FM145 - bad input shaft bearing

[palouse]

I’ve kind of been going in circles searching and reading about this trying to figure out how to approach it. I figured it may just be best to post here and get some input.

My daughter’s 85 Ranger (2.3, 4x4, standard cab, long bed) has an FM145 with a bad input shaft bearing; it squeals in every gear except 4th.

I tried contacting a few transmission shops about replacing the bearing and it seems like something they don’t want to touch. Then I looked into getting a rebuilt transmission, and the FM145s aren’t the most common. After that, I read some posts on here (mostly by adsm08) about swapping for a M50D, which seems like possibly the most ideal option in the long run.

I’m hoping some of you more experienced with this could give me your input on what you may do in this situation and help point me in the right direction. I’d like to keep the truck for a while, or indefinitely, it’s in great shape and has 83k original miles on it. These are what I think my options are, could you tell me what you would do?

1. Continue to look for a shop that will replace just the bad input shaft bearing.
2. Look for a shop that will rebuild the entire transmission.
3. Get a rebuilt FM145.
4. Swap in a M50D.
5. Other options?

I guess I should mention as a caveat, I’d prefer to have this done at a shop, or mostly at a shop. I’m sure I could tackle this if I had plenty of time and extra space, but I’m lacking in both of those right now.

Thanks in advance.

 

[Shran]

Personally I would find someone to go through it and just rebuild what you have. They are not hard to rebuild nor are they costly. I redid the one in my wife's truck and an FM-146 for my '85 and had no more than $300 into each and that included all near bearings, syncros, input shaft on one, a couple of gears on the other, and the 5th gear revised bearing. You do need a couple of somewhat specialty tools though.

There are a lot of FM transmission haters on here but how long has this one of yours lasted? Mine have a ton of miles on them. They are just fine behind low power engines and they shift really nice compared to the M5OD. There are so many changes required to swap yours to an M5OD that I don't feel it would be worthwhile unless you have access to really good junkyards, a fair bit of time and some money. Even then you may be money ahead to just rebuild yours.

If you had a FM-146 or A4LD auto - same length as a M5OD - then I would be more in favor of the swap.

I would check with a truck shop - as opposed to a transmission shop - like a place that works on big rigs. Usually they are much more likely to be comfortable with manual transmissions. Inland Truck Parts out here will do them. Anywhere that does axle gearing might be a good place to try as well. I have found that most "transmission" shops will only do automatics these days. That is why I started rebuilding my own and found that for the most part, they are not hard to work on.

 

[palouse]

I appreciate the advice. You're right, most of the info I was coming across related to people saying the FM wasn't worth the trouble. I'm glad to hear your perspective. I don't have any plans to put anything larger than its current engine in it. We have a lot of tractor shops around here that don't advertise as mechanics, but will do work if you call. Most of their work is on the wheat farmer's combines and grain hauling trucks. I bet one of them can help or at least point me in the right direction.

Cheers and thanks again.

 

[gearfather]

pm sent

 

[gearfather]

Personally I would find someone to go through it and just rebuild what you have. They are not hard to rebuild nor are they costly. I redid the one in my wife's truck and an FM-146 for my '85 and had no more than $300 into each and that included all near bearings, syncros, input shaft on one, a couple of gears on the other, and the 5th gear revised bearing. You do need a couple of somewhat specialty tools though.

There are a lot of FM transmission haters on here but how long has this one of yours lasted? Mine have a ton of miles on them. They are just fine behind low power engines and they shift really nice compared to the M5OD. There are so many changes required to swap yours to an M5OD that I don't feel it would be worthwhile unless you have access to really good junkyards, a fair bit of time and some money. Even then you may be money ahead to just rebuild yours.

If you had a FM-146 or A4LD auto - same length as a M5OD - then I would be more in favor of the swap.

I would check with a truck shop - as opposed to a transmission shop - like a place that works on big rigs. Usually they are much more likely to be comfortable with manual transmissions. Inland Truck Parts out here will do them. Anywhere that does axle gearing might be a good place to try as well. I have found that most "transmission" shops will only do automatics these days. That is why I started rebuilding my own and found that for the most part, they are not hard to work on.

The fm145 was not a bad trans.. the 2 biggest problems were people putting 80-90 in them and splitting 5th gear on the mainshaft by driving 25mph in 5th thinking they will get 40 mpg...

 

[Shran]

Here are a couple videos of rebuilding one of these if you want a vague idea of what you would be getting into if you try it yourself:

 

[palouse]

Here are a couple videos of rebuilding one of these if you want a vague idea of what you would be getting into if you try it yourself:

"It's easier to get into Fort Knox"

Oh boy. I'm going to watch these this evening. Thanks for sending!

 

[palouse]

So, I just checked the transmission fluid level and there's ATF in there...

I'm not sure if this is hijacking my own thread, or if it should go in a different post, but since it is still part of the same rabbit hole, I figured I'd continue it on this thread.

My Haynes manual says this transmission takes SAE 80W, this post and this post lead me to believe that ATF is a very bad thing to have in a FM145. I pulled the plug on the drivers side and sure enough, the fluid is red.

So is flushing the ATF out something I can do by draining, filling, draining again? Or using something like Seafoam Trans Tune? Or is it even possible to flush out the ATF?

 

[tw205]

Did you ID the trans by the door tag or by visually ID? Your correct it should be gear lube in an FM 145/146. M50D takes Mercon atf. Could be PO put incorrect fluid in it. Does your clutch line connect on top of the bell housing or on the side? 145 will be on top.

 

[palouse]

Did you ID the trans by the door tag or by visually ID?

By the door tag. I've got it parked at my neighbor's right now because roofers are using my driveway. I'll run over there to do a visual ID to verify.

 

[palouse]

Does your clutch line connect on top of the bell housing or on the side? 145 will be on top.

It connects toward the top, might not be centered on the top, but it's on the top portion. Also, there is a bolted metal pan on the bottom and a seam between the bellhousing and case. So, FM145?

 

[tw205]

It connects toward the top, might not be centered on the top, but it's on the top portion. Also, there is a bolted metal pan on the bottom and a seam between the bellhousing and case. So, FM145?

Sounds right. M5OD is one piece. Definitely drain it. Fresh gear lube.

 

[gearfather]

Do not run gear lube if you are going to run it in the winter. run GM Synchromesh..#12345349 regular 80w gear lube can not get in to the needle bearings and it will like **** until it warms up...

 

[gearfather]

pm sent

 

[Shran]

gearfather knows his stuff. What he says is totally correct. Don’t run gear lube in it or ATF.