zf-5 or any transmission with over drive swap

[abronson47]

Hello everyone, I'm a new member here, and I'm sure this question has been asked a million times but I'm having trouble finding information on a zf-5 (or anything of the likes) swap, specifically a parts list and a list of possible modifications that need to be done to fit both the transmission, transfer case, and the drive shaft and whatever else needs to be done. My truck is a 1985 Ford F-250 XLT Lariat 4x4 with the 7.5L engine and T-19 transmission. I've searched youtube to no avail, for the 4x4 at least. I've surfed all sorts of forums and still, not much information to go off of. If this question has already been answered, please direct me to the thread with the answers, maybe save me the time from scrolling through 101 pages of the same question lol.

It seems like these trucks haven't picked up in popularity like the 70's era quite yet due to the lack of information out there for the variety this truck came in during it's time. But that's perfectly fine with me, it's my favorite truck and as long as things stay cheap, I'm happy! I'd just really like to have an Overdrive option for this old girl!

[Gary Lewis]

Welcome! Glad you joined!

But, you probably missed the email you were sent asking you to go to the New Members Start Here folder, read the guidelines, and then introduce yourself in that folder. We ask that because we hold everyone to those guidelines and want you to have had a good chance to see them. And since they are posted there...

So, have you read them?

And now on to the question at hand. My truck, Big Blue, started life as a 1985 Ford F-250 XLT Lariat Explorer 4x4 with the 7.5L engine and T-19 transmission. It is now running Ford's EEC-V EFI system and a ZF5-42 tranny. Yesterday it turned in 12.8 MPG on a 170 mile trip my wife and I took, so it is running well.

The transfer case you have, which should be the BW1345, will bolt up. And I think the driveshafts you have work, but I'm not sure about that as I had to change out the front one because I changed the front axle to a D60. I think I used the original rear driveshaft though.

Obviously you'll need a new clutch as the input shaft on the ZF is a lot bigger. And you'll need the taller transmission cover from later years as the ZF sits higher.

I'm sure someone else will chime in on what I've forgotten, but you've come to the right place - we've done it.

[ArdWrknTrk]

Welcome! Glad you joined!

But, you probably missed the email you were sent asking you to go to the New Members Start Here folder, read the guidelines, and then introduce yourself in that folder. We ask that because we hold everyone to those guidelines and want you to have had a good chance to see them. And since they are posted there...

So, have you read them?

And now on to the question at hand. My truck, Big Blue, started life as a 1985 Ford F-250 XLT Lariat Explorer 4x4 with the 7.5L engine and T-19 transmission. It is now running Ford's EEC-V EFI system and a ZF5-42 tranny. Yesterday it turned in 12.8 MPG on a 170 mile trip my wife and I took, so it is running well.

The transfer case you have, which should be the BW1345, will bolt up. And I think the driveshafts you have work, but I'm not sure about that as I had to change out the front one because I changed the front axle to a D60. I think I used the original rear driveshaft though.

Obviously you'll need a new clutch as the input shaft on the ZF is a lot bigger. And you'll need the taller transmission cover from later years as the ZF sits higher.

I'm sure someone else will chime in on what I've forgotten, but you've come to the right place - we've done it.

I've swapped my T-19 for a Zf-5 as well.

It is the only manual overdrive option with the proper bell housing pattern.

Gary is pretty spot on.

My front driveshaft fit without issue.

The one other thing I can think of is that the transmission cross member needs to be shifted to the rear.

 

[Gary Lewis]

I've swapped my T-19 for a Zf-5 as well.

It is the only manual overdrive option with the proper bell housing pattern.

Gary is pretty spot on.

My front driveshaft fit without issue.

The one other thing I can think of is that the transmission cross member needs to be shifted to the rear.

Jim - I forgot about the crossmember. Yes, it needs to go about 3/4" to the rear.

When I put the ZF in Dad's truck I jacked the cab up and redrilled the frame to take the gussets that far back as well. But on Big Blue I redrilled the bottom of the frame to take the crossmember and used the original holes in the top of the frame for the top of the gussets. It did put the gussets in a bit of a twist, but not too bad and it seems to work fine.

[Littlebeefy]

Jim - I forgot about the crossmember. Yes, it needs to go about 3/4" to the rear.

When I put the ZF in Dad's truck I jacked the cab up and redrilled the frame to take the gussets that far back as well. But on Big Blue I redrilled the bottom of the frame to take the crossmember and used the original holes in the top of the frame for the top of the gussets. It did put the gussets in a bit of a twist, but not too bad and it seems to work fine.

I did the ZF5 swap last year and am very happy with it. I have the granny first gear. Hill starts in 2nd without a problem. 4.56 gearing on final drive with 37s and I am at 2000 RPM at 70 mph.

The transmission crossmember (and gussets!) can be reused if you drill the frame which can be a pain. You may just want to find a crossmember and gussets from a donor truck. The ZF5 tailhousing has different lengths (between the S5-42 and S5-47) so I'd get the transmission before hunting the crossmember. You will also need the transmission mount. Match whatever is on your engine mounts either poly or rubber.

The clutch comes in different sizes. Centerforce makes the biggest one IIRC. You will need the pilot bearing, throw out bearing, clutch fork, clutch slave and master (get a prebled unit IMHO as the system is a pain to bleed). If you had a manual already, your electrical harness and existing pedals will work fine.

The ZF5 is BIG. I don't know if the controls for that transfer case will work with the ZF5 in there. I'm not sure if you have to have linkage specific to the transmission. Maybe someone can chime in.

I did the short throw conversion with Midwest Transmission and am very happy with the results. Also, JB Fabrication makes a nice looking shift stick and boot.

 

[Littlebeefy]

I did the ZF5 swap last year and am very happy with it. I have the granny first gear. Hill starts in 2nd without a problem. 4.56 gearing on final drive with 37s and I am at 2000 RPM at 70 mph.

The transmission crossmember (and gussets!) can be reused if you drill the frame which can be a pain. You may just want to find a crossmember and gussets from a donor truck. The ZF5 tailhousing has different lengths (between the S5-42 and S5-47) so I'd get the transmission before hunting the crossmember. You will also need the transmission mount. Match whatever is on your engine mounts either poly or rubber.

The clutch comes in different sizes. Centerforce makes the biggest one IIRC. You will need the pilot bearing, throw out bearing, clutch fork, clutch slave and master (get a prebled unit IMHO as the system is a pain to bleed). If you had a manual already, your electrical harness and existing pedals will work fine.

The ZF5 is BIG. I don't know if the controls for that transfer case will work with the ZF5 in there. I'm not sure if you have to have linkage specific to the transmission. Maybe someone can chime in.

I did the short throw conversion with Midwest Transmission and am very happy with the results. Also, JB Fabrication makes a nice looking shift stick and boot.

I just reread your post and I realized you have an 85, not a 95. Your existing transfer case controls WILL NOT WORK. When the ZF5 was available from the factory, the controls had already been relocated from the transmission tunnel cover to the floor-board in front of it and just behind the gas pedal. You will need to cut a hole to accommodate the controls or go with a cable actuated system.

Frankly, this is probably the most difficult part of the whole project (other than finding a good ZF5 hahaha).

[ArdWrknTrk]

I just reread your post and I realized you have an 85, not a 95. Your existing transfer case controls WILL NOT WORK. When the ZF5 was available from the factory, the controls had already been relocated from the transmission tunnel cover to the floor-board in front of it and just behind the gas pedal. You will need to cut a hole to accommodate the controls or go with a cable actuated system.

Frankly, this is probably the most difficult part of the whole project (other than finding a good ZF5 hahaha).

I've managed to move my '87 1356 transfer case linkage over to the '91 Zf-5 in my truck.

I think it's very fortunate that I didn't have to find that funky shift boot and cut a hole in the side of my tunnel.

If it stops raining I may go out and try to snap a pic.

[Gary Lewis]

I've managed to move my '87 1356 transfer case linkage over to the '91 Zf-5 in my truck.

I think it's very fortunate that I didn't have to find that funky shift boot and cut a hole in the side of my tunnel.

If it stops raining I may go out and try to snap a pic.

I used the same BW1354 and controls that Big Blue came with behind the ZF5.

[Gary Lewis]

I just reread your post and I realized you have an 85, not a 95. Your existing transfer case controls WILL NOT WORK. When the ZF5 was available from the factory, the controls had already been relocated from the transmission tunnel cover to the floor-board in front of it and just behind the gas pedal. You will need to cut a hole to accommodate the controls or go with a cable actuated system.

Frankly, this is probably the most difficult part of the whole project (other than finding a good ZF5 hahaha).

Chad - Tell us more about what t-case you used? Is that the NP205? I've not played with one of those, but what made it difficult to use the linkage with it?

[ArdWrknTrk]

I did the ZF5 swap last year and am very happy with it. I have the granny first gear. Hill starts in 2nd without a problem. 4.56 gearing on final drive with 37s and I am at 2000 RPM at 70 mph.

The transmission crossmember (and gussets!) can be reused if you drill the frame which can be a pain. You may just want to find a crossmember and gussets from a donor truck. The ZF5 tailhousing has different lengths (between the S5-42 and S5-47) so I'd get the transmission before hunting the crossmember. You will also need the transmission mount. Match whatever is on your engine mounts either poly or rubber.

The clutch comes in different sizes. Centerforce makes the biggest one IIRC. You will need the pilot bearing, throw out bearing, clutch fork, clutch slave and master (get a prebled unit IMHO as the system is a pain to bleed). If you had a manual already, your electrical harness and existing pedals will work fine.

The ZF5 is BIG. I don't know if the controls for that transfer case will work with the ZF5 in there. I'm not sure if you have to have linkage specific to the transmission. Maybe someone can chime in.

I did the short throw conversion with Midwest Transmission and am very happy with the results. Also, JB Fabrication makes a nice looking shift stick and boot.

My existing clutch fork and slave worked just fine.

I'm not sure why you had all these fitment problems Chad.

What engine and gearbox were in your Bronco when you swapped in your Zf-5? 🤔