The tranny has recently started making noises, first I thought it was the throw out bearing but I am afraid it is more than that. As I go thru the gears the trans makes rattling/grinding sounds: in 1st, 2nd, 3rd and 5th it is loud but 4th it is quiet. Any ideas on what might be going on inside the tranny
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Thanks

 

Check the oil level. These have plastic/rubber plugs up top that leak just enough to cause problems over the long haul, but not enough to leave a big mess that you would notice.

Check under your carpet for an access panel. If you have one, you can pull the top of the trans and inspect the shift forks and general condition of the trans.

If you are low on oil and have started the process of bearing destruction, you have little choice but to eventually pull the trans and replace the bearings, synchros and anything else that shows wear.

M5OD Mazda Design Manual Five Speed Transmission Preventative Measure .: Articles

 

A bearing would be my guess

 

thanks for the ideas, i will check it out. adn just to get an idea on how much it would cost for a rebuilt tranny i called a local shop they wanted $2200, installed and if i did the R&R it was $1800 that is CRAZY!!!!! Hell the blue book on the truck isn't even that much. anyone suggest a good place to get a used one

 

Normally grinding and noises in all gears, but 4th points to bad input shaft bearings and/ or bad countershaft bearings.

Josh

 

would replacing these bearings need special equipment or could i do it at home?

 

Best to start calling salvage yards for prices on a good used trans, most have some sort of short term warranty/guarantee on used units...........Tearing down and rebuilding even a manual gearbox is not something most folks want to tackle at home.

 

If the noise persist in 1st, 2nd, 3rd and 5th the then pocket bearing between the input shaft and the mainshaft is wore out. The pocket bearing allows the input and mainshaft to run true with each other. The mainshaft gears and countershaft are meshing together a little more than usual, which is making the noise you are hearing. It does not make that noise in fourth as it is a 1:1 without the countershaft being utilized. Do check oil level the pocket bearing often fails when the transmission is run low on oil. If it is low and you still have the rubber plugs on the back end of the shift rail then they are probably leaking. If you decide to rebuild the transmission yourself you will need a main bearing kit (will come with everything you need bearings and sychro's as well as the shift rail plugs which are metal). You will also need the input and main shaft's which are purchase seperately from the bearing kit.

 

are Mazda tranny's interchangeable with the one i have?

 

Internals yes, but you have to use the mainshaft gears with the lower cluster from the same transmission unless the tooth counts are the same. Some are geared different like the 3.0 M5OD, which have a lower first gear. The housings/bodies are not interchangable. The 2.9 and the 4.0 share the same bellhousing but the 2.3/5 and 3.0 are two totally different animals in themselves

 

The Mitsubishi trans in my '88 started being noisy like this.. found a good one to replace it at the local junkyard for around 90 bucks...came out of a 90 bronco II.. the 2.9 in the b2 was also good.. got that too

 

That price is unheard of around here. I'd buy them all day long for 90 bucks. Was the transmission in your 88 an M5OD-R1 or the FM146? They are both built but Mazda but two totally different transmissions internally.

 

give this a try http://www.car-part.com/

 

What kind of fluid did you put in it? How often was the fluid replaced?

 

Mine was an FM 146..The local junkyard (Ecology auto parts) has pretty reasonable prices.. heck, a whole complete engine is 189.00+core charge.. they used to be 169.00 until f'in cash for clunkers...have to find and pull the stuff yourself though...i dont mind.