Howdy all,

I have recently purchased my 2nd S4, nine years after selling my first. Man, I wish I had the resources of the internet the first time around!

I have a question about my car I hope you may can help with. The automatic tranny seems to upshift very early, particularly in first. The tachometer is inoperable (which after doing some reading on here I feel is likely a corroded connector issue, to be tackled probably this weekend), but to my ear it upshifts around 4,000-4,500rpm when the petal is on the floor. In any case, it shifts MUCH lower 1-2 than 2-3. It also feels sluggish to downshift. Shifting manually seems to not have any effect (of course, there is no "1" position).

What controls the shift rpm? Is it an old-school kickdown cable of some sort, or a vaccuum module, or german voodoo? Is there some way to adjust it?

Just about the moment I get into "fun time" in first, it kicks up to second and kills the moment. HELP!!!

OK, I know it's not a big problem, but I sure would like to know how to fix it!

TIA for the help.

Brian Flanagan
Fastech Auto Brokers, LLC

 

I'd bet it would respond to an adjustment of the Bowden cable. Just don't ask me where it is or how to adjust it. Someone else will chime in and give you the details. Or you can do a search for "Bowden cable."

 

Have your passenger grasp the shifter and firmly squeeze it just before it shifts.

 

See? I toldja someone would chime in with the details!! We're nothing if not helpful here.

 

Auto Brokers in a nice way of saying used car dealer. How much do the S4s go at the dealer auctions these days? Getting ready to flip the S4 for a profit?

Ohh I almost forgot, wellcome to the bard.

 

Brian
Good to see another Brian on the board!

My guess is also an improperly tensioned bowden cable and (possibly) a bad kickdown switch. If the cables haven't been adjusted in a while (likely) that could be the cause.

My S4 had the cables retensioned after a rebuild last year & it responds far faster than my friends 87 S4 auto...especially to kickdowns!

 

Actually bought it off the 'bay! They are few and far between at auctions, and tend to be either completely used up or relatively expensive... or both...

No, I have been in love (lust) with the 928 since my formative years.... I remember admiring one an older (richer) student had when I was in 7th grade... he was a senior, and had a black '78 or '79 (this was in around 1979-80), god I was in lust!

Comes from growing up in the "Risky Business" era, I guess, as most of my friends of a similar age seem to suffer similarly!

Thanks for the help.... there will be some actual help coming, right? (LOL)

Brian Flanagan

 

AAAhhhhh!!! The old Bowden cable, I see, I see! (scratches chin thoughtfully, pretending to understand...)

Thanks for the help. I will do some searching about this bow down cable thingy!


Brian

 

Found this old post while searching:

"Brent,
I totally agree with you that the manual drive shaft with its three support bearings would be stronger then the automatic with only two support bearings. But as to the transmission its self, the automatics can absorb and transfer more torque then a manual. Even with the automatic drive shaft being weaker I doubt the cause of failure was a 1st to 2nd shift at 4500RPM


The US autos were set up to shift at 4500/4800 RPMs for fuel economy. It is not hard to raise the full throttle up shifts. A simple adjustment on the valve body will do it.

Tim,


TV means throttle valve, a shift timing valve controlled by a cable on the engine. Make it tighter and the up shifts will be later to a point.
__________________
Steve C
928S 83
The Great White928
85 S2 EURO
02 MB AMG "

So it appears the autoboxes upshift around 4500 rpms by design, which jibes whith my aural tachometer. Is this similar to you guys' experiences? If so, how does one adjust the valve body? Is Steve C still on the board, and should I bug him for answers?

I hate being a newbie! But ya gotta learn somehow! Thanks for the help guys. You rock!


Brian Flanagan

 

When I first bought my AT 928, it had symptoms very similar to yours. I believe the previous owner had the Bowden cable adjusted extremely, such that the car actually started out in first gear rather than second - which is the normal mode for an AT 928.

It was kinda interesting to have first gear torque starting out, but like yours, it shifted into second almost immediately.

You might count the gears as your tranny upshifts with increasing speed. If you feel three shifts, then you're starting out in first gear.

 

Brian, if you do a search for TV cable I'm sure you wll find what you are looking for. I believe the adjustment is on the side of the throttle bell crank. On my 84S' there are three cables. The cable from the pedal, the cruise control cable and the TV cable. If I read previous posts correctly you adjust until there is no slack in the cable with the throttle in the closed position.

 

Flanagan,

As was mentioned above, you probably need to tighten/remove slack from your trans cable. Alongside your intake manifold on the drivers' side, you'll see the cable mounts; the outside, upper cable is the one you want to tighten up. It's got adjuster barrels on the mounting plate and at the firewall. Here's a pick from Tony's most excellent site to help you ID it: http://members.rennlist.com/v1uhoh/underthe.htm

You may want to check the function of your kickdown switch as was also mentioned above, and add a kickdown bypass switch. Again, Tony is the man for more handy info: http://members.rennlist.com/v1uhoh/kickdown.htm

A bit of fiddling should get you scootin' proper.... yeah, scootin' proper, that's the ticket!

Welcome on, mate!

 

AWESOME links, Chaad! Very helpful, I appreciate it greatly. I will play with the adjustments as soon as I have time- today or this weekend.

Does anyone know if any of these adjustments will affect the rpm of the 1-2 upshift? That is my main quest right now.

Thanks to all for the great help!

Brian Flanagan

 

They certainly will affect the ripm of the 1-2 upshift. In fact, if you over tighten the cable it won't upshift at all!

BTW, if your car is shifting properly, you should able to manually select gears with the shifter.

I think that what most folks do is adjust the cable until the car is shifting how they like, then use the kickdown bypass to downshift at partial throttle input. I'm sure that some of the more knowledgeable cats around here can explain how the two adjustments interplay.

Hey, how about some pics of the new ride?!

 

I can indeed shift manually, to an extent. When the lever is pulled down into 2, the tranny still upshifts from 1-2 very early, which is what my question was about. It will then hold the rest of the gears as I dictate by moving the lever. I am intending to perform the kd bypass or install the Jaeger bypass/shifter deal, but I want to be sure everything else is up to snuff first.

Thanks again for all the advice. Pics will be coming soon... at the 20 ft. distance necessary to make her still look like a queen, of course!

Brian Flanagan