how much abuse can a slush box take?

[mlytle64]

i have to instruct at a pdx in two weeks. both my m3 and m2 are down. the shear entertainment value of running in the instructor group with my stock eta auto commuter car is enticing....

but...can the 4hp22 auto tranny take that much abuse?

[Sagaris]

Kamotors has certainly abused his trans more than I ever abused mine so he should chime in as well :P

When I got my car it didn't look like it had been abused, but it was certainly neglected and im not sure how well the previous owners kept up on fluid changes. I got the car (91 325i auto) off ebay for 1500 with 185k on it and knew that some German cars had terrible automatics (VW mainly) and was expecting the ZF unit in the E30 to be made of glass also. The first day I had the car I changed the trans fluid to some Valvoline MaxLife. In the few years I have owned it I have put about 10k miles on the automatic (now 195k) and flogged it often. At the risk of sounding like a dork: I manually shifted it >50% of the time because I didn't like the early shift points and couldn't resist the sound and feel of taking a BMW 6 up near redline. After getting the engine up to par the trans could chirp the tires going into 2nd (fresh Falken 912's). I never did donuts or tried launching the car from a stop, but it was mainly just a lot of hard acceleration and manually shifting from 1st to 2nd near redline and occasionally got the back end out of shape on some corners for the lulz. As much as I wanted to wait til the automatic died to do a 5spd swap, I just didnt see it failing anytime soon so I gave the car one last hard drive as a slushbox and swapped it out.

The transmissions do have a defect that can cause failure if you rev the engine in neutral/park due to a pressure buildup wrecking one of the seals (google it) but I say if the unit has fresh fluid then go enjoy yourself, and just remember that if you DO wreck the trans, there are people like myself that would let a healthy one go for $50

[M-technik-3]

Marshall,

Do you really want to be doing a transmission swap in the next month or so? I don't think I would subject a 25 year old auto to a day of instructional track duty. Has it ever been rebuilt? Last fluid/filter change on it?

[nando]

I beat the shit out of mine. I couldn't kill it. I don't think a track day (with an eta motor) is going to kill it. It's not like the eta is so fast or powerful that you're going to be pushing the trans to the edge. just make sure the fluid level is good. valvoline maxlife is a great fluid for these transmissions, it made a huge difference in how mine shifted.

The only sure fire way to kill one would be to rev it in park or neutral, or run it dry of fluid. I did everything I could - 3 years of 1st gear autox runs, constant shifting (up/down), etc. People only think they are weak because of the design flaw mentioned above.

I'd probably leave it in 3rd gear, which is 1:1. it will still shift 1-2-3 but won't go into overdrive. it will make it a little less painful to be on track with an eta automatic. :p

[mlytle64]

thanks guys. car has 158k on it. trans was replaced with new one by bmw when the car had 30k on it. (i have all the service records since it was new) no idea why it was replaced. all maint is current. i have put about 7k miles on it in last 4 months and the thing runs great. i normally stay far away from auto's, but this thing showed up as a stray last fall and has been perfect in the DC traffic i commute in.

i would swipe my wife's e46 325it auto for the event, but i want to stay married...

no, i do not want to do a tranny swap!

[Bearmw]

Some have run turbo M30's in E28's with an auto and had it survive but I don't know if any internals were beefed up.

[kamotors]

the 4hp22 can just about handle anything below 7 psi. I've done tons of donuts/drifts burnouts and the only thing that made it start to die was when I turned up the boost.. now it simply cant shift quick enough and just slips into gear changes which is no fun. You will be fine for track days.

[mlytle64]

well, it survived. put it in "S", floored the gas and ran laps for 20min. repeat 3 times. zero issues.

[M-technik-3]

S? non of my old slush box iS had an s designation. Glad it still gets down the road. Weather must be perfect right now in NoVa.

[mlytle64]

the "S" is where a "3" would be. maybe mine is "special"....;)

at end of straight i was at rev limit in "S". good thing it couldn't go any faster!

yes, wx was perfect. sunny and 60!