1995 SOHC Automatic transmission issue

[Dirk Albring]

Consistently, or at least until the car is good and warmed-up, the transmission acts as if it slips at 20mph. I mean, you can watch the speedometer and know that right when it hits 20mph it feels like someone stepped on the clutch of a manual transmission while their foot was still on the gas; almost like the clutch is slipping, but this is an automatic transmission. One of the guys at worked suggested it might have a vacuum controlled "shift modulator" whose diaphram could be on the fritz. Anyone got any ideas and/or ever experience this? Thanks in advance.

[Mic1980]

I have a similar problem with my 97. I read here that some chics Neon was slipping and it was the motor mount, she replaced it and it no longer slipped. I'm not exactly sure what speed my tranny starts to slip but it's around 20-30 mph. I have yet to change the motor mount. My tranny also won't reverse until the fluid is warm it's a pain in the ass problem.

[Dirk Albring]

Thanks. I'll have to take a look at the motor mounts and see their condition. I think there's only three of them. I'll have to check it out in my Hane's manual. Too cheap to afford a Chiltons.

[denisond3]

I can NOT imagine how the motor mounts could be any part of this problem.
How many miles do you guys have on your Neons?
How long has it been since you changed the tranny fluid and filter?
I know there is a particular fluid used in Neon trannys, that is supposed to be better for them than Dextron III or IV. You can find its name by checking on older Neon postings.

[Dirk Albring]

Actually I changed the fluid in the pan and the filter not too long ago. In response to the post, a co-worker and I rocked the car and the engine moved all over the place. I checked the mount and the bolt that runs through the center of it was cocked downward rested against the inside of the mount. It looked bad to me, so I got a new one at Auto Zone and went to take out the original and broke two bolts out of three. I had to take out the radiator to get at the tops of them in order to sand off the heads of the two nearest the engine, since they were spot welded to the car frame. The frame that these two bolts run through is thin rusted steel; a very cheap design for sure. I'll use through-bolts when I put the new mount in. The other broken bolt runs through the thick, cast-steel half of the mount (the mount is actually comprised of three metal pieces), which is the major support for the motor mount. From the radiator side I tried using an impact wrench on it to break the welded nut so I could use a through-bolt and nut, but it's welded to a thick steel block inside of a square channel, which is part of the framework of the car. The broken bolt is threaded through the steel block and welded nut. I drilled a hole through it for an easy-out, but it ain't budging. I've been spraying it down with PB Blaster for two days now with no success. I have no ideas at this point. By the way...the mount was shot...bad. I can't wait to get the new mount in to see of the slipping is gone in the transmission.

[Dirk Albring]

Just an update...15 minutes after my last response. I was able to get the last broken bolt out with the easy-out. I'll let you know if the broken mount was the problem in a few days. Thanks for the responses.

[Dirk Albring]

OK, it's been a few weeks and I thought I'd let you know how the car is doing since I got the new engine mount in. The first week it seemed to be a definite improvement, but now I'm not so sure. It's back to slipping at 20mph. I have noticed that it happens at slow acceleration. If I tromp on it it seems to get through the slip, or at least it's next to nothing. Some day I'll figure it out. Any other ideas would be appreciated.

[k-townracer]

Originally Posted by Dirk Albring

OK, it's been a few weeks and I thought I'd let you know how the car is doing since I got the new engine mount in. The first week it seemed to be a definite improvement, but now I'm not so sure. It's back to slipping at 20mph. I have noticed that it happens at slow acceleration. If I tromp on it it seems to get through the slip, or at least it's next to nothing. Some day I'll figure it out. Any other ideas would be appreciated.

have u actually taken the tranny out of ur car and looked at the different components? there is a possibiblity it could be the clutch plate also known as a flex plate or fly wheel. if any of the teeth are broken or bent, that could be the reason for the tranny slipping.

[Dirk Albring]

No I haven't taken the tranny out. I dread the thought of that, but I would if I had to. It's been doing it since we got the car maybe 8 months ago.. Do you think it will get worse?

[denisond3]

Before taking the transmission out, I recommend you try doing the adjustment to the 'Throttle Pressure cable. It runs from the throttle pivot (at the throttle body) over to the transmission. Its buried under the battery box on mine, so the battery and box may have to come out. This cable is how the tranny is able to tell how 'hard' it should shift. It does what the 'vacuum modulators' did on the GM transmissions many years ago. The tranny would use a faster-more-forceful up-shift when the throttle is wide open, and a gentler shift when you are gently accelerating. This could explain the slipping when the tranny upshifts. I know the Neon service manuals from Chrysler Corp. will have adjustment instructions in them. In the Transaxle Diagnosis & Testing section of the manual, the mis-adjustment of the shifter cable and throttle pressure cable are listed for many conditions, including failure to go into reverse, and slipping in forward gears.
You should check both the adjustment for the gearshift cable, as well as the throttle pressure cable. Both of these adjustments may change with use. I had to adjust the cables on our old Dodge Omni soon after my teenagers got their drivers licenses. Coincidence?
If the adjustments dont help, I would be guessing the transmission has worn out clutches or a worn out band - in which case the problem will progress anyway. How many miles are on the car, and were they highway miles, or in town miles with lots of shifting)?

[Dirk Albring]

Thanks for the great advice on the cable adjustment! I'll try it. A guy at work told me to look for a vacuum modulator line on the tranny. Now I know what better to look for. The car has about 102k on it. Since I've gotten it (@ 95k) it's been mostly city driving...some highway, but it's always slipped at 20mph since I've gotten it.

[Mic1980]

i'm trying it to

[96SOHC]

dont these transmissions have bands that need to be adjusted as part of a transmission service? my Hanes manual says so...