greasemanicure
Well-Known Member
- Joined
- November 1, 2006
- Messages
- 168
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- City, State
- Burlington, NC
- Year, Model & Trim Level
- 1996 4X4 4R->5R mod
It's been too blasted hot to do much on our 96 Ex that I've posted earlier about no reverse and no low unless OD is turned off. In the mean time I've been trying to determine if the tranny swap I did a few years ago might be the root cause, or related. At that time the original tranny, a 4R44E lost reverse and then lost all forward gears. I rebuilt the VB with a lot of help from this forum, but that did not fix things. I found a tranny from a donor vehicle that was T-boned. It was not obvious at first but the tranny from the donor was a 5R55E from a 97 Ex. The 5R has a fourth shift solenoid that the 4R did not. I've been wondering if that could have caused a problem.
I've looked at the solenoid operation charts for the two trannies and have concluded that, unless the "software" in our 96 "knew" about the upcoming 5R and its extra shift solenoid, the tranny controller is ignoring the 4th shift solenoid, leaving it in a permanent "off" state. If that is the case, I believe that this is the scenario.
When the transmission control wants 1st gear it operates only shift solenoid 1. In the 5R, this will select 1st gear. So far so good. When the transmission control wants 2nd gear, it operates shift solenoids 1 and 2. In the 5R, this will select 3rd gear. WHOA! But 3rd gear in a 5R has the SAME gear ratio as 2nd gear in a 4R. OK. When the transmission control wants 3rd gear it will operate no shift solenoid. In the 5R, this will select 4th gear which has the same gear ratio as 3rd gear in the 4R. Still OK. When the transmission controller wants OD, it operates shift solenoid 3. In the 5R, this selects 5th gear/OD, with the same gear ratio as the 4R expects.
The 5R seems to have jammed in a second gear with a ratio between 1st and 3rd on the 4R. Maybe this would make for less abrupt changes from 1st to 2nd.
What I have as a question relates to the presence of a "CCS" on the 4R solenoid operation chart. I presume that is the Coast Clutch Solenoid. Is that correct? There is no similar solenoid on the 5R solenoid operation chart that I have. The operation table for the 5R shows that the coast clutch is inoperative with OD active and activated with OD off. Since I can only go forward if OD is off, might that indicate an issue with the operation of the coast clutch? OD on or off makes no difference to the big slippage in reverse. What is the 5R looking for to turn the coast clutch on or off? Is there a wiring diagram for what on the 16 terminal plug to the transmission connects to what on the inside? If not, I guess that I can buzz the wires when I next take the pan down. If it ever ****ing cools off.
Joe
I've looked at the solenoid operation charts for the two trannies and have concluded that, unless the "software" in our 96 "knew" about the upcoming 5R and its extra shift solenoid, the tranny controller is ignoring the 4th shift solenoid, leaving it in a permanent "off" state. If that is the case, I believe that this is the scenario.
When the transmission control wants 1st gear it operates only shift solenoid 1. In the 5R, this will select 1st gear. So far so good. When the transmission control wants 2nd gear, it operates shift solenoids 1 and 2. In the 5R, this will select 3rd gear. WHOA! But 3rd gear in a 5R has the SAME gear ratio as 2nd gear in a 4R. OK. When the transmission control wants 3rd gear it will operate no shift solenoid. In the 5R, this will select 4th gear which has the same gear ratio as 3rd gear in the 4R. Still OK. When the transmission controller wants OD, it operates shift solenoid 3. In the 5R, this selects 5th gear/OD, with the same gear ratio as the 4R expects.
The 5R seems to have jammed in a second gear with a ratio between 1st and 3rd on the 4R. Maybe this would make for less abrupt changes from 1st to 2nd.
What I have as a question relates to the presence of a "CCS" on the 4R solenoid operation chart. I presume that is the Coast Clutch Solenoid. Is that correct? There is no similar solenoid on the 5R solenoid operation chart that I have. The operation table for the 5R shows that the coast clutch is inoperative with OD active and activated with OD off. Since I can only go forward if OD is off, might that indicate an issue with the operation of the coast clutch? OD on or off makes no difference to the big slippage in reverse. What is the 5R looking for to turn the coast clutch on or off? Is there a wiring diagram for what on the 16 terminal plug to the transmission connects to what on the inside? If not, I guess that I can buzz the wires when I next take the pan down. If it ever ****ing cools off.
Joe
