Tony

What speed where you doing?
under 60ish odds are in 1st..if you were above that to 90 something probably 2nd.
GTS gearing is differnt than the S4 but your speed would be the biggest clue to gear.

Like CMW said...now add 120 HP from a SC! Stomping on it in 2nd gear at 60 i have to watch traction

Ron_H

My '86.5 starts in first every time. If I ease away from rest, it shifts almost imperceptibly into second, and then as it would normally, shifts into 3rd seamlessly. But stomp on it from rest and it stays in first and then at redline, it hops as it shifts into second and nails you down into the seat. Or you can give about half throttle from rest and it stays in first until about 4000 and then shifts crisply into 2nd and chirps the tires if I am on a slight curve or spins them on wet pavement. I love my '86.5 transmission.

bigs

928Quest's post sounds most like what I experienced. And, come to think of it, I did slip the gear selecter down into "2" just as I was coming to a stop at the red light. When I tromped it, I was going maybe 20 mph. And there was no doubt that I was in first!

What it makes me wonder is if all the other times that I've blasted from a standstill with the selector in "2" maybe I really was in 2nd gear rather than first. Is manually placing the selector in "2" a guaranteed way of getting the tranny into first gear? Or does it sometimes work and sometimes not?

Tony

In an S4 it seems to be a guarantee. Im not sure why a GTS would be diferent?

ROG100

Bigs,
That is what I was trying to tell you.
Look at my posts.
select 2 then back to 3. This will hold 1 until the limiter kicks in or you select 3 and back to 2. that changes you to 2.
Roger

Randy V

My car when shifted to 2 at a dead stop, upon quick acceleration stays in 1st until redline - I have to shift to 3 to get to 2nd, then quickly shift back to 2 to hold it in 2nd to redline.

ROG100

Randy,
You may be right I have not taken my car out to try it.
You say "red line"
Do you mean the limiter?
IIRC if I select 2 the start is in 1 but the auto makes the change at redline.
Select 2 and then back to 3 and try that - you should hit the limiter in 1st.
The only way to select 2 is to select 3 and back to 2.
Roger




Roger

Shark_gts

'93 is a tweaked trans from 90/91. Pressures are higher and the TC has changed to handle the higher torque.

My car will always goto 1st in "2". On the GTRSS (Kickdown) Button, I can pull first easily in "D" by being a little more aggressive on the throttle. I can also hold 1 and 2 much higher, per the spec for k/d mode. This is quicker and more fun than shifting, which I still do.

I still am experiencing an occasional annoyance with B1 on downshift, which engages for 2nd gear. If the car is going slowly (especially after a RH corner) at about 40 km/h in "D" (4th) and I nail it, I will get a hard grab as there is a delay from the time K1 dis-engages to when B1 pulls in to establish second.

heinrich

Dude what are K1 and B1 etc?

wds928

Randy V has it right for the GTS. Shift down to 2 at the light. Once you take off, upshift to 3 and immiately back to 2 in order to get into 2nd gear, then upshift to 3 to get into 3rd gear. Kind of like working a manual gearbox without the clutch. I believe the the computer senses driving patterns and will change shift points to a certain extent.

I drove mine this past weekend in an autocross, starting out in 1st gear and letting the readline take care of shifting to 2nd. I just left the darn thing in "2" and let the trans do the shifting, I concentrated on left foot braking and holding the right foot down. Kinda hard on tires, but what a rush, just hanging on to the steering wheel.

Shark_gts

The K's are the clutches and the B's are the bands. In the Merc, there is K1, K2 and B1, B2 and B3.

The bands are a like a drum brake shoe but with a lining on the inside radius. They are piston actuated and grab the the ring gear of a planetary gear set.

Simplified....
1st* - B2; 2nd*- B1&B2; 3rd- B2, K1; 4th K1-K2; Reverse B3 and K2.

*K2 is applied if "2" selected for engine braking.

There is no computer that controls this tranny. The computer is purely vacuum &mechanical, with the exception of the relay.

heinrich

Shark ... maybe write a lot of knowledge like this up for us neophytes?

bigs

I second that, Shark. Your post was fascinating, but I'm still scratchin' my head about some of it. Give us a little longer, more detailed post about how the 928 tranny works - something a guy can print out!

TIA

bigs

My tranny must be different.

If I shift into 2 at a dead stop, then accelerate quickly, the tranny will stay in first until redline, then automatically shift into second without hitting the rev limiter and without me even touching the gear selector.

And it will stay in second until redline - again without me touching the gear selector - at which point I then have to manually move the selector into 3 - or I presume I'd hit the rev limiter... haven't taken the revs beyond redline yet in second.

But I don't have to do any of the "2 to 3 then back to 2" stuff. Although, apparently if I did, it would stay in first until it hit rev limiter without the automatic shift into second.

But I don't see any advantage in my car to doing all that fancy shifting. If it will shift automatically from first to second at or very near redline, I see no point in holding it in first to gain no more than maybe another 100 rpm or so at which point I'll exceed redline, be cut off by the rev limiter, and lose power.

BrianG

Shark_gts

Is there a resource that I can locate to learn about this automatic transmission, and it's variations in 928 applications? I understand that this is essentially a Mercedes transmission which is/was a very common unit. In that it is a ubiquitous model, there must be much information around on the thing.

For the early S4, I'd like to discover how likely it would be that once could revert it's function to that of the earlier cars, like the 86.5 car. Specifically, I would like to have 1-2-3-4 shifting as the default "D" pattern, and I'd like to have full manual command of 2nd and 3rd, and a facilitated downshift into 1st (as with a throttle blip) for engine braking. This is the current standard operating of my 86.5 car. Either basic throttle body modification, like found in the B&M transmission kits for many non-electronic North American transmissions, OR perhaps a discovery of the value of a transplant of the whole throttle body from the earlier version.

Your comment would be appreciated.