Thread: 88 RRC Auto Tranny question

The shift scale is in specifications, book three, years 86-89 of the RRC CD manual. ( And apparently 55 is about spot on.). I'm not quite sure what the other bit you're talking about is, but read up on where the auto is supposed to shift - that way you'll know the auto is OK.

i was thinking that maybe the new ecu (3.9) sent different signals to the auto than the old (3.5) ecu due to the fact the 3.9 is a lil more powerful and wont get bogged down by shifting earlier or doesnt it work that way?

Heehee the ECU in a RRC does not control the transmission, let alone much else other than a vague attempt at fuel injection. The trans is fully hydraulic.

Check your kickdown cable is connected to the throttle linkage and working properly. It is adjustable by shifting two nuts along the cable housing to adjust the cable slack out at idle. Sometimes one nut comes loose and your cable slips and no amount of throttle gets kickdown. Sometimes the cable breaks.

My 89 3.5 changes up & down @ exactly 77 kph.

Jeff.

Er, I think that is the TC locking , not a ratio shift. The 2HP22 locks at 77Kmh AFAIR.

A 3.9 4HP 22 locks at EXACTLY 85Kmh,which is a bitch if your speedo is 5Kmh out and you want to keep the TC locked in a 80Kmh zone.77 would be better but the ECU turns off injectors on override at 1500RPM, and I think they thought it would cause thumping, which TC locking does on override on a big hill where you gain speed..
Regards Philip A

Don't know about TC locking but it is definatley a ratio change as revs drop as in an up change. 77kph is GPS speed, speedo reads about 82.

Jeff.

The TC locking up will result in a drop in revs just like a gear change. In the 88 models it is bang on 80km/hr. The gear changes in these boxes are also set very low, mine used to be in 3rd by the time I'd gone 3 car lengths, results in constant up & down changes as you pull away from lights.