I have an 82 GMC suburban with a 6.2 diesel, TH400 transmission and a NP265 transfercase. The last day of June we moved from Greeley Colorado to Southern South Dakota. Tems were as high as 107 that day. I had to stop several times to let the transmission cool. I didn’t want to burn it out. I was towing a Hyundai Accent (2002) on a Uhaul Car Dolly. The trans temp gauge registered as high as 210 degrees. If it got hot I would stop and let it cool. However recently I changed the rear axle, the pinion spider gears seized and exploded. I think I went from a 3.73 gear to a 3.08. However I am not certain. Certainly seems like it when I pass people at 30 according to the speedometer that used to pass me. However, recently it seems to have developed an occasional shudder as I accelerate. It’s mainly after alot of in town driving. I checked the brakes, serviced the rear end, and checked the fluid levels.
Ok, I came to a possible conclusion. Now I should say I am NOT a transmision mechanic. It’s just not my specialty. I’ve replaced a few in the past and repaired simple ones, but it’s not what I do. A few months ago I replaced the transmission filter and gasket. When I did, it seemed like the filter stayed a little loose. Now this transmission does have a deep pan. If the filter isn’t pulling right, could that cause a slow acceleration/occasional shudder? Mainly this problem only happens once the transmission has heated to almost the same temp as the engine, and only occasionally. Perhaps some Trans-X and a quick maintenance to see if it’s not getting as much as it needs??