I have a 1992 F-250 with a 460 and a zf-s5-42 transmission. About a week after I purchased the truck I started to get a "growling" sound when I disengaged the truck into 2nd gear (I start in 2nd, 1rst is a granny gear only), and it would "growl" again in 3rd going around corners if I took them slowly enough for the RPMs to be low.

I took it to a local transmission shop and they gave me a free diagnostic and said the pressure plate was going out, along with some linkage issues. I have noticed that the clutch pedal only engages when a few inches off the floor now and shifting while the truck is cold must be done slowly. Once warmed up the shifting is fine.

My quote for a new clutch linkage work came in just under 1k. This also includes servicing of the front / read diffs, transfer case and tranny.

Does this sound like the right diagnosis for my truck?

The last thing I want is to pay for this repair and have the noise still be present. I called my father in law who is a pretty decent wrench turner and he said the quoted price was fair but I wanted to ask in here just in case we overlooked something. You all seem to have great knowledge of the Ford trucks and transmissions and any feedback you have here is appreciated.

Thanks!

 

A growl at really low RPM is considered normal for the ZF - mine does that too if I lug the engine a little bit. There really isn't a whole lot to the clutch system, a master cylinder, slave cylinder, and a hydraulic line in the middle. I would try bleeding the system first and see if that helps with the function of the clutch pedal. Also check to make sure it's getting full stroke and that the firewall isn't flexing. Unless that cost includes a new clutch and pressure plate, it seems expensive to me.

Have a look at the ZF troubleshooting guides here: ZF Friedrichshafen AG | Literature

 

Hydraulic Clutch Troubleshooting .: Articles Have a read here as well for low pedal problem.

 

Thank you for the helpful replies.

I was checking things out a bit last night and the firewall does not flex. The clutch master cylinder still has plenty of fluid so I am not sure how air could have been introduced into the system to require bleeding it.

The clutch pedal will sometimes not return completely to the top of it's stroke however I think this is due to the odd spring setup that pushes the pedal back up from the firewall instead of pulling it back towards the steering column.

There is a little white retention clip on the plunger mechanism that attaches it to the pedal that is broken, it seems to allow the plunger to "wobble" a bit. I have read on here I can get one from the "help" section of most part stores for under $5.

The cost includes a completely new clutch kit priced at $430, I am sure this is double his cost on the parts as is standard for many shops. The servicing of the read diff, transfer case, and transmission alone would cost me $300 (front is drain and fill so it's cheap) if I were to have them done separately. They are doing the full service vs. a drain and fill on all of the gear boxes but the front.

Thanks again for the advice, I really love that a back yard mechanic with limited experience (like me) can come talk to guys that really know their stuff here. I will ask the mechanic a few questions about their ZF transmission experience and confirm this cost replaced every part of the clutch this morning.

 

Does your transmission also growl a little bit when engaging the clutch from a stop in second gear?

I may try a new plastic bushing and bleeding the clutch before committing the money to the truck. I know the gear boxes require service and shifting when cold is a little tight.

 

I ended up turning the truck in for repairs today. I asked to re-explain everything I was getting and here it is.

1. New Nylon bushings for the clutch pedal to repair mechanics of it and resolve the issue of it not returning to the top occasionally
2. New Nylon bushing attaching push rod on master to clutch pedal lever
3. New clutch kit, everything replaced. (warrantied, if it ever fails again I only pay labor)
4. Service of front diff (drain and fill)
5. Service of Transfer case
6. Service of Transmission
7. Service of rear diff (plate pull full service)

All for just under 1k. The price seems very fair for the work being done. I really like my truck other than the 11 mpg which I trade for the 460 power house so it's money well spent.

Thanks again guys, really appreciate the advice.

 

That doesn't sound all that bad for what all you're getting. My truck does growl in first and second if it's below 1000 RPM, and it might do it in 3rd too if I let the engine slow down enough. ZF/Ford says for hard shifting in cold temperatures to use the synthetic Mercon fluid. I think Mercon V is all synthetic and is the recommended service fluid for the ZF. How many miles do you have on your truck? My dad's 92 had the same issue with the clutch pedal pivot bushings - that must be a fairly common problem.

 

Truck has 138k. I picked it up early this year and it's been solid. This 1k is more than I wanted to put in it but the 460 should be a tank for me for a few more years at least.

I spoke to the tech that will be working on my truck and he said the nylon bushings are termed "self lubricating", the reality is they sacrifice small parts of itself to lube the mechanism and over the years a small bit of wobble will occur.

I am excited to get the truck back to see how well it will drive with the new clutch and all gear boxes serviced and ready for the upcoming pheasant hunt.

 

I was called in by my mechanic today to take a look at the bracket that mounts the clutch and brake pedals to the firewall. You can see by the picture that it's no wonder my clutch operation has been very odd feeling and not returning to the original position. With that much wobble room on the pedal it's no wonder the clutch seemed to engage so low.



You can't get these parts from Ford anymore so they are going to fabricate a solution using a large washer that is slightly thicker than the original metal. They will have to mill out the center of the washer just a bit so it fits the shaft perfectly then weld it into place. They will also be shaving a little bit of the nylon bushing off to make room for the additional width of the washer.

Has anyone else seen this type of oblong wear on the cluck bracket assembly?

The clutch was cooked and the pressure plate had collapsed. I am getting excited to get my truck back and see how much better it drives.

 

Wow that's a lot of wear. Ford must have stopped making those in the past few years because we bought a new pedal bracket when we did the bushings on my dad's truck. The return spring mount had also broken, which was the reason for the whole bracket.

 

Yea I just had the clutch pedal bracket replaced. It's one of those things that shouldn't be white metal, but is- It had an egg-shaped pivot hole. This is fairly common. My mechanic was able to find a NOS one from Motorcraft for me, in lieu of the ransom I would have held him for because he recently failed to tighten 4 of my pressure plate bolts and wouldn't confess.

 

The low RPM growling of the ZF is completely normal. Mine does it like crazy. And it does it at idle with A/C on and the RPM drops to 700-800. And its really loud when i pull it down to 500RPM or so.

EPNCSU2006- have you tried any heavier fluid in the ZF? I am starting to think that ATF is to thin for the ZF. I know they are noisy beasts but it seems like when the trans heats up and the fluid thins out that it really starts making more noise. Maybe 2 QTs of 10w-30 would help lube it better? i might give it a try next time i change my fluids.

 

I just rebuilt mine, so I'm sticking with the Ford spec at least for a while. If you look up ZF oil spec TE-ML 02, they list several gear oil weights as acceptable along with ATF. I would not use motor oil, though, and would not mix two types of fluid. Are you using Mercon V or the older Dexron/Mercon III?

 

How load is yours after the rebuild? Especially when warm? When mine gets warm it sounds like a heavy diesel low end. Its really noticeable if im sitting at idle. And i have to hod in the clutch to order at the drive through. But mine has unknown mileage and history.

I'v been using Mercon V. Ill have to look up the oil specs. I know that the use of ATF is because of the smaller needle bearing in place of larger roller bearings, the idea is that the ATF is thinner and provides better lubrication for the smaller bearings.

There are no problems with mixing oils, or using motor oil, And although the specs differ greatly both are acceptable in this application. However i would not put any heavy oils in the zf, and definitely not 80 or 90 weight.

 

In neutral, the synchro rings rattle a little bit, but there's really not much gear noise at all. I have a slight whine in 3rd and 5th under load, but the gears are quiet otherwise. I think if I had the shift boot and insulator in there that I wouldn't notice the noise at all.

The gear oil info is straight from ZF for the S5-42. I'm not sure what would be different between an S5-42 used in an application other than a Ford truck - there's only one parts list and only a couple of options in it for internals. Is the size of the needles the difference between other manual transmissions and the ZF?