Ron_H

I just got my car back today after having the transmission rebuilt and woe is me. My '86.5 automatic had one trait that made me love it more than any other shark MY: it started in first gear from a dead stop with no other input from the driver. Then it would seamlessly shift into 2nd if the throttle load was light, but if the throttle was a bit more serious, it would remain in first until the throttle was lightened or it reached redline. But now it won't start in first anymore unless I shift it like Nicole's S-4, meaning dropping it into 2nd at the stop, and then shifting into 3rd and then back to 2nd to make it go into 3rd. What a drag !! Actually, it won't be much of a drag at all now since it is such a dog off of the line. Guess I need to take the transmission out again and take it back to the shop that rebuilt it and have them do it again. Does anyone know if their is an external adjustment that would remedy this awful situation??

It is so slow off of the line I think my Rabbit will beat it across the intersection. I have to get out and push it to get it going and then hop in. I expect to get a citation for obstructing traffic at a drag race for slugs.

bigs

Ron. I'm not a wrench, but I do know there is an adjustment cable, a simple tweaking of which may remedy your problem. In fact, I wonder if someone hadn't already adjusted the cable to allow a first gear start before you owned the car. I don't think such a situation is stock. So maybe your tranny guy just simply re-adjusted things back to stock thinking he was fixing a problem!

Now I'll be quiet and let someone who actually knows what he's talking about reply to your post!

Ron_H

Bigs, I hope you're right. I am already planning to remove the box and tear into it. That means another wheel alignment. Marc said there is a cable that adjusts the rpm at which it will shift, and it isn't shifting at redline now, but at about 5500 which isn't the same as before either. We were planning to adjust that and the modulator so it will slam into 2nd like it did before the rebuild. If shifts like a granny-mobile now, and I was falling asleep on the way home waiting to feel the shift.

Bill Ball

Hi Ron:

I believe the shift program is set by the valve body. Was that rebuilt?

Slamming into 2nd? That sounds like it may have contributed to the need for a rebuild. The shift whould be modulated and smooth (maybe not ganny-mobile) and not what I would describe as a slam.

Hopefully Steve Cattaneo will jump in and give you an educated opinion on the 1st gear issue. Your MY should start in 1st, as you know.

Ron_H

Bill, if I start out in first and give light throttle it shifts seamlessly, but more throttle and it shifts much more crisply and hard. Almost chirps the tires. My mother's 280 SL would shift like that, and 2nd gear shifts brought on a slight chirp from the tires.

Ron_H

OK, I just accessed Nichol's site and the transmission threads. I found that the transmission can be tricked into believing it must start out in first by adjusting the throttle linkages. Guess I'll hop to it tomorrow or Monday. Maybe it will work. Maybe Bigs is right and the PO did that. It surely was nice while it lasted and perhaps I can bring it back without too much pain. If anyone knows another way please share it. Thanks.

Asterix

Nichols site? Could you post a link please, in particular the transmission thread. Thanks.

Garth S

Ron,
Here's hoping that you soon rejoin the ranks of the shiftless .... ahhhh ... I mean the guys stuck in low gear .... ahhhh ... well, you know what I mean.
I would seriously doubt that the box need come out again: Hopefully it may be as simple as a control cable or modulator adjustment: however, if the rebuild was complete, the valve body is likely to have been disassembled and flushed clean: if one little springy thingamajig or ball check of the two quadzillion pieces ended up trading places, voila!
Bill has already noted the valve body - and to access it, only the pan need be removed: perhaps a monday AM call to your friendly rebuilder may help solve the mystery.
Dang, such a drag! - or not

edit: a rebuilt valve body may have been swapped in as part of the job ( for they are time consuming to do, and may be left for slow days) - and a S4 unit looks just like ....

chaadster

Ron H,

Your car should start in 1st in stock setup:

Excerpts from the 1988 Service Information Technik ...Spring of 1987....."in
the past cars with an A28 automatic transmission always moved off in 1 st
gear and shifted down into first with a noticeable jolt before stopping
while rolling to a stop . A changed shift program in the valve body now
makes it possible to also move off and roll to a stop in 2nd
gear for certain operating conditions . If the throttle valve is not opened
by more than 26 degrees while moving off the car will accelerate in 2 nd
gear.....another possible move off version acceleration is slow at first and
wide open throttle valve takes place at about 12.5 MPH the car rolls away
and shifts down into 1st gear at 12.5 mph . Then the shift up to 2 nd gear
then takes place at a road speed in excess of 31 mph"........ The changed
moving-off program was introduced gradually in spring of 1987 "......New
upshift and downshift program in selector lever position 2..."the car rolls
off in first gear and shifts down into first again briefly before stopping
while rolling to a stop. The braking effect of 1st gear is still effective
while coasting up to about 50 mph, before the car shifts up into 2nd gear."

Adjusting the linkage cable should do the trick, but just double check your throttle cable to make sure it's not too slack, too. If your throttle is not opening fully, that could explain some of the doggedly slow acceleration, too.

Asterix, the Nichols site Ron H mentions is very handy:

http://www.nichols.nu/tips.htm

Ron_H

Thanks all for responding. That will save me the cost of a shrink. Now there is hope in the world. I loved the original box and felt as if someone I loved had died. I'll check with the rebuilder shop tomorrow. And then its back to Devek for some adjustments. Life will be good again.

Steve Cattaneo

First gear starts, from a stop in a 928 and Mercedes Benz, is a design feature in the valve body, not the transmissions. I am not 100% sure if all pre 87, 928s came with a first gear start VB. from your operating description it sounds like a 1st gear start valve body to me.

A couple of possibilities: debris in the oil cooler from the flailed transmission got into the rebuild, contaminating the valve body, causing a 2nd gear start, stuck valves. Or someone install a 2nd gear valve body for what ever reason.

This is why I don’t like selling transmissions of any model car “over the counter”; the installation and set up is the second most important step in optimizing the shift points and feel.

The cooler line have to be flushed, cooler flow check, modulator and working pressure adjusted with a gauge, and the TV cable adjusted on a road test. A dyno transmission can NOT replicate the load and driving experience of a real road test.

Ron, if you need any advice let me known.

rob rossitto

hope your case is different, but on my last rebuild I had the same problem - turned out to be the clutch packs were wrong versions, and shifting was a mess... had to pull it out, use correct parts and after messing w/the valve body (3 different units) finally got the right setup... sometimes these guys grab parts that look the same, but turn out to be wrong - after they put it back together and say it's fine, have a nice day...

IIRC, the modulator controls firmness, but the shift kit I installed seemed to do almost the same thing as just reducing modulator adjustment... also watch out for the vac line to the trans - if it leaks shifting gets too firm...

I'd probably try adjusting stuff 1st anyway... it's a lot easier than the alternative and if you can't adjust away the problems, you'll probably have a better clue as to what is messed up...