ZF5 Gearing Question

[88 F-350 4X4]

Hello guys...
Maybe this has been covered before however i was not able to find an answer.
Is it possible to install the lower first gear from a gas zf into a diesel zf?
I have 3.55 gears in my truck and sometimes when towing a heavy load i have a hard time getting going.
Feel like my clutch would thank me if i had a lower first to get things moving.
Thanks very much,

 

[hesutton]

I've never tried swapping gears in the ZF5, but you could do it. Big job for most of us shade tree guys.

I did "typ4" mods to a 460 ZF5 and have it behind the 6.9 in my crew cab. The lower first and reverse are nice. The OD is slightly taller as well.
My only complaint is the gap between 3rd and 4th. When hauling, you need to give 3rd some more RPM than you'd expect before shifting into 4th.

Empty, I rarely use 1st. I treat the ZF like a 3 speed while driving in town. Start in 2nd, and 3rd and 4th give me all the range I need. When hauling, 1st is wonderful.

I used a drill press with a four fluted end mill to machine the diesel bolt pattern into the 460 bell housing. The diesel trans adaptor plate was the template.

Heath

 

[hesutton]

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[icanfixall]

Heath I remember very well how you used your ingenuity to drill the holes needed with that adapter as a template. Also using the 4 fluted end was was really a great idea. It has 4 cutters and it works best on any blind hole or mismatched hole. Overall it was a genious idea how you solved this issue.

 

[jibronee]

What about swapping trans for a wide ratio diesel trans?

 

[compressionignitionrules]

you can change all the internals from a bigblock ZF into your diesel, but if you are trying to change just 1st gear, you need to change the countershaft to match the 1st gear and when you do that, none of your other gears will match up from mainshaft to countershaft.

basically you must change ALL the internals into your diesel case.

 

[Shadetreemechanic]

Easiest thing for you would be to swap transmissions. In an 89 you have a zf-42 early model five speed. I think it was 95 that they switch to the zf-47. That transmission, though it looks identical had several upgrades, one of which was a lower first gear.
I think you can also put the first out of a zf-47 in a zf-42, though I have not tried it, only read about it on the internet.

 

[jibronee]

I have both, wide and close ratio, zf42's. Fourth and fifth gear is the same.

http://www.dieselhub.com/trans/zf-5-speed.html

See link

 

[shawn deere]

Could start in 4 low, get to a favorable spot to start over in 2 high

 

[shawn deere]

Either lock the hubs in or keep in mind the torque on the drive shaft going back

I use 4 low all the time backing up too
And mud
And pickles

 

[79jasper]

Either lock the hubs in or keep in mind the torque on the drive shaft going back

I use 4 low all the time backing up too
And mud
And pickles

Me too.
Or if I'm going through a parking lot and want people to think I have 39 gears. Lol

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[88 F-350 4X4]

Cool. Thanks for all the replies guys.