akaDigger
New Member
- Joined
- March 7, 2022
- Messages
- 2
- Reaction score
- 1
- City, State
- EVANSVILLE
- Year, Model & Trim Level
- 1986 F-150 Base 5.0 EFI
Another no forward gears thread but possibly with a twist.
I procured a 1999 F-150 4x4 with a failed 4R70W transmission. It had good reverse but no forward gears. I dropped the pan and first notice the 1-2 accumulator has a broken spring. No tension when pushing up on it with finger pressure. So I pulled the valve body and the OD servo piston drops out due to broken retaining clip. The fluid was black. Full layer of black sediment in pan, normal looking creamy metal on magnet.
R&R of a transmission on this truck is no easy task (I didn't realize that when I started). But I got he transmission out. The forward clutch pack was toast. Reverse drum teeth and sun shell teeth were beat up beyond spec. Possibly very light pitting on the pump but no signs of scarring at all.
I see another 4R70W from the same year and model advertised locally so I bought it. Seller said it was from a wrecked truck and I have no reason to doubt him. Black fluid, with assembly line plug still in pan. Normal creamy metal on magnet. Very little (almost no) sediment in pan.
With transmission out, I blew out the cooler lines. I then flushed a quart of new fluid through and blew out again. Torque converter from "new" transmission was only thoroughly drained.
With installation complete, I added five quarts to pan. Torque converter got two quarts ahead of installation. Started engine and proceeded to add six more quarts. I shifted through the gears pausing momentarily at each position. Truck was up on jack stands all around. Forward and reverse gears seemed to engage firmly and propelled the rear wheels in 2H. I put the truck on the ground and backed to the end of my driveway. In drive, In drive I got a little scratch in gravel so assumed I was good for a test drive.
First time through the gears seemed to all shift smoothly. After a quarter mile, I pulled uphill from a stop onto the highway. I got a little shudder in first pulling out but then it seemed to shift well. I couldn't really count the shifts because of smoothness. I notice the tach doesn't change much when shifting. I believe I got into overdrive as the RPMs were about 1400 @ 55mph. (stock tire size). After a mile I slowed and made a u-turn. Accelerating, I got a neutral rev but then it went into gear and shifted as one would believe it should. I slowed to make my turn toward home and, when proceeding, got the neutral rev again. Then forward propulsion again. I slowed again to try first again and got no forward propulsion at all. Luckily I was just beyond a neighboring church with a large parking lot. I backed up to the lot, looped the truck and backed up the 100 yds home.
This morning I checked to see if it had any forward gear while cold. No, only reverse, When first started, drive would drag the tach down about 100 RPM but showed zero inclination to move the truck.
Since the transmission was allegedly propelling the donor truck, I am wondering if there is some other fault unrelated to the transmission itself. Could I have fried the forward clutch with only the one shudder and two one second neutrals?
I procured a 1999 F-150 4x4 with a failed 4R70W transmission. It had good reverse but no forward gears. I dropped the pan and first notice the 1-2 accumulator has a broken spring. No tension when pushing up on it with finger pressure. So I pulled the valve body and the OD servo piston drops out due to broken retaining clip. The fluid was black. Full layer of black sediment in pan, normal looking creamy metal on magnet.
R&R of a transmission on this truck is no easy task (I didn't realize that when I started). But I got he transmission out. The forward clutch pack was toast. Reverse drum teeth and sun shell teeth were beat up beyond spec. Possibly very light pitting on the pump but no signs of scarring at all.
I see another 4R70W from the same year and model advertised locally so I bought it. Seller said it was from a wrecked truck and I have no reason to doubt him. Black fluid, with assembly line plug still in pan. Normal creamy metal on magnet. Very little (almost no) sediment in pan.
With transmission out, I blew out the cooler lines. I then flushed a quart of new fluid through and blew out again. Torque converter from "new" transmission was only thoroughly drained.
With installation complete, I added five quarts to pan. Torque converter got two quarts ahead of installation. Started engine and proceeded to add six more quarts. I shifted through the gears pausing momentarily at each position. Truck was up on jack stands all around. Forward and reverse gears seemed to engage firmly and propelled the rear wheels in 2H. I put the truck on the ground and backed to the end of my driveway. In drive, In drive I got a little scratch in gravel so assumed I was good for a test drive.
First time through the gears seemed to all shift smoothly. After a quarter mile, I pulled uphill from a stop onto the highway. I got a little shudder in first pulling out but then it seemed to shift well. I couldn't really count the shifts because of smoothness. I notice the tach doesn't change much when shifting. I believe I got into overdrive as the RPMs were about 1400 @ 55mph. (stock tire size). After a mile I slowed and made a u-turn. Accelerating, I got a neutral rev but then it went into gear and shifted as one would believe it should. I slowed to make my turn toward home and, when proceeding, got the neutral rev again. Then forward propulsion again. I slowed again to try first again and got no forward propulsion at all. Luckily I was just beyond a neighboring church with a large parking lot. I backed up to the lot, looped the truck and backed up the 100 yds home.
This morning I checked to see if it had any forward gear while cold. No, only reverse, When first started, drive would drag the tach down about 100 RPM but showed zero inclination to move the truck.
Since the transmission was allegedly propelling the donor truck, I am wondering if there is some other fault unrelated to the transmission itself. Could I have fried the forward clutch with only the one shudder and two one second neutrals?
