and left the od off and the trans has been fine ever since and that was about 7,000 miles ago, sometimes the valve body get little bits of debris in the fluid passages,also like the other guy said check the fluid level running and in park and while it has warmed up,becomes sometimes ford are notorious for not going into gear when they are cold!!!

 

Thanks Bones. I might try the low gear procedure after the rear end is fixed.

As far as the transmission fluid level, I only check it after driving 15+ minutes.
The engine rev'ing problem occurred after the engine was warm (not hot). I pulled up to stop and look at a car for sale along the road, and I never put the truck in park while stopped. I simply left my foot on the brake, while the truck remained in Drive. After I removed my foot from the brake and pushed the accelerator, the engine rev'ed with no forward motion. After letting off the gas and pressing it again, the truck moved forward as normal.

 

Sounds like the trans to me. You could get a little vibration out of the clutch in the rear end as you are going around a corner but no way would it not move in a straight ahead motion. First of all, do you have a limited slip differential? Only limited slip diffs have clutches in them and they only keep the 2 wheels from spinning independently in a light traction situation. If the vibration is in the rear end, then all you will likely need is an oil change and then you need to add a friction modifier to a limited slip. This additive does need to be changed at the reccomended intervals according to the manual. Sounds like the dealer is trying to take you to the cleaners. Get a second opinion from a reputable repair shop.

 

JDV. Thanks for the reply. I wish that I received your post about 2 weeks ago, since I went forward with the rear end rebuild. Yes, I have a limited slip differential. The rebuild stopped most of my problems, although I still hear a slight vibration every once in a while. The vibration stopped, when I start on a hill with the front wheels turned.

I reproduced the engine rev'ing problem one other time, since the rear end rebuild. This time, I started rolling from a stop (going straight ahead), reached about 15mph going downhill, then I backed off the accelerator w/o hitting the brakes. The transmission was near a shift point. When I pressed the accelerator again, the engine rev'ed (with no apparent connection to the transmission). I backed off the accelerator and tried again, and the transmision was active.

Do you have 4wd experience? I put my truck in 4wd last week, when I was driving on snow covered roads. The transfer case or front end are making a loud growling noise, which stops when I let off the accelerator or return the truck to 2wd. I suspect my front wheel bearings, CV joints, etc. are going bad (104K miles), since they have never been replaced. Would the transfer case or transmission make a loud humming noise?

 

okay, know what your talkin about from the vibration from the rear.... They tried to sell me a new rear end... Change the oil, and there is an additive which wil fix the "chripping" or skippping whil turning... The trans is probably shot... I changed one with a "ford oem" and it only lasted 8,000 miles before ford rebuilt it under warranty... When they rebuilt it i had no problems (the problem was a bad planetary gear) I also changed the trans in a friends truck and i got the trans with shift kit installed and an upgraded torque converter from a good aftermarket shop and the cost on that one was 1505.20 but, we installed it ourself.. If you ask me, going with an aftermarket one is probably better.

 

when i replace mine im getting a performance trans so i can install a supercharger later on and not have problems lol

but good to see problem fixed