Strange Transmission Symptom Related to Modulator Replacement

[mgramann]

Hey All,

I was having transmission shift issues, and looking around on here indicated that it could likely be the vacuum modulator. After replacement, the shifting issues were gone. I am now noticing a strange rattle from the transmission area, but I can't tell where exactly.

The reason I know it is related to the modulator, is after replacement, the vacuum line popped off, and the strange rattle stopped (and obviously the shift points changed as well.)

Upon reattaching the vacuum line, the noise started up again.

I've read about modulator adjustment for shift points, but is there any adjustment required during install?

 

[Warthog]

Sounds like the metal tube coming from the injector pump to the modulator is rubbing/bouncing on something.

Did you replace the rubber tube at the modulator? Was it the same lenght?

Check it and report back.

 

[mgramann]

The rubber tube was trimmed to be the same length, but I will check it out. I'll report back after the weekend.

 

[mgramann]

Update:I had to check on my lunch hour

Even in my business casual clothes I couldn't resist the temptation to check the metal tube for running, which meant climbing into the engine compartment. I don't know how I didn't get dirty.

It WAS the metal line contacting the firewall. I'm a little disappointed in myself in that I am fairly mechanical, but sometimes a person can be blind to the obvious. I bent the line slightly and it quieted down significantly, only touching occasionally. I will fix it permanently when I am more appropriately dressed for CUCV maintenance...

Thanks for the help Warthog!