Join Date: Jul 2010
Thanked 6 Times in 4 Posts
4-3 Downshift issue on 700R4
I have a '93 Suburban with a 6.2L diesel and a 700R4 transmission. I originally pulled the transmission from a diesel 1984 C2500 Suburban along with the 6.2. I installed a governor kit to make the transmission upshift sooner shortly after the conversion on my 93 was complete (it upshifted too late and it held the gears too long). After the governor was upgraded, I have had no trouble since until now. Recently I have had an unusual issue with the transmission "neutraling" out on the 4-3 downshift. If I force a downshift with the accelerator, it will rev like I am in neutral. If I let off the throttle it re-engages 4th. If I pull the shifter into drive from overdrive it will immediately drop to 3rd. If I slow down to the automatic 4-3 downshift point (about 35 mph) it will drop to 3rd without a hiccup. The problem is just on a throttle forced downshift, and the transmission doesn't do this all the time, but it seems to be an issue when the trans is warm where sometimes it will work normally, and other times it will act like an imbecile. All other functions are normal, and it upshifts fine. The fluid is cherry red, but I dropped the pan to service the filter anyway, just to be safe. The inside of the trans is clean and there was no evidence of significant wear in the pan. If I use manual drive (manual 3rd) it drives seamlessly. In overdrive it performs normally as well, except for the 4-3 downshift, which is sometimes a 4-neutral downshift. Any trans gurus out there with an idea of what might be wrong?
1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
3.73:1 gears, THM 700-R4 transmission, and
J-code 6.2L diesel from a 1984 C2500 Suburban
1996 Ford F-150 4x4 300ci Inline 6 "The Argo"
327,000 miles and climbing
1992 Caprice Wagon 5.0L TBI "Enterprise-D"
Ah ha ha ha! I swear! Tractors is so dumb!
The Argo? That ridiculous pile of scrap metal!