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-   -   94' GTS AT skipping 2nd gear... from what I can tell (https://rennlist.com/forums/928-forum/1138000-94-gts-at-skipping-2nd-gear-from-what-i-can-tell.html)

x98boardwell 04-10-2019 09:59 PM

94' GTS AT skipping 2nd gear... from what I can tell
 
Car had transmission rebuilt in 2009 at 100k miles. It's been driven 800-1000 miles since. When I purchased the car a little over a year ago I pulled the motor and did a complete refresh and upgrades at that time along servicing the transmission. The only thing I didn't drain at that time was the transfer case. I did change the filter out and a new gasket.

Unsure where the trans was rebuilt but local shop outsourced from the central valley area. Apparently reputable shop but I'm having trouble finding the paperwork. The previous owner went and had it printed off so I have it somewhere.

Since then I've driven roughly another 1000 miles including Rennsport this past August, 2018. All fluid levels are checked when hot on level ground and just below the "full" line when in park or neutral.

The symptoms are below:
- When cold, it seems to shift normally and from what I can tell hits all gears (including 2nd), but only lasts in my neighborhood, which is maybe 1/4-1/2 mile with a couple stop signs.
- When hot it tends to stay in 1st longer than normal (maybe as 2nd isn't available) then jumps to 3rd, again from what i can tell. 1st revs up very quickly and is a short gear so my thought is that I'm correct on the assumption. The other reason why I feel its missing 2nd and going straight to 3rd is the massive RPM drop between shifts, typically from 4500-5000 down to 2000 (rough estimates here) but you can imagine how that would feel dropping so much its like your out of your power band and have to start all over. This happens under hard or light acceleration. The difference with light acceleration is that it shifts to 3rd quicker even lowering the RPM's once in 3rd. I can count the other gears so 3 total with missing 2nd.
- When hot and attempting to upshift (3rd to 2nd) and mashing the throttle enough it wants to jump all the way to 1st which would be too high of revs.

Question,
- when I put the gear selector in 2nd it starts out in first and at what RPM would I need to be at to force that shift into 2nd if I never moved the shifter? If it doesn't go what next?
- Does the B1 or B2 Valve body have anything to do with this symptom and could maybe that be fixed to address the issue?

Thanks for any help. I've searched endlessly and nothing seems to pinpoint what I'm referring to except a post from 2005 where he thought the trans may need a rebuild but never updated the thread.

Bryan
PS. Car drives great otherwise! Pics attached.
https://cimg0.ibsrv.net/gimg/rennlis...27090ef455.jpg
https://cimg2.ibsrv.net/gimg/rennlis...ae79c21c56.jpg
https://cimg4.ibsrv.net/gimg/rennlis...adb6b13f97.jpg

GregBBRD 04-10-2019 10:05 PM

OK.

I'm going to leave this alone and let you guys straighten him out.

Someone send me a PM, if I need to get involved.

x98boardwell 04-11-2019 01:26 AM

Greg, what am I missing here? is it that simple? I know it can't be the Bowden cable as its missing an entire gear. Unsure what you mean by "straighten him out" but please elaborate if you are able.

From what I found the B1 & B2 valve/valve body or spring has something to do with the 2nd gear so want to be sure it isn't a something I can do without removal.

I thought I was asking a legitimate question after searching for days and coming up empty handed.

928Myles 04-11-2019 04:06 AM

Hi,
does the behaviour match the diagram below? The auto will normally start off in second.

https://cimg5.ibsrv.net/gimg/rennlis...1ca4cc96d5.png

polecat702 04-11-2019 04:40 AM

The 4 speed automatics, all start out in 2nd gear. Unless you floor it, then it'll start out in first. There's a video, on how to manually shift the automatic, but I don't believe in abusing my car, and I don't track it ether.

928 GT R 04-11-2019 06:58 AM

Beautiful car! What else is in your garage? :rockon:

Perhaps if the shift points in the above map do not sync with your observed results, you could post your actual engine revs when it shifts or a video of your symptoms.

mike77 04-11-2019 08:37 AM


Originally Posted by polecat702 (Post 15765793)
The 4 speed automatics, all start out in 2nd gear. Unless you floor it, then it'll start out in first. There's a video, on how to manually shift the automatic, but I don't believe in abusing my car, and I don't track it ether.

My S4 always starts in 1st if I stop at the lights and put the shifter to 2. It will appear to hold first until I move the shifter up.

captainOCD 04-11-2019 08:44 AM

My 86.5 starts in first anytime I'm at a complete stop.

x98boardwell 04-11-2019 10:47 AM

Thanks everyone, I have been using the shifter as a manual option (shifting it from 2nd to 3rd, etc) occasionally to see how the car acts. I do feel it's starting out in 1st all the time, no mashing needed. Based on the diagram from 928Myles its definitely 1st based on RPM vs. speed. As mentioned above, maybe its starting out in 1st more frequently as 2nd isn't available and would need to start in 3rd, especially when I'm starting in the 2 position on the shifter, but I believe its starting in 1st when it's in D as well. Good to know others are starting out in 1st. My previous 928 did what polecat702 mentioned but this one is definitely 1st most/all of the time.

Anything else I'm missing? Happy to take a few videos when cold vs. hot as well to show symptoms. May take a day or two to have time to do this though.

mike77 04-11-2019 12:44 PM

I don't know if my S4 has been somehow modded in the past. As I've said above if I drop to 2 at the lights at a standstill from either 3 or D it takes off in 1st. It then appears to hold first. If I want to move to second then I move the gear stick quickly from 2 to 3 and back to 2 again. It will then hold second until I shift to 3.

Try quick shifting from 2 to 3 and back to 2 and see what happens.

76FJ55 04-11-2019 02:00 PM

The first to second gear start change occurred mid 87. All early 4 speeds started in 1st, then later 4 speeds incorporated the 2nd gear start. A later trans should start in 1st if manually shifted down to 2, and should hold 1st to about 5800 RPM before shifting to 2nd unless you are floored and the kick-down switch is depressed, in which case it should hold to redline. to manually control the 1st-2nd shift you can do as MIke77 suggests and move temporarily from 2 to 3 and back to 2. the temporary pause in position 3 will allow the trans to shift to 2nd, and you immediately put the shifter back into 2 to hold second gear. You can then control the 2nd-3rd shift by moving the lever to 3.

x98boardwell 04-11-2019 02:30 PM

Update, thanks for chiming in Mike, I never thought to go back to 2 once it changes to 3rd gear. Just drove the car to see what's happening and if that would force 2nd to engage.

- When shifting from 2nd-3rd (which is really 1st-3rd) then back to 2 it does try and go into 2nd but seems to be slipping. This is the only time I've been able to find 2nd. It then shifts back into 3rd right away as I relax my foot on the throttle due to slipping and rpm rev.
- when in 3rd gear (D position on shifter) under harder acceleration at lower speeds is jumps 2nd and tries to engage 1st.
- when in 4th gear (D position on shifter) under hard acceleration at higher speeds it engages 3rd perfectly and runs well.
- once at a stop, it always starts in 1st and jumps to 3rd
- if speed is low it will stay in 3rd and that is how you will take off from lets say 10mph and above if you don't stop but just slowed down.


What could be the cause of 2nd gear not engaging and slipping when forcing it into that gear from the 2-3-2 shift which has been the only way I've found 2nd...

Thanks everyone!

polecat702 04-11-2019 02:36 PM


Originally Posted by mike77 (Post 15765911)
My S4 always starts in 1st if I stop at the lights and put the shifter to 2. It will appear to hold first until I move the shifter up.

Mine does too. Put it in drive and it starts out in 2nd. That's the way they were set up from the factory. If Doc Brown, rebuilds your automatic, he'll reprogram the tranny to start out in 1st if you like. My 928 is supercharged, it pulls just fine in 2nd from a light.

76FJ55 04-11-2019 02:37 PM

Try disconnecting the bowden cable and driving it to see how it reacts. it should be a 2nd gear start and then progressively shift to 3rd and 4th. If you have the shifter in 2 the highest possible gear is 2nd, no matter what the load is or RPM it will not progress into 3rd. You should then be able to manually shift between 2nd 3rd and 4th by positioning the lever in 2, 3 or D.

James Bailey 04-11-2019 02:45 PM


Originally Posted by x98boardwell (Post 15766684)
Update,


What could be the cause of 2nd gear not engaging and slipping when forcing it into that gear from the 2-3-2 shift which has been the only way I've found 2nd...

thanks everyone!

Perhaps you should talk to the shop that "rebuilt" the transmission to see if they altered it to start in first and then inquire about the second gear issue if it is in fact starting in first all the time..


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