transmission rebuilds
 

I just had my tranny rebuilt and I have to say the experience has not been good. I had all the bearings and synchros replaced and had the case filled with redline. Now I did this because my tranny had 147,000 miles on it and it was getting a little sloppy. (grinding, noisy) I never expected to get the tranny back and find that it would louder then before. It sounds like it came out of truck. My mechanic states that the gears were not replaced and sometimes it is a crapshoot. The new bearings and synchros re-allign everything and the bearings have a certain amount of wear on them. For those of you that have rebuilt or understand transmissions can you enlighten me here. I am not sure if I am being sold something that is not true. It has merit and then I would think replacing at least the bearings would eliminate alot of the noise.

Later,
Dave

My trans rebuild finished yesterday. I got my car back and the mechanic told me that it might be a bit louder than you'd expect at first - there are some new gears and old gears in there, he said, and they will have to mesh with each other.

Don't worry too much if you have a warranty of any kind (as any reputable shop will grant you) because they know if there are any problems they will be replacing shit for free. When you pay someone upwards of 1000 dollars to rebuild the trans, they should try to do the job as well as they can, which means replacing everything that's bad. If they didn't replace a certain gear that was bad at the time of the rebuild, then to get that fixed if you need it should only cost you in parts, not labor.

I had my tranny rebuilt last year and it was nice and quiet when it was finished. It was whining like a mofo before I had it done. The countershaft and a bunch of bearings needed to be replaced. I think the previous owner let it run out of oil or something...

It makes a light whirring noise when just sitting in neutral, but while driving it is fine.

It seems to be a little harder to shift now, but I'm wondering if it will loosen up after I drive it for a while. I've probably not even driven 1000 miles over the past year (not the daily driver).

Re: transmission rebuilds
 

You never did mention the year/model of this tranny....with the miles, I'm assuming it's a 2nd gen. I rebuilt the tranny on my 90 non-turbo about a year ago and never had any problems. I've rebuilt other MTs before, but they were not Mazda. Unless a gear(s) has been damaged, it rarely needs to be replaced. Inspecting the gears and gear cones are part of the job when rebuilding a tranny. A rebuilt tranny, especially one that had high mileage, will never be equivalent to a new tranny when it comes to shift feel unless all new gears, synchros and clutch hubs and forks are replaced. The problem you've described sounds most likely to be bearing or clearance related. Unless the person knew what he was doing, a lot of things may have gotten screwed up. One possible thing that comes to my mind is that on the 89-91 NA trannys, Mazda changed the center countershaft bearing with one that was narrower (face-to-face dimension) than the original and did not offer spacers to compensate for this difference. When I did my tranny, I reused the original bearing because I couldn't figure out what the hell Mazda was doing here. This is perhaps one area to go back and question your mechanic about. Also, all the bearings are special bearings that are only available from Mazda. If you mechanic tried to match up bearings at a bearing supply house, than it may be that a substitute bearing is causing the problem. Other than that, don't know what to tell you. Good luck.

Larry Mizerka
90 Mazda RX7 GXL
02 Acura RSX Type S

lack of info
 

I appreciate those that have posted the unfortunate thing is that I am not sure what the issue is. My mechanic wants to pull the tranny and loan me a spare until he figures out exactly what is wrong. The amazing thing is that there is so much info on our cars. There is not alot of info on transmissions. The last post had some interesting information about the change in bearing design from Mazda. I wish I understood trannys more I think I would make it my section. There has to be more questions and answers out there.

Later,
Dave

THIS IS VERY IMPORTANT, you must coat (preferably Redline) each parts mating surfaces during assembly, especially those which turn on the shafts and all synchros and cones. Since the gearbox oil only covers the countershaft, when you first start the car you'll be running the mainshaft dry until enough oil gets into the gear oil ports and non-sealed bearings on the mainshaft. This could explain why a lot of people complain about louder rebuilt trannies when only the bearings and synchros are replaced. In some cases the damage is permanent.

it could be something dumb like the end play is incorrect, or something really dumb like something installed wrong.
the reason you dont see that many transmission posts is that most people dont understand how they work

mike

wooooah. Uh.. i thought that the whining noise was normal? It whirs pretty loud in neutral with the clutch out, and when going through the gears, it makes a pretty dominate whining sound (not so much in 4th and 5th as the other three.) It alsways made this noise, but it seemed to get a little louder after i replaced my clutch. Are you guys telling me that my Tranny has got 1 foot in the grave already? I gots an 87 GXL n/a and the person who sold it to me drove it like a grandma (basically she payed attention to the shift light) so i dont see how the 105k tranny should already be toast.

if your car was made before they updated the center countershaft bearing it could be ready for a new one

mike

hey guys,

for those that did the rebuild can i ask where u got the parts from and how much....i need to rebuild mine the synchros r shot....i would rather rebuild and know what i have vs buyin one and havin it go bad in a short time...is there someplace other than dealer or is that the best route?.....thnx