zf 6 info

[psduser1]

Alright guys, looks like I'm going to go through this thing pretty soon. Anybody have any uogrades, better parts, slick tricks, anything to help with durability?
This tranny has 200k, and it gets used...hard! I've went to a decent dual disc clutch, and it gets oilchanges routinely, abou every 30,000 miles, with mercon.
I know heat is killing it, as I'm often pulling 14k, often considerably more, on a hot street setting, realistically 275-300 hp.
Has anybody rigged up an external cooler, I'm assuming that I'd need to setup a smallish external pump of some sort?
Just trying to get some ideas at this point, and I would appreciate any input.

 

[IDP]

They have a pump and external cooler already. My advice is to buy a reman from midwest gear or somebody like that. It comes with a warranty and youll have a hard time buying parts to fix yours for less. Also theyre a pita to do lots of parts and press time getting them apart.

 

[psduser1]

Pretty sure my 00 doesn't have an external cooler, I've had it out before. Hadn't looked at remans, that is an option, tho. Mostly, I'm wondering if there are ny better hard parts,etc.

 

[Charles]

Yes it has a cooler, that's what those cooler lines are for... If you removed the trans then you either drug them out from under the truck until you ripped them in two, or you unhooked them...


On my 550 I added another cooler in front of the radiator inline with the OEM cooler that's in the radiator, and I dropped my steady-state speed from 70-75 down to ~65 or so. I don't know if it will make it hold, but this coming hay season will probably tell the tale.

Other than that.... put an auto in it, or drive like a grandpa, cause the ZF is a joke for heavy towing.

 

[Petro]

Charles, do you have a trans temp gauge for your ZF 6? If so, what temps are you seeing loaded and unloaded ?

 

[psduser1]

Charles, I've torn apart a lot of stuff, pretty sure I know what cooler lines look like. I appreciate your insight, but this one does not have a cooler!
I think we use these trucks in a similar manner, and I've read your posts with interest because I've seen a lot of similar things, albeit at lower hp levels. Ten, 15, 30 hrs with 15k at 68-72 miles takes it toll. Summertime, it sees 18-20k at a time, with shorter duration, 2-4 hrs.
I will have to see what I can find for stock parts, but it doesn't sound like that's gonna get it.

 

[bfife]

I'm a fulltime RV'er. so I tow heavy and a lot. The trailer weighs right at 18,500. My stock tranny died at 160K. I replaced it with a MidWest Tranny custom unit. Dan built me a ZF6 that fits a 7.3 but has the input shaft for the 6.0. 1 in pilot shaft instead of 5/8. It required a modified flywheel to accept the 6.0 pilot bearing. I also went with a South Bend DD clutch. I also installed a Dieselsite tranny cooler/filter. Temps stay around 25-50 degrees above ambient temps. and cool down to ambient within 10 minutes of idle. I also installed a Fastcool cooler. Its a housing that bolts on in place of the PTO cover. adds about a qt more capacity. works well for me.
Barney

 

[Charles]

Charles, I've torn apart a lot of stuff, pretty sure I know what cooler lines look like. I appreciate your insight, but this one does not have a cooler!

So....

The ports in the side of the trans where the fluid goes to and from the cooler....

Just what exactly do you have going on there? Pumping fluid out on the ground until it stops pouring out or what? My truck was built in march of 1998 and it had the exact same radiator bottom tank cooler and lines as every other superduty on planet earth. Your 2000 had a whole year or more to get the same parts.

If there is NO cooler, then that trans doesn't stand a chance in HELL. Although I would love to know what exactly you're doing with the pump ports in the trans case if there are no cooler lines hooked to them...

 

[Charles]

I'm curious as to what's happening here:

And here:

I mean, if you don't have any of that.... is there some gasser trans without a pump or something? Did someone swap in a ZF5? Do you have 6 forward gears??? LOL

Does the radiator not even have the ports???

Does the tag in the door say "Manufactured on Mars" by chance???


Point being.... until we nail down just exactly what you've GOT.... it might not make sense to spend much time trying to figure out the next step.

 

[Charles]

If you get your lack of cooler issue resolved, I would add an air:liquid unit in conjunction with it.

I bought a cheap one and did this just to try and help the poor thing live:

I would also take the suggestions from Bfife seriously. Although shaft sizes and such I don't see being a necessary step unless that shaft allows for a stronger bearing set or something. The hard parts themselves aren't in jeopardy when towing, it's the heat shedding ability that's insufficient.

 

[Charles]

Charles, do you have a trans temp gauge for your ZF 6? If so, what temps are you seeing loaded and unloaded ?

I don't have a gauge. My gauge is black, scorched trans fluid that's only a few thousand miles old. I'm hoping I won't see that again so bad with the added cooler.

I would like to know if Bfife took trans temp readings with a stock trans before he added the stuff that he did.

 

[Petro]

I don't have a gauge. My gauge is black, scorched trans fluid that's only a few thousand miles old. I'm hoping I won't see that again so bad with the added cooler.

I would like to know if Bfife took trans temp readings with a stock trans before he added the stuff that he did.

Post back on weather the extra cooler helps, I'm very interested to see what it takes to hold a Zf together while towing heavy with some decent power.

 

[psduser1]

Ok, I'm officially retardedointlaugh::doh:

Got off my a$$, went and looked, you guys are right.



Anybody tryed an auto tranny cooler? Heavier oil, maybe some 80w90?
I am going to call midwesttrans today, and ask them some questions.

 

[bfife]

If you get your lack of cooler issue resolved, I would add an air:liquid unit in conjunction with it.

I bought a cheap one and did this just to try and help the poor thing live:

I would also take the suggestions from Bfife seriously. Although shaft sizes and such I don't see being a necessary step unless that shaft allows for a stronger bearing set or something. The hard parts themselves aren't in jeopardy when towing, it's the heat shedding ability that's insufficient.

That's why Dan does the hybrid. The 6 leaker input shaft uses a huge roller bearing for the pilot bearing, instead of the POS bearing the 7.3 has. You must machine the flywheel to accept it. I did add the trucool cooler from Bob, plus the added capacity of the FastCool.

Barney

 

[2000wa250]

So Barney,

What's the benefit for this input shaft other than the beefier bearing? Does it help with transferring power? How much machine work are we talking? Will a southbend dd still work? I kinda think my synchros are starting to go out so gathering options for rebuilt or replacement of my zf-6 if I decide to stick with it.

Sent from my DROID BIONIC using Tapatalk 2

 

[bfife]

To answer a couple of questions;
no I didn't take any pretemps before I added the cooler and extra capacity housing. I did all this when I replaced my tranny back in 2011.
One of the week spots of the 7.3 tranny is the pilot bushing. I had replaced mine, then replaced it again with one of the Kevlar units and then it was time to replace it again when I talked to Dan about the 6 leaker option.
You would have to ask Dan about the machining. I just ordered the DD clutch and flywheel when I ordered the tranny.
I do wish the clutch was quieter. I hate sitting at a light with my foot on the pedal. People keep looking around to see what's going to fly out from under my truck

link to the coolers:http://fastcoolers.com



Barney

 

[Charles]

Fwiw, I've never pulled a ZF6 that the pilot bearing wasn't annihilated. And it's not from the install.

I don't however understand why the flywheel couldn't be relieved to add a larger bearing while retaining the same ID of the 7.3 input shaft.

 

[co04cobra]

Southbend seems to have switched to a kevlar bushing instead of a pilot bearing now. At least the last 3 or 4 clutches I have did were like that.

 

[psduser1]

I talked to Dan at Midwest, and his first recommendation was the 6.0 input shaft. We also discussed the output shaft, but in my application decided it wasn't really necessary- much fewer problems associated with that end.
The 6.0 input is 1", the 7.3 is much smaller, as well as the difference in style. The 6.0 liter input option was about a $300 additional charge, pretty reasonably priced compared to the price of a rebuild!

Sounds like that's the first place, aside from cooler size, that has problems. Probably why my trans howls so loudly. LOL

 

[psduser1]

Alright, been a while since I started this thread...update.
I had my old 6 speed torn down for a rebuild. As I was told here, the regulator had come apart. That is part of the front case half, and not rebuildable. My guy called several places, no new case halves were available, and the list price was about $650. No good.
So I called Midwest back, and ordered a reman unit from them.
They were prompt and very helpful for me, and answered all my questions!

Yesterday, the tranny arrived as promised. The only problem I had, and its both mine and their fault , is that we did not discuss my clutch setup! Apparently, this clutch /flywheel setup uses a "303" style roller bearing, which is about 30% larger than the standard 7.3 pilot bearing, o.d. Now, Midwest sent me a replacement needle bearing, standard od, with a larger I id to match the input shaft, which they had sleeved .
Once we figured out what I had, the only solution from their end was to return the case, and they'd change the shaft out for a new one, which would allow me to run the larger roller bearing. Incidentally, the one I have is only a year and a half old, and already trashed.
I don't have another three days to drive to mn, get the shafts swapped and drive home!
After talking to Scott at Midwest, and my clutch guy here at home, we decided to use an Oilite bushing machined out to fit the existing input shaft. Scott assured me that it would not void the warranty on the transmission, and in fact agreed that it would probably outlast the needle or roller bearing setup. We'll see. I've had at least 3 bearings in this truck in the last 80k miles, so that shouldn't be hard to beat!

Since I am to dumb to figure out how to post pics on my phone, I have some up on instagram, same user name.