Zf5 from a 460 truck

[ROCK HARVEY]

I bought a non-running truck (89 f-250 4x4 5 speed) exactly 2 months ago, and have been going through the process of getting it fixed up. I got the engine running, but have only driven it a couple times for short distances. The transmission seemed loud to me, but it has a solid flywheel conversion so I assumed it was just rollover noise. When I drained the transmission I noticed the fluid smelled burnt, wasn’t ATF, and there were a couple tiny bits of metal on the plug. Now I’m thinking the noise was more sinister. I found a low-mileage zf5-42 4x4 locally, but it’s from a 460 gas truck. I’ve heard that you can re-drill the top two bolts to make it mount to the IDI, but has anyone here actually done it? I noticed this on Diesel Conversion Specialists’ website:

“The best way to identify if you have a gasoline version of the ZF5 is the .5" dowels on the bellhousing. The dowel pins are also staggered, the driver's side being higher up on the bellhousing than the passenger side. The diesel version uses .375" dowel and are directly across from one another.”

I do understand that the gasser zf5s are geared slightly differently. I’ve also looked into rebuilding my zf5, and it looks time consuming but not too difficultt. The way I see it I have 3 options: rebuild my current tranny, attempt swap to gasser tranny, or swap cases between the two transmissions. What do you guys recommend?

 

[lotzagoodstuff]

I would fill the current ZF up with the correct aft fluid and drive it around evaluating the performance. If it seems better, I’d plan to switch to this Redline MTL fluid based on this thread:


https://www.oilburners.net/threads/zf5-rebuild-preferences-diy-rebuilder-etc.90533/

 

[IDIBRONCO]

I agree with lotzagoodstuff. That's how I would start. A couple of pieces of metal on your drain plug magnet don't necessarily mean impending transmission death. If I had to guess, I would say that what you drained out of your transmission was probably 80w/90 or some other type of gear lube. It happens, although it doesn't seems to happen as often as it did 20 years ago.
Yes people have redrilled their transmission bellhousings successfully. I believe that it's more involved than just two new holes. I believe that it's actually four holes that need to be worked on. The good news is that, if you end up having to go this route, you have the pattern for doing this already on your truck. The bad (sort of) news is that it's your adapter plate and you'll have to remove the transmission to be able to use it unless you have another one sitting around to use. Don't worry about the starter mounting holes in the gasoline bellhousing. Our IDI starters bolt onto the adapter plate.

 

[ROCK HARVEY]

Yeah I do think the stuff I drained out was gear oil. I went ahead and filled it with synthetic mercon V, but I’m intrigued by that Redline MTL product. I’ll try to pay close attention to the noises once I get it back on the road (rusted brake lines have it parked right now) to see if I think the bearings are shot or if it’s just gear rollover. I also went ahead and bought the gasser zf5. They are not easy to find around here, so I figured I’d pull the trigger on this one even if I don’t need it for a while. If/when I do drop the transmission, I’ll make a thread comparing the gasser and diesel bellhousings in detail. In the meantime I’ll try to do some research to see what all I’d have to do to mount this gasser trans to my truck. I’d like to swap it in, then attempt a rebuild of my original trans. If anybody has installed a 460 zf5 behind their IDI I’d love to hear the details.

 

[lotzagoodstuff]

will a 460 zf bolt to a 7.3??

i was wondering if a 460 zf bolts to a 7.3.. my buddy has a 7.3/e4od truck and wants to swap to a zf, i have a spare 460 trans and the pattern looks the same but we cant find any info on it.. thanks

www.oilburners.net

 

[ROCK HARVEY]

I should have known there would be a tech article on re-drilling a 460 zf5. I guess there’s no need for me to do the photo comparison. It looks like more drilling than I had previously thought, but I’ll definitely give it a try if my current tranny is cooked.

 

[Mulochico]

From what I've heard one of the advantages of the gasser trans is a lower reverse. That would be a big plus for me if I had the opportunity to do the swap.

 

[ROCK HARVEY]

Yeah 5.24:1 is a pretty big change from 3.79:1!

 

[u2slow]

In a 4wd you always have low range. The rest of the time you have as many 'driving' gears as the 6 speed guys.

In a hard-use 2wd I see the benefit of deeper 1st and R.

My preference would be to figure out that diesel ZF, even if it takes a rebuild kit with synchros. Failing that, I'd try the 460 one.

 

[ifrythings]

I had a 460 zf5 behind my engine and absolutely hated it, first was useless, 2nd was a bit tall to start off in and having to rev it up to 2500 rpm so you didn’t lug it in the next gear sucked, if I shifted at 2k it would be around 1K in the next gear. I only dd but if I towed it would be even worse. I’d stick with the diesel close ratio.

 

[ROCK HARVEY]

I had a 460 zf5 behind my engine and absolutely hated it, first was useless, 2nd was a bit tall to start off in and having to rev it up to 2500 rpm so you didn’t lug it in the next gear sucked, if I shifted at 2k it would be around 1K in the next gear. I only dd but if I towed it would be even worse. I’d stick with the diesel close ratio.

That’s good info, Thanks. I might have pulled the trigger too soon on this 460 zf5, but I can always re-sell it. Hopefully I can get the brake lines done this weekend so I can start driving the truck and determine how far gone the current trans is.

 

[ROCK HARVEY]

Interesting side note: the gasser trans was made in USA and the diesel trans was made in Germany. I doubt there’s a difference in quality, but I thought it was interesting.