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What oil to run in my ZF gearbox?

G Guest
I've spent hours reading everything I can find about what oil is best for the ZF gearbox.

I read the GL5 oils are bad for the "yellow metals" in the transaxle, and I've been told there are no "yellow" metals in the ZF, unless rebuilt with cheap parts.

The box was rebuilt by a reputable builder, I know this, with an extra tall 5th gear installed so freeway cruising is not buzzing the engine. I forget the name of the company but it's 3 letters like RBT or something.

I want to run the best oil I can get for my new ZF box.

I've been told "any good 90 weight is fine", I've read about people running the Castrol Hypoy C GL5 that one of the reputable builders here recomends. I found that but it was like $33 a quart (maybe a misprint?).

I've read about people using all the different Red Line offerings, "Shock Proof Medium", "Shock Proof Heavy", and Red Line "MTL".

I found Brad Penn who makes an 80-90 GL4 non-synthetic, that is probably first in the running, my local shop can get it in a day or 2.

I know I might be opening a can of worms here, because the more I read, the more different answers I get.

I'm OK with switching to synthetic, but I've read if you use too slippery of an oil, the synchros don't grab enough, and don't slow the gears down between shifts and cause shifting issues.

SO, my first inclination is to run a non-synthetic GL4 formula oil, probably the Brad Penn (I know Brad Penn is good stuff).

If the GL5 thing doesn't matter, I'd love to run Swepco oil in my gearbox, but it's GL5, so I'm hesitant until I get solid advice or information/proof that running GL5 has no negative effects. I know Swepco is REALLY good stuff, from my Porshe racing days.

I've asked 10 different people and gotten 10 different answers, so I know if I run Brad Penn 80-90 GL4 non-synthetic, I should be fine, but I'd like to hear what others have to say.

My ZF gearbox is very dear to my heart now, and I want to run the best oil I can run in it.

IF, there's no issue with GL5, is there any advantage to running the Red Line Shock Proof heavy or medium? The "Shock Proof" part sounds like it might be a good thing to run, if that's what it does. I don't plan on beating on this box very hard, so again, probably any 90 weight would be fine, but I'd like to hear what others think about the subject.

Thanks for any help or advice,

Mike
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jfb05177jfb05177Member
quote:
Originally posted by mike the snake:
...The box was rebuilt by a reputable builder, I know this, with an extra tall 5th gear installed so freeway cruising is not buzzing the engine...


DO you know what 5th gear ratio was installed? Do you think they also changed 4th to even out the shifting rpm droop?
and finally, what rpm are you running at 70MPH?

As for which lube, I'll just wait till Ron tells me what he put back in mine Smiler
George PGeorge PAdmin.

The gearbox lubricant needs to satisfy the requirements of a limited slip differential, the "spiral-bevel" ring and pinion gears, bearings of all types, transmission gears and the synchronizer rings. The lubricant must also be non-corrosive to the metals used to manufacture the various parts within the gearbox.

ZF's original recommended gearbox lubricants had viscosity ratings of SAE 80 or SAE 80W90, and an API GL-4 rating. Castrol 80W90 Hypoy Gear Oil (rated GL-4) was among the lubricants ZF originally recommended to Ford. GL-4 lubricants are medium load lubricants in which the additive package has been specifically formulated to meet the requirements of limited slip differentials and synchronizer rings, while being non-corrosive to aluminum and yellow metals. API GL-4 lubricants are common lubricants for transmissions and transaxles.

Some guys have good luck with synthetic oils, others find the synthetics tend to leak (drip) from all the seams between castings and from the seals, in those cases the owners have returned to petroleum based oils, and the leaks stopped leaking.

Last edited by George P
lf-tp2511lf-tp2511Member
quote:
hypoid ring and pinion gear sets (such as the gear set within the ZF 5DS-25

I have come, after doing oil research some months ago, to believe the Pantera ZF is NOT a hypoid ring and pinion style.

All I know is what I read.

Can anyone add some clarity to this?


Cutaway of our ZF - note the pinion and ring gear centers are on the same plane, not offset:

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George PGeorge PAdmin.



Larry, nothing personal. Honest. Forgive me just the same. My concern is that I'm already behind on forum clean-up.

This topic should remain focused on the lubrication needs of the ZF, i.e. the OP's original question.

A new topic in regards to Larry's point may be educational for all of us. It seems Lloyd could answer this question quickly.

Last edited by George P
lf-tp2511lf-tp2511Member
Nothing personal George, but the topic of hypoid versus spiral bevel is not a thread hijack when discussing the needed gear oil in our ZF transaxles.

The forces found in an offset (hypoid) R&P are greater than those in a spiral gear R&P, and thus the two styles have different lubrication requirements.

I'm posting the RBT FAQ Andy refers to.

I only know what I read.

Larry

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davidnunndavidnunnMember
George,

It seems that new Pantera owners (and some of us long-time owners) are looking for specific gear lube recommendations, as opposed to reading debates on whether to use GL-4 vs. GL-5 and to a lesser degree synthetic vs. mineral based gear lube. As far as the synthetic vs. mineral based oils are concerned, Lloyd Butfoy says synthetic based oils are fine to use but the ZF might leak a bit when using them. Lloyd told me, even brand new or freshly rebuilt RBT's (ZF's) can leak a bit when using synthetic oil. In these cases, some will stop leaking after a period of time, when the gaskets "swell up". The only real benefit to synthetic oil, in a street driven Pantera, is the ZF may shift a bit better.

Oddly enough, the specs in our owner's manual calls for GL-5; however, I have always believed that to be a misprint or a typo. I'll take RBT's recommendation over DeTomaso's without hesitation!

As mentioned in previous postings, it's vital that the oil is changed in a ZF once per year. The reason for this is, condensation tends to form inside the ZF's case.

Here are a few gear oil recommendations. All of these oils are safe to use in our transaxles:

Redline MT-90. This is a synthetic, GL-4 gear oil, 75W90.

Redline 75W90-NS. This is a synthetic GL-5 gear oil but without the friction modifiers for hypoid gears, common to GL-5 gear oils.

Brad Penn (formerly Kendall) Classic. This gear oil is a mineral based GL-4, 80W90.

I hope this helps.
R 1Rocketship (Guest)
Just a thought...If given time when using synthetic gear oil, the gaskets will "Swell Up", would pre-soaking the gaskets in the synthetic gear oil help eliminate the initial leaks/ing ?.

On aside note, I would Definitely use the gear oil recommended by a ZF transmission specialist like RBT, as patently obvious their experience & expertise is unmatched in the industry...Mark
R 1Rocketship (Guest)
quote:
Originally posted by mike the snake:
I inquired and Roger did the gearbox himself, using parts and seals and the tall 5th gear from RBT.

The box is butter smooth right now, but I have no way of knowing if Roger used brass synchros or bushings, so I'm going to stick with a GL4 oil.
Hello Mike; I would suggest with a great deal of confidence, that if you spoke with RBT & referenced Roger's name along with the serial number of your ZF, that chances are very likely that RBT has the invoice & parts list of Rodger's order that would determine what type of syncros were ordered/installed.
MT mike the snake (Guest)
Ahhh, GREAT idea!

Thanks for the tip.

The group of Pantera people I'm meeting and talking with are all he nicest, most helpful bunch of people.

I appreciate the tips.

Thanks again.

Mike



quote:
Originally posted by 1Rocketship:
quote:
Originally posted by mike the snake:
I inquired and Roger did the gearbox himself, using parts and seals and the tall 5th gear from RBT.

The box is butter smooth right now, but I have no way of knowing if Roger used brass synchros or bushings, so I'm going to stick with a GL4 oil.
Hello Mike; I would suggest with a great deal of confidence, that if you spoke with RBT & referenced Roger's name along with the serial number of your ZF, that chances are very likely that RBT has the invoice & parts list of Rodger's order that would determine what type of syncros were ordered/installed.
O osofastMember
Hi Mike I haven't welcome you to the forum yet so welcome to our addiction.
I am a big fan of synthetic lubricants and a very big fan of Redline products. I love how they work and what they can do. It is amazing how well this oil works, from reducing gear mesh noises, to ease of shifting when this oil is used. Also from how "thick" the HeavyShok is you will not experience any leaks that others have reported from the ZF with other brands of synthetic oils.
I would recommend that you change the oil in the ZF yearly to.
Jeff

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panteradougpanteradougMember
quote:
Originally posted by 1Rocketship:
quote:
As soon as I put it in, the shifter felt tight and new.


"As soon as I put it in, the shifter felt tight and new".



HEY Doug!!!...You are talking about the ZF transmission right??!! Yeah Baby!...Mark


Yes. Hall recommended I try this stuff 20 years ago. Maybe 15, before I tore the ZF apart.

It had the effect of tightening the feel of the shift mechanism and certainly quieted the second gear grind to not being there.

Even if it doesn't work for you and you have to change the synchros, at least it is worth the shot at about $50 vs. the cost of new gears, synchros and whatever else.

I think it might have a particular component of a friction additive that even though it is synthetic and therefore slipperier than dinosaur remains, the synchros seem to like it?

I'm thinking that maybe the original formula of lube was miss prescribed, or maybe just that's all there was back then? I don't question it. Just a suggestion to those who are changing their trannie lube now.

Do whatever you feel appropriate. I'm not making any money on any of this stuff. I have no dog in the hunt.
MT mike the snake (Guest)
Well, SHOOT!

I just went and found and bought 4 quarts of the Castrol Hypoy 80-90 GL5 that RBT and others suggested, but I was also very interested in the "Shock Proof" medium and heavy Red Line offerings as well.

Just wasn't sure if I wanted to switch to synthetic, or just go with what the old-schoolers suggested.

I found "Brad Penn" 80-90 GL4 too that was also in the running, I know Brad Penn oil is good stuff, at least their engine oils are.

My gearbox shifts as smooth as butter right now. My guess is it probably has the Castrol in it now.

Of course I want to keep it that way, but I do like the idea of running the Red Line Heavy Shock Proof, if it has some advantage over the Castrol or Brad Penn Dino oils. I like the sound of running a heavier weight oil, but I don't know if that would be better or not.


Then there's the Red Line MTL oil as well that has also been suggested.

I still have time, I can return the Castrol, and get any of the other brands discussed here.

Hmmm, decisions, decisions.
MT mike the snake (Guest)
I wish I was able to feel other's shifting, so I could compare my shifting, and how it feels compared to others.

I'm a smooth, methodical type shifter, not a speed or jam shifter, just smooth and easy and consistent. I find if you try to shift too fast some gearboxes aren't happy with that.

That said, my box shifts into every gear smoothly, no nicks or grinds, but I feel an overall stiffness through the lever, like the shaft needs lubrication. That's my only complaint (not really a complaint) I just feel that once I get in there and lube the shaft bushings things will feel better.

I may try the Red Line offerings, just to see how they feel. If I don't like it I can always switch back to non synthetic.

Seems though like now now I have a number of confirmed "This will work OK in your ZF" gear oils to choose from.

Which brand I end up will probably be as big a surprise to you as it is to me, but, like I said, maybe I'll just try all of them and see which one I like best.

Thanks for all the tips and information.
4nhotrod4nhotrodHe who dies with the most toys is dead
quote:
Originally posted by OSOFAST:
Hi Mike I haven't welcome you to the forum yet so welcome to our addiction.
I am a big fan of synthetic lubricants and a very big fan of Redline products. I love how they work and what they can do. It is amazing how well this oil works, from reducing gear mesh noises, to ease of shifting when this oil is used. Also from how "thick" the HeavyShok is you will not experience any leaks that others have reported from the ZF with other brands of synthetic oils.
I would recommend that you change the oil in the ZF yearly to.
Jeff

Re: Heavy Shockproof:
In the details, doesn't it say " not recommended for most synchro applications" ?
Our ZF's have synchs, no? Am I missing something here?
MT mike the snake (Guest)
No, you're not missing anything. I confirmed that the shock-proof oils are not to be used.

Red Line makes a 75-80 MTL and an 80-90NS that are both supposed to be compatible, so those are my options for synthetics to run.

I already bought 4 quarts of the Castrol Hypoy gear oil reommneded by RBT, so I have that to possibly use.

I found Brad Penn 80-90 GL4 conventional oil that fits all the requirements. I know Brad Penn motor oils are some of THE best dino (non synthetic) oils available.

If I knew for sure that GL5 was OK to use, then I'd also be considering Swepco, because I know Swepco is another one of THE best non synthetic oils available, but their gear oil is GL5.

So it's down to Castrol Hypoy 80-90 GL5, Red line MTS or NS, or the Brad Penn 80-90 GL4.

My shifting is smooth as butter, but very stiff, as if the shaft or shifting mechanism or shaft is dry or not lubricated.

Early next week I'll have the car on a lift, and be able to get under and lube everything and change out all the fluids, which I'm sure will imrove the feel of the shifting.
bosswrenchbosswrenchMember
Mike, check to see if Roger took out the redundant shifter interlock behind the shift-stick in the cabin. Its under a snap-ring retained plug (under the small rectangular upholstered piece on the console) and consists of a 2" long steel plug with a detent-tip & a spring. The ZF has a second detent inside the box and often the external one gums up so the two do not work in unison. Remove it & put it on a shelf with a cork in the hole, then try it this way. Other external things that slow shifting are partially seized shift-rod u-joints and a stuck or misaligned shift-shaft johnny-joint below the left header.
MT mike the snake (Guest)
Thanks,

I'll check that out.

Made the decision today, and bought 4 quarts of Red Line MT90. We'll see how it feels. Aint no thang, I can just keep swapping out oils and find the one I like if this stuff doesn't work out.



quote:
Originally posted by Bosswrench:
Mike, check to see if Roger took out the redundant shifter interlock behind the shift-stick in the cabin. Its under a snap-ring retained plug (under the small rectangular upholstered piece on the console) and consists of a 2" long steel plug with a detent-tip & a spring. The ZF has a second detent inside the box and often the external one gums up so the two do not work in unison. Remove it & put it on a shelf with a cork in the hole, then try it this way. Other external things that slow shifting are partially seized shift-rod u-joints and a stuck or misaligned shift-shaft johnny-joint below the left header.
MT mike the snake (Guest)
Red Line MT90 feels REALLY good in my gearbox.

It already felt good, but I can say now it feels even better. Shifts smooth as butter.

I need to keep spraying lithium grease on that little shaft guide half-way back to the box though, when it dries out the shifting starts to feel draggy.

Finally, after putting another hour of driving on the car (total of 3-4 hours) I'm really starting to enjoy my new car!
panteradougpanteradougMember
That thread refers to "shooting the rod" with dry teflon lubricant "before every drive".

If that is necessary, than that is not the part you want.

The part I posted has a permanently dry lubricant embedded bushing installed into it.

That's really what you want there. If you don't like the glitz, spray it black. They come black too. Anodized. The part is machined out of aluminum billet.
I insaneMember
Hi Guys.

Im also stuck in this jungle of different ZF oils. =)

But for me it has come down to just two different
oils and those are:


Redline MT-90

Or

Redline 75W90-NS


Im leaning towards MT-90 because its a GL-4 oil and the Mike the Snake
that started the thread seems to be very pleased with that oil.

The ZF in my car has never been rebuilt but works perfect but i
feel a oil change is due because i bought the car 2 years ago and
i dont Think the previous owner has changed it for quite some years.

If you "Mike the Snake" also read this then i want to ask why you
Went with MT-90..?


Sorry for bad Spelling guys but im from Sweden. =)


Best Regards
Peter
W wasatchcatMember
Here is another option, a little expensive, but works extremely well for me, especially in cool weather. The data sheet has the applications and specifications for both their GL-4 and GL-5 offering. I run, and am suggesting, the GL-4 for the ZF. It is harder to find, but can be shipped from on-line vendors.

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jag13catjag13catMember
NEO 75w90 Gear Oil --- Has anybody used or is anyone familiar with NEO 75w90 Gear Oil (synthetic)? With the recent purchase of a Pantera, the ZF, still in the crate after being rebuilt through one of the California vendors, was shipped with a gallon of the aforementioned gear oil to be put in the ZF. I am not familiar with it.
lyall6007lyall6007Member
First post... New owner and gear oil change time...

Blue #6007 moved from SoCal to Seattle February, 2016. Hall Pantera did a full restoration in 2002 for my Dad and Tom Hodges built the "street mini brute" motor. Tom continued to service the car until it's trip north.

I spoke with Tom in February about the car, engine & gear oil preferences. He told me to use NEO synthetic 90 weight, iirc. JAG13CAT's post above is the first mention of NEO.

Anybody else using this?

*********************************************

Update: I called NEO oil and spoke with Paul. They do specialty oils and custom blends. Paul said when he was a teenager he use to deliver cases of NEO 75w90 to Gary Hall. It's all they ever used in the ZF.

They make an F1 oil and several BTC teams are using their new 10w60 racing oil along with a few WRC teams.

Just bought a gallon...

Lyall

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