RBT ZF Fluid Replacement

[Jeffrey]

A few questions for those that have done it before so I don't screw it up....

Can you advise on where exactly the fill plug is for a RBT ZF? Is it the large plug on the right hand side?

RBT recommends 2.5 liters of trans fluid. Do you just put in the 2.5 liters, or is the fill plug on the side also a fluid level indicator?

Hints and tips greatly appreciated.

Thanks,

- Jeff

 

[DaveM]

Jeff the fill plug is on top under the exhaust. It sticks up an inch or so. 2.5L sounds right, but I would measure your old fluid level (from the top of the fill hole) and just refill to that level.

 

[Jeffrey]

Thanks Dave, I did see the large fitting on the top, but sort of figured maybe the plug on the right side is some sort of fluid level indicator. I put an email to Lloyd as well - see if I get an answer. The only problem I see with your approach is if the fluid level is wrong right now - not that I have a reason to think it is. If I don't hear back from Lloyd, I may do a combination of measuring the level as you suggest and also measuring how much drains out.

- Jeff

 

[Steve]

I know this has been addressed in some thread, but what is the recommended oil for the RBT ZF?

 

[DaveM]

I know this has been addressed in some thread, but what is the recommended oil for the RBT ZF?

Lloyd says use 80-90W GL-4 dino oil. He says avoid GL-5 spec oil as it doesn't work with the synchros as well. A little harder to find, but NAPA has some as well as Brad Penn oil.

 

[Rick Muck- Mark IV]

Info here: http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/45485-proper-zf-gear-lube.html

 

[Jeffrey]

Thanks Rick, thanks Dave,

I've read through all the forum posts, Pantera forums, and other sources. None seem to be clear on exact fill procedure. Is the plug on the side used to verify level, or do you just put in 2.5 liters in the top plug and be done with it? I'm thinking the latter, but these RBT's aren't exactly cheap so was hoping for a little verification

- Jeff

 

[DaveM]

Looking over old posts Mike Drew (Pantera owner) says the side plug is only used for the upside down Pantera orientation. It is not relevant for GT40's. The GL-4 oil at NAPA is Sta-Lube by CRC.

 

[Mike]

I run 75-90 Royal Purple Synthetic Gear oil with no bad luck which I'll assume is good luck. This oil was recommended by my installer. There is NO site plug. 2 3/4 quarts is good. I have put all three quarts in and had drain a little because of blow by past my breather and was told 3 quarts is just a tad too much.

 

[Tim Kay]

......... There is NO site plug. 2 3/4 quarts is good. I have put all three quarts in and had drain a little because of blow by past my breather and was told 3 quarts is just a tad too much.

What Mike said^
I suggest fill till you get blow by then take out a half a cup at a time until it stops. Then your next oil change measure what you drain, keep in mind some remains in the trans.

 

[Daryl Adams]

The ZF dash1 in my Mangusta has a fill plug on its tail casting. You fill through that opening until oil runs out and it's full. I've been thinking of using that datum line to make a dipstick to measure the oil level in the "new" ZF in my Superformance. (That assumes that the casting geometries are identical.) Seems like something that should be verified with Mr. Butfoy.

 

[Jeffrey]

Thank you all for the input! - Jeff

 

[Sam Watson]

Jeff, just to answer your original question, you can certainly fill from the right side plug. You just can't use it as an "overflow = full" indicator like a Pantera owner would. You'd end up with a gallon of fluid in there. As long as you measure 2.5L as you pour it in, you are ok.

The only other place to fill the RBT is the top cover vent plug. If that is accessible on your SPF, then you can also fill there and then take your engine dipstick and use it to get a level. Just drop it in till it bottoms, then remove and read the level (after you put the 2.5L in, of course). On my car, this is obscured by the muffler.

CAV180 has been blowing gear oil out the vent tube, so like some other owners, I have added a catch can. Right now it does not have a flow back capability. I'm still experimenting with the location, but the current version is shown in the photo below.

Just drained the Royal Purple synthetic that Olthoff installed and replaced with dino Brad Penn. I was having some syncro issues with 2nd gear. This seems to have gone away with the dino oil. Just FWIW, one person's experience. It's green, by the way, so you know what it is on the garage floor.

Sam

 

[Jeffrey]

Thanks Sam - some great insight there. I like what you are trying to do with the catch can. The top plug is slightly obstructed by the megaphones, but I think I can work around it. I also just ordered the Brad Penn stuff. Will be doing a flush and replace at the end of the week.

- Jeff

 

[Mike Drew]

Looking over old posts Mike Drew (Pantera owner) says the side plug is only used for the upside down Pantera orientation. It is not relevant for GT40's. The GL-4 oil at NAPA is Sta-Lube by CRC.

Note that in that old post I incorrectly stated that GL-4 was the oil of choice, when I meant GL-5. That's what the ZF manual calls for (for Pantera-era transaxles anyway). CRC makes a GL-5 as well, which is what both I and my wife are running in our respective Panteras.

FWIW, when I had Lloyd rebuild my Pantera-sourced gearbox for the GT40 I don't own yet, I talked him into trading me an old Mangusta tail piece for the Pantera piece. They are nominally identical, but the Mangusta unit has a fill plug as Darryl mentions. It takes all the guesswork out of filling the gearbox--just pour the goo in until it dribbles out, and you're full. He had a few more of them sitting on the shelf at the time (last year), so if you are sending a gearbox to him for GT40 conversion, it doesn't hurt to ask that question....