FM145 strength and how much power it can take

[Zapper]

So I have a 1986 2.3 with the fm145 transmission and I'm going to be building the 2.3, so what should I do to keep it from grenading, since I already know that the synchros are gone, and I have a short throw shifter on it so I shift it harder than normal, so what are some things that I should avoid doing?

 

[Snoranger]

So I have a 1986 2.3 with the fm145 transmission so what are some things that I should avoid doing?

Using the FM145.

 

[Zapper]

Using the FM145.

Well its the factory transmission, and I don't want to put a bunch of money into a transmission that would cost more than the truck itself.

 

[4x4junkie]

Is this a truck you like and want to keep? Or something you just need to get running to sell it?

If the former, why does it matter what the transmission is worth relative to the truck?? If you like the truck, put something good in there.

If the latter, then keep the FM145... Baby it in the meantime, and don't worry about it after it's sold.

FWIW, the FM-series transmissions seem able to tolerate short-medium bursts of power well... It's sustained loading that they seem to have issues with (such as towing a trailer in any gear but 4th uphill at full throttle). The input & output ball bearings tend to get starved of oil and of course they don't like that.

 

[Paulos]

This is the only thing I have found to strengthen the FM145, aside from the updated 5th gear bearing.

Tuff Pan for Ford Ranger FM145 transmission | eBay

Find many great new & used options and get the best deals for Tuff Pan for Ford Ranger FM145 transmission at the best online prices at eBay! Free shipping for many products!

www.ebay.com

They don't appear to make them for the "FM" anymore (only the "KM"), so that eBay auction is the only one I've seen available. Maybe the manufacturer would be willing to make one. I'd probably get one if they were still available.

www.tuffpans.com

Transmission Strengthening Pan kits for Mitsubishi

www.ns-micro.com

 

[adsm08]

Well its the factory transmission, and I don't want to put a bunch of money into a transmission that would cost more than the truck itself.

So by that logic I should have junked the perfectly good running Mustang I have when the $70 throw out bearing grenaded because that part cost more than I paid for the whole car.

The notion that a single part costing more than you paid for the whole vehicle being the point of not fixing it is frankly nothing short of stupid. Don't look at the cost of the repair vs the cost of the vehicle, look at the cost of the repair vs the cost of a similar vehicle that doesn't need that repair.

The input & output ball bearings tend to get starved of oil and of course they don't like that.

To be fair, the fact that they used ball bearings rather than roller bearings is a pretty big issue in and of itself.

 

[rusty ol ranger]

I paid 375 bucks for rusty #2.

Ive pry got, i dont know, north of 1000 into it.

The value of a vehicle cant be priced in dollars if you care about it.

That being said, to answer you question, if it were me id try to find a M5OD from a later lima. Even the TK5 seems (from what ive read over the years) to hold up better then the FM145.

Whats involved in the swamp to a M5OD, i dont know, but its been done around here alot and would probably not be to awful pricy.

 

[adsm08]

Whats involved in the swamp to a M5OD, i dont know, but its been done around here alot and would probably not be to awful pricy.

To swap from an FM145 to an M5OD you need a transmission, a clutch slave and hydraulic line (at this point it is wise to replace the master too) and at least one drive shaft.

The install is fairly straight forward. It bolts up just like the 145 does, the shifter sits a little farther forward, but not enough that a Dremel and a piece of sheet stock can't fix it. The trans crossmember ear rivets have to be cut off and the ears moved back to the rear set of holes. After that it is mostly a bolt-in affair. You need a different drive shaft (or shafts on a 4x4) because it is longer than the 145.

It also uses the quick connect fitting with check valve pointing out the driver's side to connect the line, where the FM145 used an off-center upward facing connection sealed with an o-ring and a butterfly pin near the 11:00 position, so the fitting type, line length, and position are all wrong, which is why they have to be changed. The master cylinder itself is the same, but like I said, with all other components being new it would be wise to replace the master as well.

 

[rusty ol ranger]

@Zapper there ya go.

 

[gw33gp]

Is the FM 145 that much different than the FM146 other than the FM 146 is for the 2.9L? I ran my 89 STX with the FM146 near 200K miles with no problems. I learned not to tow with it in 5th gear but other than that it did very well for me. I towed my race car all over the country and did a considerable amount off road travel with it. I was also not easy on it as my daily driver. Of course I didn't abuse it either. I always ran synthetic gear oil in it and maybe that helped.

I always quick shifted it and it took in in stride. I tried the same thing with the M50D transmission in my 02 Ranger and it did not like it. I learned to shift slower with it, but it has been a good transmission for me too. I never understood why the Mitsubishi transmission got such a bad rap. Apparently, many others didn't have the luck I did with it.

 

[Snoranger]

Is the FM 145 that much different than the FM146 other than the FM 146 is for the 2.9L? I ran my 89 STX with the FM146 near 200K miles with no problems. I learned not to tow with it in 5th gear but other than that it did very well for me. I towed my race car all over the country and did a considerable amount off road travel with it. I was also not easy on it as my daily driver. Of course I didn't abuse it either. I always ran synthetic gear oil in it and maybe that helped.

I always quick shifted it and it took in in stride. I tried the same thing with the MD-50 transmission in my 02 Ranger and it did not like it. I learned to shift slower with it, but it has been a good transmission for me too. I never understood why the Mitsubishi transmission got such a bad rap. Apparently, many others didn't have the luck I did with it.

I destroyed 4 fm146s in under 2 years behind a 2.9l. The M5 I swapped in lasted 5 years in that truck, and a few more in my Explorer.

 

[adsm08]

Is the FM 145 that much different than the FM146 other than the FM 146 is for the 2.9L?

The FM145 and 146 were both used with the 2.9. The 146 was longer, being the same length as the A4LD and M5OD, the 145 was two inches shorter. Both used gear oil rather than ATF, and had the same basic construction for the shifter bushings, but the 146 used a straight stick like the M5OD, the 145 was crooked in the middle similar to the Hurst shifter for the M5OD. The 146 solved the 5th gear issues the 145 had, but retained the weak ball bearings used for the input and output shaft mains.

The 146 used the same clutch line hookup as the M5ODs, likely done because they ran side by side for a few years, so Ford only needed one line assembly.

FWIW the 146 that came in my B2 seemed to shift much smoother than the 145 my Ranger came with.

 

[gw33gp]

adsm, thank you for the detailed information. It sounds like the weaker input and output bearings in the FM-145 and FM-146 is the main reason it has a bad reputation. Apparently, I did something right to not loose those bearings. If the FM145 had a 5th gear worse than the FM-146, it truly is a weak transmission.

 

[Shran]

Both the '145 and '146 would be fine behind a 4 cylinder unless you're dropping a turbo or something on it. As far as what you can do with it to make it better: a rebuild with quality bearings would be item #1 on the list, make sure the shift forks and stuff don't have any wear on them, and just be nice to it. There are still a lot of them on the road, they're not real strong but they'll last a good while if you're not abusive.

Side note, I have personally seen more grenaded M5ODs than any other manual trans... in fact I have three of them in my parts stash right now. One broken input shaft, one with teeth sheared off two gears, and another that gets stuck in gear, plus one I rebuilt that had eaten the 5th/reverse cluster. I parted out a lot of 1st gens years ago and never saw carnage like that... a lot of them were simply worn out as expected after a million miles but very few with broken internal parts.

 

[rusty ol ranger]

To be fair though, the M5OD suffered from massive leakage issues at the rail plugs, theres many more of them out there, and were used behind bigger engines in heavier trucks.

Not defending them, i cant stand them with their worthless reverse gear, but just saying...