zf 5spd problems

[pitsingerk]

7.3L w/ 5spd / 4x4. I'm having issues with the transmission. When in any gear, 1-5 or reverse, the truck will take off fine, but then start to sound like it's grinding and the truck w/ no long move under it's own power. I've had the trans apart about a year ago, replaced a couple bearings and the sychros along with the springs and retainers (I think that's what they are called). I put maybe 6-7k miles on since then. I let my brother use it while his was being repaired and it got returned like this. Could this maybe be a clutch issue (not sure how many miles are on it) or do you think it would be internal. This is happening in all gears, though sparadic in forward gears, always in reverse. I say sparadic because I could take off, 1st, 2nd, 3rd, then it does it. Or I take off and it does it in 1st. Transmission is coming out this weekend, just trying to get an idea what to look for. Any help will be apprecitated.

[Buffalo444]

Originally Posted by pitsingerk

7.3L w/ 5spd / 4x4. I'm having issues with the transmission. When in any gear, 1-5 or reverse, the truck will take off fine, but then start to sound like it's grinding and the truck w/ no long move under it's own power. I've had the trans apart about a year ago, replaced a couple bearings and the sychros along with the springs and retainers (I think that's what they are called). I put maybe 6-7k miles on since then. I let my brother use it while his was being repaired and it got returned like this. Could this maybe be a clutch issue (not sure how many miles are on it) or do you think it would be internal. This is happening in all gears, though sparadic in forward gears, always in reverse. I say sparadic because I could take off, 1st, 2nd, 3rd, then it does it. Or I take off and it does it in 1st. Transmission is coming out this weekend, just trying to get an idea what to look for. Any help will be apprecitated.

hmmm.... try starting off, getting up to like 30 mph then shift directly to overdrive and lug it down to about 600 rpm, then hammer it and see if it seems like the tach speed and actual speed don't correlate properly. Do this multiple times. Also, is there any play in the shift lever? Like does it slop around at all?

[pitsingerk]

My son has already pulled the driveshafts and is pulling the transfercase as I type this. I tried going from 2nd to overdrive to get it home, no difference. I had at first thought it was the shifter because it was sloppy, I put in a shifter from a parts transmission I have and it made no difference. Forgot to mention that in first post. When I changed out the shifter, I also pulled the detent springs to make sure they were ok and they were.

[Buffalo444]

Originally Posted by pitsingerk

My son has already pulled the driveshafts and is pulling the transfercase as I type this. I tried going from 2nd to overdrive to get it home, no difference. I had at first thought it was the shifter because it was sloppy, I put in a shifter from a parts transmission I have and it made no difference. Forgot to mention that in first post. When I changed out the shifter, I also pulled the detent springs to make sure they were ok and they were.

hmmm... I would ask your brother his driving habits in your truck. See if he rode the clutch or forced it in gear. You could have roasted some sychro's, burned the clutch up, or maybe affected the flywheel surface. But thats just a couple WAG's from what I can glean.

[madpogue]

How have you determined that it is the tranny and not the transfer case?

When the engine no longer propels the truck, have you tried it, just for grins, in 4HI or 4LO?

[pitsingerk]

Damn, didn't think of that, transfercase is already out on the floor. I'm pulling the drain plug on the transmission when I get home tonight to look for grindings, will do the same on the transfer case.

[madpogue]

Before draining the t-case, turn the input shaft and see if the output turns. That'll at least tell you something about its workings.

Hmm, I just had another thought - grinding, then no propulsion .... are you on the original dual-mass flywheel? Worth looking at, if you're pulling the tranny.

[blue94]

I'm sure you already figured this out, but I just had a similar problem and it turned out to be the shift forks and bushings in the transfer case(extremely worn) due to a leak in the transfer case rear oil seal.