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[maracus]

I thought these v6 autos were 4 speed?? It's just that I keep counting 5 shifts. Even if you lock into 3rd afterwards it'll go up then up again. It's deffo in third because if you slow and lock it down a gear until 1st it shifts each time.

Is there an overdrive or some sort of splitter?

Or can I not count?

[albitz]

Something to do with torque convertor lock out. Dont know much about it but an intelligent person will probably explain shortly.

[aaronjb]

Yup - three speed with overdrive ('fourth' gear) IIRC, but the torque convertor locks up in 3rd and OD. Accelerate gently enough and you can count five 'shifts' - 1st to 2nd, 2nd to 3rd, lock in 3rd, unlock, 3rd to 4th, lock in 4th.

The shuffling in & out of lock at gentle throttle and up & down inclines is what makes the box seem like it's 'hunting' for a gear sometimes, as it can't change gear when the torque convertor is locked up, so you get: 4th with lock->unlock (revs go up)->3rd (revs go up again)->3rd with lock (revs go down)

[maracus]

Ummm- eh?? What locks?? Why? It will probably make more sense when I read it again later..

So it goes from a sloppy fluid connection to a solid locked connection???

I'm confused!!

[TheBoy]

Ummm- eh?? What locks?? Why? It will probably make more sense when I read it again later..

So it goes from a sloppy fluid connection to a solid locked connection???

I'm confused!!

Yup

[aaronjb]

Precisely that - at certain points (basically when the 'load' on the gearbox is low, or you're cruising at a steady speed) the two halves of the torque convertor will be physically locked together; so it behaves like a conventional clutch rather than a hydraulic coupling.

A physical connection is much more efficient than turning x% of the engine power into heat by churning the ATF up in the torque convertor 

[RobG]

Yup - three speed with overdrive ('fourth' gear) IIRC, but the torque convertor locks up in 3rd and OD. Accelerate gently enough and you can count five 'shifts' - 1st to 2nd, 2nd to 3rd, lock in 3rd, unlock, 3rd to 4th, lock in 4th.

The shuffling in & out of lock at gentle throttle and up & down inclines is what makes the box seem like it's 'hunting' for a gear sometimes, as it can't change gear when the torque convertor is locked up, so you get: 4th with lock->unlock (revs go up)->3rd (revs go up again)->3rd with lock (revs go down)

  4th gear is the "lock-up"

[aaronjb]

Yup - three speed with overdrive ('fourth' gear) IIRC, but the torque convertor locks up in 3rd and OD. Accelerate gently enough and you can count five 'shifts' - 1st to 2nd, 2nd to 3rd, lock in 3rd, unlock, 3rd to 4th, lock in 4th.

The shuffling in & out of lock at gentle throttle and up & down inclines is what makes the box seem like it's 'hunting' for a gear sometimes, as it can't change gear when the torque convertor is locked up, so you get: 4th with lock->unlock (revs go up)->3rd (revs go up again)->3rd with lock (revs go down)

  4th gear is the "lock-up"

That goes against what I've read here, previously?  Maybe I just misunderstood what I read.

[RobG]

Quote from the resident gearbox guru Sassanach
 "4th" gear IS the tc locking up.i am not aware of it locking in "3rd",please enlighten!  

[aaronjb]

AR35 is the 4L30-E, no?

It seems you're right that it doesn't lock up in 3rd, at least according to this bulletin: http://www.transtec.com/downloads/rebuilder_news/4th_q95r-n.pdf (page 5)

But both that and this say it has 4 speeds, not 3: http://www.transtec.com/downloads/rebuilder_news/2nd_q95r-n.pdf

Elsewhere I read that it's a 3-speed box (rear casing) with an additional overdrive (front casing) and lockable torque convertor (TC housing): http://www.unofficialbmw.com/images/BMW_Automatic_4L30E.pdf

http://scottj.info/files/isuzu/4l30e.pdf (another random PDF I found while trying desperately to find the first two )

[albitz]

Yup - three speed with overdrive ('fourth' gear) IIRC, but the torque convertor locks up in 3rd and OD. Accelerate gently enough and you can count five 'shifts' - 1st to 2nd, 2nd to 3rd, lock in 3rd, unlock, 3rd to 4th, lock in 4th.

The shuffling in & out of lock at gentle throttle and up & down inclines is what makes the box seem like it's 'hunting' for a gear sometimes, as it can't change gear when the torque convertor is locked up, so you get: 4th with lock->unlock (revs go up)->3rd (revs go up again)->3rd with lock (revs go down)

I make that six.

[aaronjb]

I never said maths was my strong point.. although we just decided it doesn't lock the TC in 3rd, so now we're down to four.

[TheBoy]

It is indeed the old 3 speed box with an overdrive unit bolted on the front (thus 2 sumps). 4 speed. Except for post 2001 Opel diesels, which are 5 speed.

The lockup is software controlled, and there are 3 main ECU types (ignoring the 5 speed one we don't have in the UK), each with varying software levels, so its feasible some may lock up in 3rd 

[Kevin Wood]

Mine certainly locks up in 3rd. And 2nd if you get the autobox fluid really hot.

It does have 4 discrete gear ratios plus TC lockup.

[maracus]

Thanks for that people, confusion solved!! Sorry I missed the conversation I got otherwise distracted.. I will have a read of those links so I can tell others how it works