Allison 5sp: blinking R and clunk in drive

02dirtymax

Member
Jul 3, 2009
149
0
16
Ohio
Hooked up to the camper with the '02 this weekend and got to the campground fine. Once there I tried to back up and had no reverse. The R was flashing and then I put it in D and touched the gas and it revved and clunked into gear. I drove to our campsite (found a pull-thru luckily) and still had no reverse and it would clunk into drive. Shut it off and tried it about 30 minutes later and it worked fine. I drove around the campground at idle speeds all day the next day and it finally did the no reverse and clunking into drive towards the end of the day.

I was researching my problem and found some mention of the F-trim solenoid. My truck has been suffering a very harsh TCC lockup the past couple months and I saw that is the F-trim also. I've also had some trouble with the truck almost wanting to die when putting it in gear after it has sat for a few hours.

Think this F-solenoid might be what I need?