Hi All, Earlier today I had to have my 1994 GMC Top Kick Box Truck (automatic w/ 3116 Cat) Towed about 50 Miles home. The truck was seemingly running well for my helper when he said all of a sudden it felt as though somebody put the truck in neutral while heading up a hill. The truck was on a 2 lane road with guard rails and no shoulder so he activated the hazards, put truck in neutral and set the parking brake and chocked the wheels to set out the cones. He shut the truck off and called me letting me know the situation. I told him to restart the truck and see if it had ANY gears....He did so and it seemed as though the only gear he had was reverse....No drive, 3 , 2, or 1 . Now here's the weird part....The truck, when in neutral acts as though it's n reverse ! (it acutally caused the truck to jump a wheel chock!). Anyways, the truck was towed to my house and I looked it over....no leaks per se. Fluid was a little low but not by a lot... Fluid looked Ok....not burnt. The truck has 425K mostly highway miles. Any ideas ?....Maybe a cable so some adjustment? (only reason I am thinking of cable is that I had to replace the parking brake cable earlier and maybe there is a cable working the tranny that could be out of adjustment or broken? Why would neutral act like reverse? The truck really doesn't "lurch" into gear even going into reverse....you have to give it fuel to make it go in reverse or neutral reverse. Any thoughts on where to but a good used or rebuilt tranny? (my helper can drop and replace trannies BUT the cable adjustment may be tricky).... think the trans is an AT 545 from the reading I've done....It was dark and rainy out so I can look at the actual trans tomorrow to see if it has an ID plate or something. Thanks in advance for any and all help. Andrew
If indeed you have a 545, sounds like a forward and second clutch issue to me. Reverse in neutral usually means a welded second clutch... IIRC. The 545 is very simple, any trans shop that can do an old Turbo 400 can handle one of these. I used to rebuild 7-8 per year. About 3 hours if you have parts on hand. Anymore most shops just do a factory reman because its cheaper than local labor. Check with you local trans shops... You might get lucky.
HI RZ, Thanks for the info....My helper and I have no problem dropping and installing the trans, the part that is slowing me up is getting it rebuilt or finding a good rebuilder..... I've had several trannies replaced or rebuilt over the years and never really had a good experience so far... I have gone so far as to looking into rebuilding it myself BUT I know there's a lot of small parts and things to watch out for... You gave me greater hope in getting it rebuilt by saying if you can do a TH400 you can redo this one....I just figured it would be super hard being from a bigger truck and (at least to me) not as well known as a TH350 or TH400 Thanks and hope to get this truck back up and running soon. Andrew
I just got a rebuilt one for a customer, was in the $1700.00 range. He didn’t want to wait for me to rebuild it. I used to rebuild one a month or so. Pretty simple if you have a book on them.
It's amazing how these things used to be bone simple, and they told you how it worked and how to repair it instead of taking it to an Authorized Dealership to screw it up. How did we ever get anything moved before overcomplication took over.
Just an update... couldn't find a good rebuilder that I felt good about so I ended up getting a $500 junk yard tranny from a bus... We got the tranny in and we are in the process of changing the filter and fluid (we waited to see if it worked before popping for new fluid and filters). The trans seems to work ....Knock on wood ! I am debating about keeping the old tranny and doing a rebuild on it myself or just turning it in for the $100 core charge....Decisions Decisions...