Not downshifting right, speedo fluctating
Thread Starter
Staging Lane
Joined: Sep 2015
Posts: 51
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From: Hugoton,KS
Not downshifting right, speedo fluctating I have a 2000 z28 a4 which I bought a few weeks ago and it just doesn't feel right. It holds first gear until exactly 15 mph and then finally shifts into 2nd under normal throttle and I also notice it kinda of shudders. Other gears it shifts just fine. When I go from say 20 mph it will downshift but only to 2nd gear. I noticed that if I put it in Drive (third from bottom), it will downshift to first. The Speedo also fluctuates up and down about 10mph when I do that. Speedo also does that in overdrive but not as bad, only once I get past 60ish making a pull. On the highway just cruising it will also fluctuate more so when I go 70mph or around there.
It seems to lock up when I'm just cruising but on the highway I never feel it lock up. I'm around 2100 rpms going 70. The car is factory 2.73 gear but I don't know it has been swapped out. Doesn't feel like it. What do you guys think this is a trans problem or sensor/wire. Car doesn't feel that fast either, especially top end. Mods are full exhaust, volant cai, ls6 manifold, milled 862 heads, frost tune. To give you a perspective I'd be iffy putting this against my old 2v Bullitt.
It seems to lock up when I'm just cruising but on the highway I never feel it lock up. I'm around 2100 rpms going 70. The car is factory 2.73 gear but I don't know it has been swapped out. Doesn't feel like it. What do you guys think this is a trans problem or sensor/wire. Car doesn't feel that fast either, especially top end. Mods are full exhaust, volant cai, ls6 manifold, milled 862 heads, frost tune. To give you a perspective I'd be iffy putting this against my old 2v Bullitt.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
Trans does part throttle shifting off pedal position and mph. Mph is obtained by the speed sensor in the tail of the transmission, and pedal position by the throttle position sensor on the throttle body. I would look to those two sensors first. Having a trans shop run a diagnostic is a good idea.
Thread Starter
Staging Lane
Joined: Sep 2015
Posts: 51
Likes: 0
From: Hugoton,KS
The tps is only a couple months old but I'm not too sure about the vss. But yeah I've been trying to find a scanner that will read live data to see what's wrong. I've scanned for codes and there's nothing.
