1990whiteI6

BACKGROUND:
I have the Mazda m5od-r2 5-speed in mated to a 4.9l in my 2wd truck. It is the original tranny and has 300,000 miles on it. As of now, is sounds as if one or a few of the bearings inside the unit are worn. There is the distinctive sound of bearing failure, mostly in first and second, tho I can hear it in 3rd and 4th (but not in 5th or rev). I can change the pitch of the noise moving the shifter to the left or right.

QUESTION:
I am getting conflicting opinions from area transmission guys. Some say they can rebuild it (bearings, synchros, top plugs) and I should be ok. Others are telling me that they wouldn't touch the unit with 300,000 miles on it. They say there is bound to be worn 'hard' parts inside and that I should look elsewhere for a replacement.

(1) Does anyone have any experience with these units to the above statements?

(2) If i should replace the unit, where can I find a new or factory rebuilt unit to purchase? I cannot seem to find any on the internet

I'd like to thank every one in advance.... tho the truck has 300,000 miles on it, it is clean and rust free. I'd hate to give it up because of this issue.

1990whiteI6

bump

farmer12

It's probably the tapered bearings on the top shaft. I rebuilt one for my 89 that came out of a 96. They're not to bad to rebuild. That shouldn't be a hard trans to find. You can use any that came out of trucks clear up to a 96.

1990whiteI6

Thanks for responding... When someone refers to 'rebuilding' a manual, do they just mean bearings and synchros, or should other items be replaced?

Oldrusty

I had what I thought were bearing noises in my '93, first,third,and fifth gears. Bearings were good,the noises were from the shifter itself, one of the pins that align the shifter had worked itself out . Replaced shifter bushings and pins,now quiet and easier to shift.

sylver91

One of these days I'm going to have to see what the chattering noise is on my transmission, I only get it it 4th gear and its been doing it for about a year. My guess is input shaft because of where the sound is coming from under the floor.

1990whiteI6

never thought of that... what type of noise did that make. i can change the pitch of the noise by moving the shifter around. however, it is louder when the unit is cold.

Oldrusty

Sounded like bearing chatter, and only made noises when shifter in forward position of shift patern 1,3,and 5, I didn't wiggle shifter around so didn't notice pitch change.

If your shifter is real loose and sloppy,replace the bushings and pins. Mine only has about 200,000 on it,and shifts like a new one now.