First, I'd like to thank you in advance for your help. I've read several threads and am quite impressed with the level of expertise shared here.

This post will be lengthy, however, I feel the more information one gives, the better the advice given.

I just purchased my first Ford, a 1993 Explorer 2WD A/T 4.0L V6 with 167,000 miles.

The vehicle did not move when I bought it (yes, I knew this when I bought it, I got it cheap). I say it did not move because it did start easily, even after sitting in a parking garage for 18 months. When I first started it I noticed a deep knocking noise, about 1 knock per second, coming from the bell housing area. When the engine was revved up to higher rpm's the knocking did not increase in intensity proportionally to the increased engine rev's. It did knock faster, just not corresponding to the engine. When placed in gear (reverse) there was no noticeable engagement of the transmission, however, when the engine was again revved up to higher rpm's the vehicle began to move slowly, very slowly. I backed it out of the space and placed it in drive, again, no noticeable engagement of the transmission and, again, when revved it began to move very slowly. I ended up moving it over 2 parking spaces and towing it home a couple of days later. The guy I bought it from said that he was driving it to work one morning when it felt like the rear end let go (it didn't, I checked) and the knocking immediately started, he then had very little or no power although the engine was running fine. He limped it the last few miles to work and coaxed it (probably not gingerly) up the ramp into the parking garage and never moved it again until I came along.

I guessed the problem was either the converter or the transmission pump. I removed the transmission and took the converter to a local shop and had it rebuilt. I drained all the fluid from the transmission (dirty, maybe burnt, fluid but no metal shavings), replaced the filter, flushed out the cooling lines with shop air, installed the rebuilt converter and put the transmission back in the vehicle.

I put 5 quarts of fluid (Dexron III) in the transmission, put the rear axle on jack stands and started the vehicle. The same noise was immediately apparent. I put the transmission in reverse and revved the rpm's, after a few moments the wheels started to move in reverse, I stopped the wheels, put it in park and checked/added fluid. I put it back in reverse and nothing, I put it in drive, nothing. I checked the fluid level again and it was just below the hatched level, i.e., there seemed to be plenty, I had added a total of 6 quarts.

The same knocking noise is ever present regardless of the transmission gear selector position. It sounds like the transmission case is being firmly tapped with a ball peen hammer persistently. When the transmission was off the vehicle I checked the condition of the flex plate and it was fine, no cracks or broken welds.

I still think it's the pump (since it wasn't the converter), however, I would like to hear it from someone else with a little more experience than myself.

Also, I have read that, for this particular transmission, the pump MUST be correctly aligned (with a $100 tool) or the whole job will be toast. Is there any way to do this with confidence without the tool? I've read in another thread here that it can be aligned with the converter but there were no specific instructions.

If it is the pump, should I also go ahead and rebuild the transmission? Would it be that difficult? Are there any more special tools needed? If I do rebuild it, what parts should I replace? Although I don't know for sure, it seemed as if someone had already been in that transmission before.

I have the luxury of having some time to work with this, I don't need the car immediately. I've been quoted anywhere from $500 to $1800 for a rebuild job (not including the pump) from local transmission shops. I'd like to save some money but also be confident the job is done correctly.

Thanks again for your time.

 

Well, I've ordered the ASTG transmisison manual, I guess I'll see what insight I can get from there.

 

unless you find obvious damage to the bushings. In that case you wont need the alignment tool if you don't remove the pump bolts. I'm all for cheap "rebuilds". No reason to put money into a 93. The real problems will be obvious when you take it apart. It's not rocket science, just take your time and mark everyting as it comes out. I've written some procedures for different sections of the transmission using easy to fab tools.