JayZ
New Member
Very hard jerk when shifting from park to reverse. Any ideas
hard shift 65 sport fury
- Thread starter JayZ
- Start date
Check the band adjustment. If it is set too loose, it will cause the rough shift. If the transmission has not been serviced in a while this would be a good time to do it and adjust both bands and replace the filter.
Also check your motor mounts for excessive play or breakage. Check you idle speed, if it is set too high that will also cause a rough shift. Sometimes excessive free play in the rear end will cause a rough shift but if that is the case you should be hearing a loud clank when the car goes into gear.
Dave
JayZ
New Member
Thanks Dave
Yatzee
Active Member
Hard shifts can be attributed to either the low/reverse band coming on too quick, a worn band, poorly adjusted band, too high of engine rpm's, too high hydraulic pressure or an issue with the accumulator not functioning properly. If there is too much slack in the differential gear engagement you may also get this type of result. The best thing, if it's not in your skill set, would be to go to a transmission shop for diagnosis only, not a rebuild. For the differential, you'll have to drop the drive shaft and rock the pinion back and forth by hand to determine excessive slack. Good luck as there are several possibilities that could cause your symptoms and I'd start at the differential's slack.
JayZ
New Member
Thanks Yatzee This is ALL definitely NOT in my skill set.
A primary reason for the P-R shift "hardness" is that the line pressure does not go through the "Accumulator" in the valve body as it does when shifting into "D" from "P". The accumulator is a chamber with a floating piston, floating against spring pressure. It provides a cushion against the fluid pressure as it fills its particular "apply" circuit. This is the way they were designed.
On the earlier lock-up torque converter TFs, the torque converter clutch was applied when the trans was in "P", then "unapplied" when shifted into a drive range. With time, the "release" time took a little longer than when new, so it made for a harder shift into "R" or "D", as a result. A friend had a '76 Charger SE 360 which had that issue. Chrysler warranty bought a new trans assy for it, which did the same thing as it got some miles on it. "Part of the breed", it appears. The shift from "P" to "R" on my '80 Newport is harsher than any of the TFs in my other cars.
The ONLY time the "P" to "R" shift is "soft" is upon first "P" to "R" shift in the morning, if done immediately after the engine fires. Converter drainback is an issue as the front pump re-fills the converter after sitting over-night. Back then, this happened after the OEM-production factory-fill fluid was changed. The factory-fill fluid was a multi-vis fluid, which flowed easier when cold. Using the later Chrysler fluids, approved for earlier TFs, are supposed to be multi-fix, according to our former Pennzoil rep.
For good measure, before you re-check any adjustments, put some trans cleaner in the fluid and run it a while, then drain and refill with new fluid and see how things go. Sometimes, the new fresh additives can soften older seals and such, if that might be an unseen issue. Then, play with the adjustments, but as long as every thing is functioning reasonably well, adjustments might not make any difference. As long as the bands and clutches fully apply with no slippage now, an adjustment might be meaningless, as the old Chrysler service manager told me one time years ago. I suspect that if an adjustment does make a difference, presuming it used to be adjusted correctly years ago, you probably need to plan on a rebuild with new frictions, steels, and band.
AND, of course, make sure the engine idle speed is not too high! That just makes any designed-in issues with line pressure in "R" worse.
CBODY67
On the earlier lock-up torque converter TFs, the torque converter clutch was applied when the trans was in "P", then "unapplied" when shifted into a drive range. With time, the "release" time took a little longer than when new, so it made for a harder shift into "R" or "D", as a result. A friend had a '76 Charger SE 360 which had that issue. Chrysler warranty bought a new trans assy for it, which did the same thing as it got some miles on it. "Part of the breed", it appears. The shift from "P" to "R" on my '80 Newport is harsher than any of the TFs in my other cars.
The ONLY time the "P" to "R" shift is "soft" is upon first "P" to "R" shift in the morning, if done immediately after the engine fires. Converter drainback is an issue as the front pump re-fills the converter after sitting over-night. Back then, this happened after the OEM-production factory-fill fluid was changed. The factory-fill fluid was a multi-vis fluid, which flowed easier when cold. Using the later Chrysler fluids, approved for earlier TFs, are supposed to be multi-fix, according to our former Pennzoil rep.
For good measure, before you re-check any adjustments, put some trans cleaner in the fluid and run it a while, then drain and refill with new fluid and see how things go. Sometimes, the new fresh additives can soften older seals and such, if that might be an unseen issue. Then, play with the adjustments, but as long as every thing is functioning reasonably well, adjustments might not make any difference. As long as the bands and clutches fully apply with no slippage now, an adjustment might be meaningless, as the old Chrysler service manager told me one time years ago. I suspect that if an adjustment does make a difference, presuming it used to be adjusted correctly years ago, you probably need to plan on a rebuild with new frictions, steels, and band.
AND, of course, make sure the engine idle speed is not too high! That just makes any designed-in issues with line pressure in "R" worse.
CBODY67
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