hard clunk when shifts

[Jeepdad]

When my E4OD, 302, F150 shifts from 1st gear to 2nd the truck clunks real hard. It only happens intermittently. Just started doing it yesterday.

Fluid level is good. Been told it could be rear speed sensor, or transmission.

Truck shifts at proper times, no vibration in driveline, runs smooth, but the check engine light comes on and truck will clunk when shifting.

Engine codes were 122, and 172. any thoughts? Jim

 

[smokey]

122 is a throttle position sensor low error
172 system to rich bank 1

 

[Skandocious]

Judging from the 122-- you've got a bad TPS. The E4OD takes inputs from the TPS for it's shifting patterns so it would make sense for these two events to coincide.

 

[flareside_thunder]

What he said ^^^^

 

[Jeepdad]

thanks guys, I erased all codes and triple checked the codes and it turns out it's the TPS. I tried the voltage test and got nothing so I'm going to replace the TPS.

I'm wondering though how this would cause the clunking? Any ideas?

 

[Skandocious]

These electronic transmissions take inputs from lots of sensors onboard in order to adapt shift patterns to the driving conditions. The TPS is on the throttle body and it detects how much pressure your putting down on the go-pedal. If you've got it floored then the trans needs to know so it can stiffen up the shifting a big to account for the higher RPMs. Of course the calculations that the computer is making are a bit more complex than that but that's the basic idea. Throttle position is important for when and how your transmission changes gears.

 

[Jeepdad]

thanks Skan. I'll replace the TPS tomorrow and I'll be a happy camper if this solves my problem.