Could someone please advise me? I am considering converting my manual transmission '99 F350 4x4 dually into an automatic. I have a 6 speed ZF in it currently that recently lost 3rd gear and 4th slips out when decelerating, so it seems that the trany does not have long to live. I have a functional 4R100 in a truck that has a blown engine that I could swap in. Is this exchange advisable/doable (I've heard bad things about the durability of the 4R100). I am trying to save some money and I am leery about purchasing a used or rebuilt ZF because of the cost and/or lack of a guarantee. Are there linkage/computer issues I should be aware of. I was thinking I could just cover the Shifter hole and install a floor mount shifter like the B&M in its place. I am interested in any advice that people are willing to share.

If this has been discussed elsewhere I could not find it, so please give a hint about search phrases to use to find it.

 

You normally don't hear of a ZF getting munched. Those are pretty stout units.

You'll need to install a computer that controls a 4R100 or install a stand alone transmission controller to make this work. You'll also need the requisite wiring, and the steering column out of the wrecked truck to give you a shifter.

In addition, you'll need a way to cool the transmission. If the wrecked truck has a good radiator and transmission lines you're in luck.

Overall, it sounds like a real PITA.

 

If your worried about a 4R100 lasting, after you've already broke arguably the strongest 6 speed in the light duty truck segment, you have reason to be so.

I would get another ZF 6spd and put in it. I think it was a fluke, or a defect in the trans that developed into a major problem over time. You will be WAY bettter off with the 6spd, and spend less money to replace it if it breaks again.

The 4R100 is a good trans, but has it's weak points. They are very expensive to R&R, and a good rebuilt unit can run you 2k before labor. BTS and John wood Trans are cream of the crop, and have a price tag to match. Supposedly, BTS trans are truly bulletproof.

Your conversion to an Automatic would prove expensive and time consuming. Lots of stuff has to change in order to use the auto. It would be a wiring nightmare, as the trans is electonically controlled. Many wiring harnesses have to be replaced or added, not to mention the work to take out your clutch pedal, plug the holes in the firewall, change the flywheel, get a flexplate, and torque converter ( in which there is no way to test if you have a good or not from a junk yard)

IMHO, just get another 6spd......

 

I would vote for another 6 speed.

 

Thanks for the great advice. I was not eager to put the auto in but it is a transmission that I do have, and the list of other changes/parts I would have to scavenge from the other truck would disable its' potential also.

So, any thoughts on weather I can trust a junkyard ZF or should I have mine worked on/rebuilt. If you think I should just have it worked on does anyone have a recommendation as to who does good transmission work in Colorado?

 

Fishing:

Manual transmissions and work crews can be a bad combination, work crews in general tend to be hard on equipment. I am sure that if it had been me or someone who gave a s**t and had even a little bit of finesse driving, the thing would not have been ruined at only 120K miles.

Thanks again for the advice on the swap, I guess I'll have to just save my nickels till i can afford another ZF. I would appreciate thoughts on a used salvage ZF re. good/bad idea.

 

I have always gotten junk yard parts and been happy with them.
Just make sure its not too loose and it goes into all the gears ok.

You may know this, but it has to come from a Power stroke 4x4.

 

Work crews are hard on stuff. Some guys that I know actually get a stippend to get a truck on their own from their construction company, so that they are responsible for the maintence and repairs. That makes them WAY more accountable when its their ride to and from work.

It seems odd to me that it would be 3rd and 4th that you lost and not L 1st or 2nd. IMO, seems like they would have to be trying to break it, to actually affect gears that usually are the least used or at least not driven in for the most drive time out of all 6 gears.

I think a used ZF would be fine, Find a wreck, check the slop, and engagement in every gear, and go for it. If it a diesel truck, the donor has to be a diesel too. and the same for a gas truck.

 

Its a 7.3 PSD. He said its a 99 6 speed and in 99 the gassers could only be gotten with a 5 speed.

I agree about the abuse. Sounds like somebody was slip shifting and has no clue how to.

 

The truck has really low final drive gearing so starting out in 1st or 2nd is no problem and therefore 3rd is the gear that gets used a lot, especially in stop and go traffic. I went on line and found a few ZF 6 speeds in other states. I was considering just having one hand picked by the people at the salvage yard and having them ship it, but I was having trust issues and decided to ask you guys. After hearing your advice I will probably just keep my eyes open for one closer to home or get some assurances before I drive to pick it up and check it out for my self either way.

Thanks again for the advice and wish me luck.

 

If you do decide to swap to an automatic let me know, I'll buy all of your old transmission stuff. My 4R100 just failed for the 2nd time.

 

I'd sell the auto from the other truck and rebuild or replace your 6 speed.