Why won't my Buick Riviera shift, or why is the check engine light on when it shifts?

Short answer: If your Riviera barely moves forward but reverses fine and shows codes P0753 and P0758 (shift solenoid circuits), new solenoids are the first step. One 1997 owner replaced them with no change and was told the transmission needed replacing; a member said solenoid failure normally leaves the car in 2nd gear, so not moving at all points to internal clutches or the torque converter. On a 1995, the check engine light is harder to read because that year sits between the old and new code systems.

Symptom: The car goes into reverse but won't really go forward, with several codes stored. Or on a 1995, the ABS and Trac lights stay on and the check engine light comes on when shifting at low speed, though it drives normally.

What to check first

1. Read and write down every code. On a 1995, use the dealer or a shop with a capable scan tool; basic parts-store readers may not work.
2. Check transmission fluid level and condition. Dark, burnt fluid points to internal wear.
3. Test the shift solenoid wiring and connector before replacing parts.
4. If new solenoids didn't help, ask about internal clutches and the torque converter.
5. Get quotes for a rebuilt and a used transmission.

Likely causes

1. Failed shift solenoids or wiring. P0753 and P0758 point to the solenoid circuits.
2. Internal transmission failure. Members' conclusion when new solenoids didn't help.
3. Torque converter clutch circuit problem. P1860 was also stored on the 1997 car.

What it usually costs

On the 1997 car, the owner said the shop charged $405 for the solenoid work, and quoted at least $1,000 to replace the transmission. He mentioned junkyard units at $75–150.

Is it safe to keep driving?

No if it won't pull forward. A car that can't accelerate is dangerous in traffic. A check engine light with normal driving is less urgent but should be read soon. Verify with a mechanic.

DIY or shop?

Shop job for most owners: the 1997 thread notes the cradle must come down and the engine supported to remove the transmission.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists no recall for the transmission on the Buick Riviera in the model years we could check on 2026-10-26 (the recall lookup returned an error for 3 model-year queries). Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• NHTSA complaints: 47 keyword-matched complaints for Buick Riviera 1995–1999 (of 252 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-26; keywords: transmission, shift, gear, slip, check engine, solenoid). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 1995 Buick Riviera check engine light on Car Talk, an owner said the ABS and Trac lights stayed on and the check engine light came on when shifting at lower speeds, though performance seemed fine. Members asked for codes, and one said 1995 GM cars sit between OBD I and OBD II, so parts stores often can't read them and a dealer or better scanner is needed.
• In 1997 Buick Riviera Codes/Transmission Questions on Car Talk, a 1997 Riviera 3.8 supercharged went into reverse but wouldn't go forward, with codes including P0753, P0758 and P1860. The shop replaced both shift solenoids and the fluid with no change and quoted at least $1,000 for a transmission. Members said that points to an internal problem; one said failed solenoids should leave it in 2nd gear, so not going at all suggests clutches or the torque converter.

Quick tip

Solenoid codes are a reasonable first bet, but once new solenoids don't help, stop throwing parts at it and price the transmission work.

Vehicle focus: 1995–1999 Buick Riviera (3.8L V6, supercharged).

Safety / mechanic note

Don't drive a car that can't accelerate normally in traffic. Verify with a mechanic.