If I need to replace entire transmission, is there anything else I should do/get?

[Suay46]

I'm replacing the 5 speed RWD manual Transmission for my 2002 325CI and I want to know if there's anything else that I should or can do, to increase performance, longevity and stability of it.

The replacement transmission will be used (most likely around 60-70k).

[Muzz258]

How many miles on your car? If its over 100,000 I would be considering the following:
- new clutch: pressure plate, clutch plate, throw-out bearing and duel mass flywheel
- Replacing the rear main engine seal

[bluptgm3]

Why are you having to replace your 5 speed manual transmission?

I have 276K on mine, still going strong.…third clutch (second short life LWT FW). Others have probably done this with two OE clutches.

Shift slow and deliberate, you have plenty of torque to overcome any time lost shifting slow.

Transmission mounts, and brake/clutch fluid flush.

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[Suay46]

@Muzz258: 160k and thanks for the detailed reply. Couple questions (I know you stated for over 100k) but should I consider any of the things that you mentioned for this new transmission (it will have 73k on it).

If yes, should I be going to the BMW dealership or local shop to have this done?

Also, from the parts you mentioned, are there any specific brands that you would recommend?

@bluptgm3: That's awesome (wish mine would have had a better track record). I took it to the BWM dealership because the shifter would drop from 3rd to neutral (not all the time but for sure more frequently). They checked it out and told me that the internal synchros were worn. They then told me that I needed to replace the entire transmission for 5k or basically tow it to the junk yard ... lol insanity.

There were no other issues shifting (no grinding, thumping, chattering etc...) although the shifting felt "loose" i.e. felt easy to slip into other gears at times. When I took it to a transmission shop, even the tech said it wasn't really apparent of the slip from third to neutral: he had to drive for quite a bit it seemed to have it occur.

-brake/clutch fluid flush for the "new" transmission right? (with 73k on it) -should I take it to the dealer or a local for this? (I assume the former but want to be sure).

I think I will head your advice and shift slower.

Just out of curiosity, do you down shift to engine brake often?

[bluptgm3]

Shift detent pin are also a good idea.
https://www.bimmerworld.com/Drivelin...iABEgJLvPD_BwE

Down shifting to engine brake is forbidden where I am from.

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[Suay46]

^^ Thanks for the link, checked it out and the Detent Repair Kit looks legit but I don't see my model listed: 325ci -is it only for the 328 - 330? (seems strange)

"Down shifting to engine brake is forbidden where I am from."
-Really lol... is the transmission really taking a heavy hit from engine breaking? I thought the older models were equipped and in some cases, even required for such technique. *For sure I'm going to take your word, seeing as you've 276K and still going strong. Pass along your knowledge friend, I find your insight valuable.

[bluptgm3]

Validate your transmission model, the repair kit is for the ZF S5D 320Z.


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[KlausH79]

The transmission in mine did exactly the same when I bought it and when I asked the seller what might have caused it he didn’t know, but when I asked “do you rest you hand on the shift knob when driving?” He was like “well yeah...”

From what I’ve been told keeping pressure on the synchros with you hand on the shifter all the time is detrimental to them.

Regarding down shifting and engine breaking you can alleviate much of the synchro wear by double clutching.


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[bluptgm3]

Regarding down shifting and engine breaking you can alleviate much of the synchro wear by double clutching.

While a rev-matched heal-toe down shift is appropriate for this transmission it is not an acceptable practice, in most high performance diving circles, to accomplish engine braking.

A cars brakes are the most powerful system in your car, use them.
You are not saving any money by engine braking.

Engine braking places a reverse load on the rings, which they were not designed to support.


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