Need to replace the transmission in my '85 325e...

[26kick]

Hi all,

I need to replace the 5 speed manual transmission in my ’85 325e and am starting to research how to and what I need. Here’s why it needs to be replaced:

When I got the car a couple of years ago, I wanted to change the gear oil as a matter of course. So I did my research and the verdict for my green label, male plug unit was Red Line MT-90. I put that in, no problem, as well as Red Line in the diff. Well several months down the line, I noticed that the shifting felt different and I could more noticeably hear the syncros working. So I got some more MT-90 and got under there to top it off if need be. Well, the fluid was nowhere near full so I decided to change it. When I drained it, not much came out. 8^O

Bottom line, MT-90 is thinner than the dino stuff that was in there and mine being a high mileage car, it all leaked out past the seals. Super bummed. EVERYONE uses the Red Line stuff, and no one has had this happen? So I carefully researched dino oils and found that GL-4 is the only option, which is hard to find. So I have the CRC 85w-90 in there. It’s a little hard to shift for the first mile or so, but once it warms up it shifts great. The problem is not the shifting, it’s the noise. The poor tranny whines like a stuck pig now. Even at idle “reerreerrreerrreerrreerr”, until I depress the clutch, and then silence. The bearings must have taken a beating and no amount of new oil is going to fix it. Again, super bummed. And it’s my own fault, which hurts even more.

I hope this story helps others to keep an eye on their gear oil after changing it.

So for my research, does anyone have a good DIY on R and R for a tranny in an old ETA? I want to cover all my bases before I get started and have all of the parts on hand. I plan on doing shifter bushings, guibo, tranny mounts, and a clutch kit while I’m in there. What else?

Now as for obtaining another tranny, I feel like I’m taking a risk pulling one from a yard, right? Not knowing the history of it is kinda scary as I don’t want to get it all back together and have issues. Should I be concerned, or is this what everyone does? On the other end of the spectrum, having mine rebuilt sounds expensive and time consuming. What do you guys recommend?

What am I looking for? Will any eta transmission work? Do I need to find an '85? Will a 325i tranny work?


Thanks!

[Ken@BavAuto]

Noise in neutral with the car idling foot off the clutch is somewhat normal in a high mileage E30. If it otherwise shifts fine and doesn't make a ton of noise, doesn't pop out of gear, etc. when driving I wouldn't worry about it a whole bunch. I would worry about it leaking though. If it's only leaking out of the back end of the transmission changing the shifter shaft seal and rear output seal should do the trick and this can be done without removing the transmission from the car. If you do actually need another transmission the 84-mid 86 transmissions are different than the later cars. The way the shifter connects to the transmission is different. I know it's possible to retrofit the early transmission to the later shifter with a bracket like the E30 M3 used because I have an 84 trans in my 89 right now. But going the other way would require swapping over to the later style shifter arm and all it's associated parts which can get expensive. You also need to keep in mind E cars have sensors in the transmission bell housing that 325i's don't have. Early 325e transmissions have a slightly deeper bellhousing too. For fluid I have never had an issue running Redline MTL in any of the E30 manual transmissions, early or late.

[Silverdogz]

If you do feel the need to replace, see what the prices are of getting it rebuilt. It could be cheaper.

[15Michaeljoseph]

If you do feel the need to replace, see what the prices are of getting it rebuilt. It could be cheaper.

and even if it isn't, it's worth knowing what's been done to YOUR tranny, and stuff like that.

[26kick]

Thanks Ken, 15Michaeljoseph, and Silverdogz, for the responses. I thought no one was going to respond! Maybe my post was a little wordy?

The noise is just a bummer for me and actually has started to make fwy driving annoying. I think it's getting worse over time. Plus I guess I'm just enough of an enthusiast, have the ability, and have just enough pride in my (wife's) car that I feel like I've got to do something about it. I'm sure y'all know the feeling.

When I switched to dino oil, it still leaked so I tried some lucas stop leak and have changed it out a couple of times. The leak has all but completely stopped, which is beyond my expectations. As part of this process, I want to do all of the seals, engine and tranny.

I hear you guys about rebuilding my unit. I totally dig that idea and plan to look into it. However I've already been to the junkyard and found a few candidates, all '86 boxes that have the sensors and I believe have the right shift parts. The yard wants $180 out the door, which is cheap so it's all about the labor. If it wasn't for the labor, I'd have done it already.

If you have any other thoughts, I'd love to hear them. Thanks.

[jagerking]

In my opinion, it is a good idea looking into used junkyard units. They cost roughly 1/10 of what getting a unit rebuilt costs, and there are tons to choose from. Even though swapping them is a fairly decent chore, I'd still rather DIY and save $1500 taking a chance on a used tranny. Check the fluid that comes out of the unit for color/metal (they're supposed to drain all fluids, but they always seem to miss BMW manual trannys), and check the shafts for play. Most yards will give you a 30 day "warranty" on parts, and will allow you to try another one if the one you got is bad.

[26kick]

Cool jagerking, that is the current plan. I talked with a local shop and they concur. I might go "pick" one tomorrow. Will check fluid, good idea.

[richardodn]

If the noise goes away when you step on the clutch, that is typically the throwout bearing. Without actually hearing the noise I can't comment on that further. For a transmission, you will want an 'e' transmission that supports the same shift arm style as your current one. You need an 'e' transmission to support the 2 bellhousing sensors. You likely have the black stamped steel shift arm but you should verify that by looking. (The other one is a cast aluminum one.) This is what Ken was talking about. Before installing, you will want to have all 4 seals replaced. This includes the input shaft, output shaft, selector shaft and detent cover seals. Additionally, now i a really good time to rebuild the shifter. Again you will need to know which style you have; stamped steel or cast aluminum.

[26kick]

Thanks. Picked up a unit at the junk yard. Now I've got to find the time to do it! It'll surely be more challenging on my car than a sacrificial yard car.

It's the t/o bearing if it's noisy when you step on the clutch, no? That's the only time the t/o bearing is in use. It's silent when I step on mine.

[dohcdoh]

Thanks. Picked up a unit at the junk yard. Now I've got to find the time to do it! It'll surely be more challenging on my car than a sacrificial yard car. It's the t/o bearing if it's noisy when you step on the clutch, no? That's the only time the t/o bearing is in use. It's silent when I step on mine.

If the noise goes away when you step on the clutch, that is typically the throwout bearing. Without actually hearing the noise I can't comment on that further. For a transmission, you will want an 'e' transmission that supports the same shift arm style as your current one. You need an 'e' transmission to support the 2 bellhousing sensors. You likely have the black stamped steel shift arm but you should verify that by looking. (The other one is a cast aluminum one.) This is what Ken was talking about. Before installing, you will want to have all 4 seals replaced. This includes the input shaft, output shaft, selector shaft and detent cover seals. Additionally, now i a really good time to rebuild the shifter. Again you will need to know which style you have; stamped steel or cast aluminum.

Richard already explained this for you, in his first sentence.

[26kick]

Cool.

I feel I was lucky to have found a transmission that fit all of the "e" criteria and also felt relatively "tight", compared to others I found anyway. I suppose I'll not know how it really is until it's in the car and under load. Fingers crossed.

Thanks Richard, for the details on what to replace. I'll start compiling a list and placing orders when I get my timeline together. Regarding gear oil, I know this has been covered many times, the one I got has no sticker and the yard drained it already. Ken mentions MTL above but I thought MT-90 was the thing to use. I'll have to do a search but I recall seeing that the sticker was mainly for topping off but if you replace the oil they all use the same thing, 75w-90 GL-4. Is that true? Thanks again.

[richardodn]

No label will typically use MTL. Green label gets MT-90 and red label uses ATF. But really any of these will work in the transmission. Try one and if the syncros shift smoothly then stay with it. Considering wear and climate on all these old transmissions, you can't really go by the original spec. MTL is a good place to start as it probably sits in the middle of these at 70W80. MT-90 is a bit thicker at 75W90. Try this if the shifting isn't smooth. ATF is a bit thinner and probably better suited for cold climates. However some racers use ATF as it doesn't foam so much.

[Jackson42]

You're probably going to be OK with the used transmission if it doesn't/didn't leak like your original. Despite some of the concerns about aluminum synchros, this is a really good transmission for the eta-powered cars - I've got 475,000 miles on mine and the only maintenance I've done is regular fluid changes and a selector shaft seal a while back. Don't be worried about a little noise in neutral - it's pilot and input shaft bearings, generally. I've used Lubrimoly synthetic gear oil all along - good stuff. Since you're in there that far, you might want to consider replacing the slave cylinder, throwout bearing, pivot pin and pilot bearing in the clutch mechanism and take a look at the clutch disk and pressure plate. And of course replace that selector shaft seal so you don't have a repeat performance. Good luck with it!

[Jeffnhiscars]

If your flywheel looks ok you still may want to consider removing it and replacing the rear main seal since you probably never get closer to it and with those miles I'd be surprised if it didn't leak somewhat

[26kick]

Richard, thanks for the breakdown on gear oil. Makes total sense the way you've laid it out.

Yes, I want to change the transmission and see what I got. When I do, it'll be the whole deal, all the seals, shifter parts, and clutch kit. Like you said, I want this to be the last time I get in there....if the tranny is in decent shape. I won't know that until I put a load on it.

I just finished doing rear wheel bearings today, see my thread on getting German parts on Sunday for the story. Yikes. Anyway, now I know that I had a lot of rear bearing noise and this made a huge difference. Now I can hear other stuff like the tranny more clearly. 8^\ This job made me notice that my CV boots are shot, so who knows what condition the CVs are in. Can anyone recommend their favorite replacement brand that balances cost and quality? Maybe I should start another thread for that one...

Thanks!

[dohcdoh]

Cvj axles will rebuild your axles, they do great work.

[26kick]

Ok, thanks. I'll contact Cvj.

[richardodn]

If the axles boots are just starting to crack but are otherwise in good order, you can probably get by with a clean and reboot. Do not bother with any of the part store reman units. I think they are almost all done by Cardone. And unless things have recently changed, Cardone uses the wrong outer boots.

Boot kit PNs: Inner-33219067895 ($33.29 ea at http://thebmwminipartstore.com), Outer-33219067810 ($31.79 ea likewise).
You'll need 2 of each. GKN/Loebro was the OEM for the axles. BMW or GKN and would be the preferred brands for boot kits.

As for having them remanufactured by CVJ, they do good work at a reasonable price. You won't need to send them anything but the axles.

[26kick]

Hi, the outer boots are completely broken/open. I would love to just do boots but I don't know how long they've been like this. However, I don't hear any grinding, especially now that my rear bearings are quiet. I hear my tranny going through the gears and maybe some diff noise.

I checked with CVJ and they're $169 each plus shipping which can't be less than $75 for both directions and probably almost two weeks with my car out of commission. They didn't have the parts in stock to do them at the moment either. I hear that there's a place here in Fountain Valley that rebuilds them but if the price is similar, I wonder if I should just get new ones and not deal with having to wait for them?

[richardodn]

The only new ones worth getting are original BMW and the best price you'll find are around $400 each. The cheap ones won't likely last more than a year or two. Here's another possibility. Check the big wreckers like bmrparts.com for a pair of good used ones. Order new boot kits. Reboot the good ones and swap them out in a day.

[Tom D]

If the noise goes away when you step on the clutch, that is typically the throwout bearing. .

I will respectfully disagree with you.

if the transmission is making a bearing noise with the transmission in neutral and the clutch engaged, but goes quite when you push in on the clutch peddle then the noise is from the input shaft and not the throw out bearing.