Hi. New to the forum.

I bought a two-wheel drive 1988 F150; 302 auto (w/OD) transmission with 134,000 miles. Mechanically it’s sound except for a small leak which I think is transmission fluid (red in color). I’ve only noticed the leak twice (out of 10 different trips), which leaves a puddle about the size of a baseball. I can also see red fluid on the transmission bell housing. I think it leaks only when the motor is running because I haven’t noticed it dripping when the motor is off, and I can smell a slightly sweet scent from inside the cab when driving it. The transmission doesn’t appear affected by the leak as it shifts very smoothly through all the gears, doesn’t clunk, whine, or slip, and the OD engages and disengages as it should.
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I only paid $500 for it, so I’m reluctant to spend a lot of money fixing it. My plan is to use it as a dump-runner, general hauling vehicle. I’ll probably drive it every couple of weeks and don’t see myself putting more than a 100 miles a month on it. I figure I’ll need to keep the transmission fluid topped off whenever I drive it.

My questions are:

1. Does the absence of oil indicate this is a transmission seal leak?

2. Anything I should be concerned about in terms of driving it with a full payload and putting stress on the transmission?

3. Should I flush the transmission first, then keep topping off with the same brand of transmission fluid? I’ve always heard not to mix and match transmission fluid, but wanted to know if this was still true today.

Any feedback would be appreciated.

 

1. The red color fluid tells you right away its tranny fluid.

You can either a.) ignore it, but monitor your fluid level CLOSELY and add in a quart as needed or b.) tear it all apart and trouble shot which seal is leaking.

2. You should be concerned if you drive it with a full payload without checking the fluid level. High amounts of stress will most likely only increase the leak. Should you drive with low fluid, expect high temperatures, sliage, and alot more damage.

3. Flushing then refilling is by far the best, safest option should you decide to "keep topping off." But the leak isn't going away and you have to remember that.


Another option that some support, some don't is to add transmission additive like Lucas. I can't recommend you one way or another as it appears each person's experience with additives is different. I've seen it help some vehicles, and other cause 10 times the number of problems it solves. Be extremely careful what you add if you decide to add anything and be prepared it may cause more harm.

 

The "sweet" smell in the cab is mare than likely your heater core dripping coolant in the box..old transmissions don't generally smell "sweet" they smell more..burnt.

That small of a leak, you can try something like Lucas Tranny additive, see if it will help swell up your seals a little, but I really don't have any faith in those things, and if it does anything, it will be temporary at best...but if you don't use it much, give it a try.. 8 bucks is better than a few hundred for a dump runner.

I suppose if it was mine, I'd just do a normal tranny service, and make sure the pan is sealed good, and see what happens.