6 speed transmission problems
 

I wanted to let people know about a problem that I have been having. I searched through the forum and couldn't find anything like what I have been experiencing. There is a bit of a story here so bear with me...

I bought my truck with the manual transmission for one reason. They are strong. Until this experience I have had no unusual issues with my truck whatever.

About a year ago, while hauling my camper and small boat back from an extended weekend trip I had to pull off the road and help out a buddy that was having issues with his rig. When I took off to head home the transmission wouldn't shift properly into first and second gears. I was able to drive the truck home being careful to avoid as many stops a possible.

I took the truck to a local transmission shop that came with a recomendation. The owner drove my truck and said that the clutch felt good and all of the other gears (reverse, low, third, fourth, fifth and O/D) were all in good order and working properly. When shifting into or out of first and second it feels like there is peanut butter in the transmission. No clunking or grinding sound is present like a syncro going out. And it's nearly impossible to feel the difference between gears and neutral, just lots of resistance throught the entire shift/trhow.

The bottom line is that the mechanic said he had never seen anything like this with these transmissions. His best guesses were a bent rail, bent shifting fork or possibly a syncro issue that wasn't completly "out" yet. But basically he wouldn't know what was wrong until he gets into things. I've been limping the truck around for almost a year now since the quote was $600 - $1,200 and that was just a guess. I'm thinking for that kind of money I could do most of the upgrades to my truck that I would like to do (exhaust, guages, tuner, etc.)

But I have decided that I can't wait any longer. I've got a week long camping trip coming up and want things to be tip top for that drive and leave some time for break in (no pun intended).

Yesterday, I dropped the truck off at the transmisison shop to get the problem fixed.

I'm upgrading to full synthetic transmission fluid when the work is complete. And I'm going to have the mechanic take a look at the clutch and throwout bearing while he's in there. I also asked to have them save the defective parts so that I can see what happened.

I'll post uptades as things progress.

TinyWonder

I say YES to everything you said. We also need pics. :-wink

Hey Tiny,
I'v been wanting to go Syntheitc in my 6 speed, What are you going to use?

https://www.ford-trucks.com/forums/p...161954&thumb=1
The Truck

I'm partial to AMSOIL. I've got a buddy that gives me a good price (he's a dealer). From what I've seen their engine oil is superior to most other synthetics and has the ability to extend the drain intervals. But I'm open to suggestions.

The transmission shop didn't think to highly of AMSOIL and suggested that I use theirs... Valvoline Synthetic.

TinyWonder

subscribing, would like to see what they come up with.

Interesting, subscribing to this thread as well.

Subscribing.

Tomorrow morning myself and a couple of guys are dropping my 6 speed to replace the throwout bearing and fork. When I bought the truck the PO had just put in a whole new clutch. Now 10k later the throwout is squealing away. I believe the PO didn't know of the weak fork in the 99's. We'll see what we find tomorrow. I am also interested in how yours comes out.
By the way, everyone told me that to drop the tranny myself was just too big a job for the garage mechanic. The truck is in the garage on the stands and the only thing to do is loosen the trans bolts, pull er back and see what we find. The prep work I did by myself and it wasn't the horror everyone said. I'll post pics and commentary on the work.

Please tell me you checked the fluid level in your hydraulic reservoir prior to taking the truck to the shop. My truck became very difficult to shift into first. Like you said, no grinding or anything, just hard to move the lever into place. Shifted just fine with the engine off and no difference in feel on the clutch.

I had a slave cylinder in the clutch hydraulics that developed a leak and my reservoir was empty. $50 to autozoo for a new slave and a little brake fluid and I was back up and running.

Tiny,
Been going some lookin around and this is some of what I found.

The guys on these two sites (Powerstroke Nation & Bob is the Oil Guy Forums) are using These Oils in there ZF6s.

1-Mobil 1 ATF Synthetic, 2-Red Line MTL, 3-Amsoil ATF, 4-Royal Purple Synhcromax, 5-Royal Purple Max ATF.

Any input from some of the other Guys or Gals running ZF6s would be Great (Good or Bad)

https://www.ford-trucks.com/forums/p...161954&thumb=1
The Truck

I changed mine to Mobil 1 @ 54,000 & again @ 98,500 & I am happy to report no problems. When I took the fluid out @ 98,500 after 44,000 miles it looked real nice. It was red, had no burnt odor. It looked good enough to have left it in. Hope this helps.

Subscribing here too.
I had a bearing fail in my ZF6.
No question because when I changed the fluid it came out looking like mother-of-pearl, full of fine metal flakes.

I made the presumption that this question was directed at me. Fortunately for me and your concerns I know that this is not in fact the problem. My slave cylinder went out about a year and a half ago. The clutch pedal went down to the floor and stuck there. It was a little scary when it happened. I replaced the slave cylinder and bled the hydraulic lines (I wish I had my mighty vac when I did this job) which was a royal pain.

The transmission is hard to shift in or out of first and second gears weather the engine is running or not.

I am religious about checking under the hood and checking all of the fluid levels. In fact I just checked three weeks ago before leaving and returning from a camping trip. The next day my truck got sabotaged by a squirrel and it's been sitting in the driveway until yesterday (see my other thread).

I had considered taking the transmission out myself. The shop wanted $400 for R & R. After talking with the shop owner I decided to let the pro's do this one. One bit of advice on doing the work yourself... be very careful to get the transmission ligned up correctly when bolting everything back together. Apparently there are some studs that fit into the transmission and if things aren't just right when you tighten things down they break off causing all kinds of trouble. And I remember the shop saying something about supporting the rear portion of the engine while the tranny is out too.

TinyWonder

I've run Mobil 1 synthetic ATF in mine and frankly could not tell the difference between it and regular ATF. They feel the same and both come out clean at 50k miles.

TinyWonder I bought the replacement tranny from Fleet Pride.
They are an authorized ZF6 distritributor and the cost at that time was around $2400.00 for a complete unit delivered to my shop.