Re: ZF fluid change time!
 

Yes, it was. The posted speed limit is 75 so you can get a bit of a running start so the jump up from 75-115 is easy (frankly TOO easy) in the Z.

Thanks for the offer- Hopefully I wont need to PM you!

Re: ZF fluid change time!
 

Many times on the road to Dallas, & Ok City, in sleepers w/UPS. Only thing was our tractors were maxed out @70mph unless we were going down hill....lol I can only imagine what it would be like to run at an extended time in the Z at those (115) speeds. Around here it would only be for a few seconds if that on a deserted road and in the middle of the night.....

Good luck on the fluid change......

Re: ZF fluid change time!
 

I did mine by myself and on jack stands. 17mm hex which is not hard to find. Like they said - remove fill plug first. I used the funnel and garden hose method to fill it back up. Really wasn't a bad job and yes the trans shifted much better after...

Re: ZF fluid change time!
 

I took it to my local oil change place that I'm comfortable with. They have a young mechanic that lets me get under the car with him.

The trans fluid looked like maple syrup and I have a feeling that it is original (the car has 70k on it) and never been changed. We load it with AMSOIL Synchromesh and put a new plug (with teflon tape) on the drain. Thanks for the tip on the new plug because it was needed!

While up in the air, we did an oil change with Mobile 1 5w30 synthetic-- it was due in 300 miles anyway.

The shifting was noticeably smoother on the short drive home, so I'm a beliver!

Thanks for the hints!

Re: ZF fluid change time!
 

NOT wanting to get into a discussion about crankcase oil and flat tappets...but after experiencing first hand what can happen, ya might want to read the article on the subject on Marc Haibeck's web site. (Hint: ZDDP)

Re: ZF fluid change time!
 

Yeah, but you lit the fuse...

So, I filled with Mobile1 5W30 about 10 miles ago. The previous owner handed me the car with fresh Pennsoil 5W30 Syn. The car runs great, has 70k on a non modified engine (sans Haibeck chip) and I drive reasonanbly sane. (Okay, it is a LT5, so it sees 7k a coupel of times a month).

I know Marc recommends AMSOIL but says the Mobile1 is "acceptable."

So, how vulnerable is my engine..... REALLY?

Re: ZF fluid change time!
 

I blended a couple quarts of the z-rod Amsoil with the jug of mobil1 from walmart. The z-rod is a little concentrated on the zddp additive-way more than ohc tappets need. You can duplicate 1990's mobil1 additive specs by using 2-3 qts of the zrod and the rest modern mobil1.

so then a 12 qt box of the Amsoil will last 4-6 oil changes. You get increased protection, but without overdoing it so much that it costs too much or fouls the catalysts.

Re: ZF fluid change time!
 

Somewhere on here I read that Mobil 1 High Mileage formula has a lot of ZDDP in it I believe. That's what I use in ALL my vehicles. Perhaps someone like Dynomite knows where that article is and can chime in...
That said - you won't hurt your engine with what you put in it just this once. When you change it again - then use some better recommended stuff with more ZDDP...

Re: ZF fluid change time!
 

I also use Mobil 1 High Mileage 10W-40, which has a decent amount of
Phosphorus and Zinc. 1000 ppm & 1100 ppm

This may be the article you are referring to, from Marc's website.

http://zr1specialist.com/HAT%20Web/a...5%20Engine.pdf

Re: ZF fluid change time!
 

I find this helpful.
Hope you do as well

https://mobiloil.com/~/media/amer/us...ecs-guide.ashx

Thanks
Marty