The ATF was used to help get fuel mileage up for gov't standards. One of the reasons why ZF trans life is so short is due to a lightweight oil in it. I will run synthetic ATF on a fresh reman until it is broken in. After that I use Amsoil 30w synthetic. Running 30w Amsoil, I have never had to reman one.

 

ZF trans life short?
I don't think I've seen any which *have* been rebuilt, to be honest... all the trucks I've seen appear to be original transmission, with the wear associated with multi-hundred-K miles(mostly synchro wear). I've got one that probably needs bearings, but it also still runs for now and doesn't seem to leak. (I probably should check the fluid level now that I think about it).

 

When you go to rebuild your ZF you'll agree with me about short life. The synchros are harder than the gears, so if you have bad synchros you have bad gears.
If you use your truck as a "grocery getter" you might see 150K out of the trans. If you work it and pull grossing 20K you'll get 75K.
The Borg Warner 4 spds refuse to die after 300K of hard use.

 

Unless you can come up with some pictures or evidence, I have to take this with a grain of salt.
There are /many/ trucks and people on this forum with the ZF 5-speed, by now just about every IDI has well over 150K on it. The number of threads about rebuilding/replacing ZF-5s? Very few. Even on these topics, it looks like the synchros are the main concern, along with bearings. I haven't read anything about massive wear on the gears.
I'm not disputing that your transmission was worn out quite early; perhaps someone put heavy gear oil in it for some period of time?

The other main issue is that our odometers roll over at the 100K mark... So we only know that a truck has x*100,000 + odometer reading. The X could be 0 , more likely 1-2, or even more.

I wish I could say for certainty that my truck(s) have gone 200,000 miles+ without needing a rebuild of the transmission, but I really can't - While the transmission /looks/ like it hasn't been rebuilt, and the truck /looks/ like it's got over 200K(and I know it has over 120K, having driven it the last 25K), it could have 400K for all I know. The engine bores had enlarged themselves by .020 when I rebuilt it, which seems like a /ton/ of wear to me. But I don't have any concrete numbers, so I can't prove you wrong.

 

Got the fluid in Friday and had the opportunity to take her for a little jaunt yesterday. The MTL has made a noted difference in the smoothness of the gates in first through third (my most problematic gears). It also seems to have quieted down a lot of rattle I was getting when near the governor in third. The syncros are still a bit slow, but you'd expect that with a truck transmission; it's just not meant to be shifted quickly. The MTL was pricey, but seeing how I shouldn't have to redo this job anytime soon and given the results, it seems worth it. BTW, I only filled to fill plug and did NOT add the little bit extra some people do by pulling the shifter and going in that way.

Mike

 

This is what zf says should be the correct stuff.
http://www.zf.com/media/media/docume...uid_M_EN~1.pdf

I think I will try this one

Castrol Manual EP 80W
Převodovũ olej pro manuální převodovky
Popis
Castrol Manual EP 80W je minerální olej vhodnũ pro použití tam, kde je požadován převodovũ olej klasifikace API GL-4.
Castrol Manual EP 80W je schválen pro převodovky Mercedes-Benz, které jsou používány v lehkũch užitkovũch a
nákladních automobilech. Rovněž je schválen pro použití v manuálních převodovkách ZF.
Vũhody
Široká možnost použití díky četnému schválení od evropskũch vũrobců automobilů.
Vysoká termální stabilita chrání vůči tvorbě úsad a zahušťování oleje, což prodlužuje životnost a zlepšuje
vũkonnost oleje i převodovky.
Vũborná schopnost ochrany vůči opotřebení a schopnost přenášet zatížení prodlužuje životnost jednotlivũch
součástek převodovky.

Typická charakteristika
Manual EP 80
Viscosity 15 °C ASTM D1298 g/ml 0,883
Viskozita, kinematic at 100 °C ASTM D445 mm˛/s 9,9
Pour Point ASTM D97 °C -30
Viskozita, Brookfield při -26 °C ASTM D2983 mPa.s (cP) < 150 000
Viskozita, kinematická při 40 °C ASTM D445 mm˛/s 94
Viskozitní index ASTM D2270 - 97
Bod vzplanutí, COC ASTM D92 °C 180
Vũkonnostní specifikace produktu

API GL-4
MAN 341 Typ E1
MAN 341 Typ Z2
MB-Approval 235.1
ZF TE-ML 17A



It is in czech, but the data is obvious and u can use google translate but nothing realy that interesting.

Or this one.
Castrol Syntrans Multivehicle 75W-90
Manual Transmission Fluid
Description
Castrol Syntrans Multivehicle 75W-90* is a full synthetic manual transmission fluid recommended for most manual
transmissions where API GL-4 lubricants are required. It has been successfully used as a problem solver for low
temperature shiftability issues in the manual transmissions of a number of manufacturers.
Advantages
Excellent synchroniser performance giving extended synchroniser life and shift comfort.
Exceptional cold flow properties giving smoother gear shift at low temperatures.
High shear stability giving a constant viscosity during oil life and noise reduction.
Excellent thermal and oxidative stability for transmission cleanliness and longer oil life.
Temperature reduction in operation prolongs the life of lubricant and aids fuel efficiency
Typical Characteristics
Name Method Units Syntrans Multivehicle 75W-90
Viscosity, Kinematic 100C ASTM D445 mm˛/s 15.09
Viscosity Index ISO 2909 None 195
Viscosity, Brookfield @ -40C DIN 51398 mPa.s (cP) 20000
Viscosity, Kinematic 40C ASTM D445 mm˛/s 76
Density @ 15C DIN EN ISO 12185 g/ml 0.873
Pour Point ISO 3016 °C -51

Product Performance Claims
API GL-4
Ford WSD-M2C200-C
MB-Approval 235.72
*SAE Class according to J306 pre 1998

For some reasons the pages could not be posted so I just copied it, sorry fr the mess.

 

List of lubricants - ZF Friedrichshafen AG

 

I'm not trying to make this a pissing match so please don't take it that way.
I just remaned a ZF -5 for my secondary truck. It has 212K on the odom. I didn't want a good trans in my secondary truck so I pulled a working trans out of my primary truck and put it in the secondary truck. The working trans truck has 176K on it, I don't know if the trans has ever been rebuilt. The remaned trans then went into the primary truck. I got new gears thoughout the reman trans because I wanted a "gas" gear set. With my back-hoe on the gooseneck I gross 25-26K. Starting on level ground required me to start in the Low range, go thru all 5 gears, move the trans to N, move the transfer case into Hi, then move the trans into 2nd and go thru the gears again. The gas gear pack has a lower first and second and hopefully will prevent that (I haven't towed with it yet). The gears in my trans were worn and when trying to locate a gas set I was told that usually the gears need to be replaced because the synchros are harder.
Trying to find a ZF in a salvage yard here is an effort in futility - there are none. It might be that every cowboy out here has to prove that he has a big genitals and tries to pull a 6 horse trailer up a 8% grade at the same speed as the mini van in front of him can. I don't drive that way but it seems 80% of the P/U owners out here do. When the cowboy starts to fall back, he drops another gear and floors it. Not only is this bad on fuel economy but it is hell on a trans and diff. This might be why there are no ZF's in salvage yards and why their life is considered short. I bought all of my trucks used and I'm sure this is how they were driven before my name got onto the title.
If you drive it like a civilized person, life might be long (relatively). However I don't ever see a ZF outlasting a Borg Warner.

I was told by a tow truck owner, that went thru ZF's every other year, that after he switched to 30w in his ZF he never had a problem with it. After I get 10K on my trans I will switch to 30W Amsoil.

 

I'm thinking you need more power out of that engine -- either a tune up or turbo or both.
I just hauled 16,000lbs+7K truck weight = 23K gross with a bumper-pull setup, and I had no trouble at all starting in high range 1st. It took a while to get up to 50 though, which was all I felt safe doing with that.

I don't see why... if you have sufficient lubrication, the transmission shouldn't mind too much(it's rated at a given input torque, throughout all the gears).
Differential, well, yeah, you're going to be putting more torque through it. But that's kind of the point of having a truck, isn't it? And, same deal... If you have good oil in it, it shouldn't cause undue wear.
Also remember that our IDIs were designed to be run up against the governor for hours on end, and NA, you aren't going to be making much HP at all until you get it up in the 2500 RPM range... even more important with a turbo.

Full-synthetic oil shouldn't hurt; I looked up the specs on 10W-30 Amsoil and it looks a bit thicker than synthetic ATF... but not extremely thick.
30W is probably close enough to be just fine if not better... 75W I don't think is a good idea.

 

The truck has an ATS turbo, but it also has 3.55 gears. I'm also at 5100' in elevation. You might be right about using the higher RPMs. I usually don't. My driving habits come from A LOT of time behind a Detroit 60 Series. Low RPM (1200-1500), use the torque not the HP. V-8 designs usually don't produce the torque that an in-line engine will, their asset is in HP.

The cowboy hammering up a hill moves the stick as fast as he can and gets back on the fuel hard, rather than rolling into it. I don't know if a 10W ATF protects against that kind of shock load. He must be a good driver though, he does all that between sips of his Budweiser!! :-)

 

Sounds to me like you'd be happier with 4.10's towing that load. That and pushing the rpm's higher before shifting and you'd do a lot better with that load.

 

Yeah, my secondary truck has 4.10's and an ATS turbo, but still seems sluggish pulling anything. The fuel pump might not be turned up enough or the engine might be worn out. I love the 21mpg of the 3.55 gears vs the 17 mpg of the 4.10 gears though. (Those are unladen fuel efficiency numbers).

 

Ouch. That gearing will kill you torque wise; great for highway, not for towing.
How did you get 3.55 gears anyway? I thought 4.10 was standard gearing behind a 5-speed?
Double ouch.
N/A, this engine has a pretty flat torque curve up to about 2K RPM, where it starts dropping. HP hits a peak at 3K.
With a turbo, it's a whole different ball game.
Banks Power | 83-93 Ford - 6.9 & 7.3L>>SidewinderŽ Turbo System (click on proof for graphs)
Those are banks's quoted numbers and graphs, but they didn't max out the IP, so the high end is weak. My own numbers(see signature), gave me a torque peak around 2600, and a HP peak around 2800(at 2K elevation). So don't be afraid to run this engine in the 2500-3K range; it's right up in it's power band... and you need the speed to get your turbo to spool nicely.

Oh, I see what you mean. Yeah, that can be a bit hard on things.

One thing I wonder abut is ambient temps and trans temps -- cold, I'd expect ATF to do better, but if you are in a California summer and get a lot of heat out of the transmission... the extra thickness shouldn't hurt.

 

3.55 and 4.10 were standard behind both trannies. Not sure what was _commonly_ put behind the IDI 5-speeds, but our two ZF5 PSDs and our T-19 IDI all have 3.55s.