Horrid noise in 5th on an M5OD, thoughts on my parts list?

[scotts90ranger]

Drove the '90 to work today and it'd been a while since it's been on the highway, I do remember it being somewhat noisy in 5th for a while but not that bad... sounds like gear backlash or something when under load, silent in the rest of the gears (didn't go into reverse yet today so not sure there...). Any likely cause of the noise? Just worn out? It wouldn't be something dumb like the big nut on the output shaft backing off would it?

This transmission has somewhere north of 200k on it, we rebuilt it (bearings and synchros and one slider that had wear) when I did the lift around 11 years ago but it only has 20k miles or so on it...

The transmission is a '89, I know there were some changes over the years like one of the sliders having more or less teeth in I wanna say '92, but if I were to pick up a spare transmission, any years better than others? I don't remember... Going to try to pick up a 2.3L 4x2 trans because they were most common, swapping to my 4x4 stuff doesn't scare me, I kinda remember getting in there, don't remember it being all that bad...

Edit: The noise is kinda a rattle, with no carpet or insulation on the floor it really resonates through the cab... doesn't sound chunky like a gear, more like something is loose and has play... kinda like idle in low range first gear rattling with all the gear lash stacked up except for it's happening at almost 4000rpm output shaft speed...

 

[scotts90ranger]

Just got home, the noise is there in 3rd at least, the engine is too noisy in second to notice it but it's much quieter in third than 5th... I'm pretty sure I should just get a core trans and make a good one...

 

[scotts90ranger]

There's a 190k '98 2.5L with M5OD on craigslist a couple hours away for $450, I imagine that has the different shift tower (pins forward and backward instead of side to side like my '90) and other things, but my tail shaft and housing should go right in, right? What about going to the older style slave cylinder that I would need for the '90's system, would it go on?

 

[scotts90ranger]

I found a whole '92 fairly local for parts missing a few things (driveshaft, radiator, alternator and starter from the ad...) but it's a manual trans with 2.3L for $400 so that would be more good parts for me...

 

[Shran]

Hard to pin down a noise like that without opening it up but have you ruled out your t-case shifter (assuming you have one?) Two of my trucks will make obnoxious rattling noises at certain RPMs and in certain gears...it's the t-case shifter, if I pull it just a tiny bit to the left while driving it'll quit making that noise. Sometimes I will shove a glove between that and the trans shifter when I'm on road trips to keep the noise down.

 

[scotts90ranger]

Yeah, I know, didn't know if noise in 3rd and 5th narrowed much down (I haven't tried going 4k rpm in reverse to see if it's noisy to narrow it down to a rear bearing... ), thinking about it more to me it probably means the rear bearing on the counter shaft or the rear bearing on the output shaft... I got one of the cheap trans rebuild kits back in the day from Ebay most likely...

I'd like it to be fixed by mid March so I'm going to try to come up with a core trans, the person with the '92 hasn't emailed me back yet so not too hopeful but we'll see, if I did end up with the '98 trans would the older style slave bolt up as long as I get the right shifter for the top? Older output shaft and tail housing bolt on fine? The only thing I really question is the slave cylinder...

 

[scotts90ranger]

The guy with the '92 got back to me, so we'll see tomorrow hopefully

 

[scotts90ranger]

Ok, now that I have a parts rig with a lower mile drivetrain supposedly I'm going to try to fix what I have , I've been running the same clutch for going on 12 years and probably at least 50k miles of turbo ranger shenanigan's, haven't really had any problems with it slipping but while there ya know... So, thoughts on this parts list?

-LUK master and slave cylinders, even with shipping Rock Auto is cheaper than elsewhere so probably do that
-new Centerforce friction disc, undecided on a new pressure plate for $150 more... doubt the pressure plate I have is too worn
-REBUILD KIT

So, any better options than Luk for master and slave? The slave is shot anyway so might as well replace both... saw a Perfection Clutch bled kit but changing the slave is a pain so not looking to experiment too much...

Of course I plan on doing the rear main while there, I changed the pilot bearing when I rebuilt the engine like 6 years ago...

 

[85_Ranger4x4]

I have Luk everything in mine, seems to work ok,.

The rear bearing retainer was worn pretty bad on mine. I replaced it before I put the trans in so I can't comment on if it made any noise or not. I think it would be under more strain under power though.

 

[scotts90ranger]

Just to follow up, I got the transmission out and somewhat apart (need an annoyingly deep puller for the rear output bearing...) and found out it's the tapered roller bearings on the input/output shafts, since I don't have it all the way apart I can't tell which yet but the input bearing doesn't look too bad so I'm guessing it's the output bearing...

 

[Shran]

They do make a steel rear bearing retainer plate to replace the aluminum one, might consider that.

I think the case on mine is messed up because it lasts about 2-3k before it starts popping out of gear. That bearing retainer is always worn. Doesn't make any noise but the bearings have always shown substantial wear.

I don't replace just the clutch disc, I do it all. Using a new disc with a used pressure plate is a recipe for premature wear.

 

[scotts90ranger]

I'm running a Centerforce clutch, you can only order it in parts, I spent the $250 and got both... I'll compare the old beat on stuff to see how well it lasted.

I'll see how tight things get with the new bearings when I get it apart, I'm not against making a shim to put behind one of the races to maybe help wear... but might look into that steel retainer... I need it back together within a month though with 2 camping trips in the mix before I need it together

 

[Shran]

I would be tempted to replace the retainer and just shim the input & countershaft bearings like you normally would. I don't know how adding any shims in other locations would help with wear.

On that note I'm not totally convinced that the steel bearing retainer is anything more than a bandaid - I've torn down a few M5ODs that were run dry and locked up and the factory aluminum bearing retainer looked perfect and showed no signs of wear. I don't see how a part that can potentially last hundreds of thousands of miles need an "upgrade."

Something in mine is sloppy and the bearing races spin and dig into the retainer though. I am just convinced at this point that the case is stretched or I'm getting poor quality parts or something. It would be cool if this transmission was designed with one more bearing on the main shaft to support it in the middle somewhere rather than relying on the input and pocket bearings to stay intact.

 

[scotts90ranger]

Yeah, relying on tapered bearings on a shaft with a pocket bearing in the middle to stay straight is an odd design, I forgot it was that way until I opened it up...

 

[scotts90ranger]

I confirmed tonight the noise was the rear tapered bearing, that thing was FRIED, some of the rollers were pitted and the inner race was destroyed and discolored...

I'll put it together before I decide to replace the rear bearing housing deal with the steel one, the outer race was definitely spinning but don't think it took out much material...