JavaMan
OBS Enthusiast
I bought a used 96 Suburban 2500, with the 7.4L Vortec at 114k miles. According to the logs from the previous owner, the transmission fluid and filter was changed back in 2005 at 63k miles. I was worried about issues just changing fluid that's that old, so I did drain a gallon of ATF and refil it, waited about two months and 500 miles, then drained another gallon and filled fresh. I've got the new filter and fluid, just haven't had the time to change it yet.
I've noticed some 'slipping' when going up hills, first noticed this after the first drain and refill. Running 75 in 4th, it slows a little, so I push the accelerator a bit more, it shifts and hits the rev limiter, I back off and it shifts back to 4th, and I continue up the hill letting it slow a bit more, then I'm reaching the top of the hill, and no more problem.
I added a poor man's B&M electronic shift improver, aka a 10w wire wound resistor between the appropriate wires. Did this after the second drain an refill. With the switch on, it shifts firmer, which is great, I hate the mushy shifting. I speed up, 1-3 work great, it shifts to 4th, and a couple seconds later the RPM picks up, it acts like it's in neutral and slows down. If I let it slow down enough to drop back into 3rd, it shifts solid, but once I pick up speed again, it shifts into 4th for a couple seconds, then neutral again. I turned off the shift improver switch. It works fine again, 4th holds properly.
Any ideas on wht to do? Should I just do the fluid and filter change and see what happens? It was purchased "as is" because there was a fuel leak, so they knocked off $1000 from the $5500 purchase price; so no warranty. It only cost me $250 in parts to fix the fuel leak, so I'm still happy there.
I've noticed some 'slipping' when going up hills, first noticed this after the first drain and refill. Running 75 in 4th, it slows a little, so I push the accelerator a bit more, it shifts and hits the rev limiter, I back off and it shifts back to 4th, and I continue up the hill letting it slow a bit more, then I'm reaching the top of the hill, and no more problem.
I added a poor man's B&M electronic shift improver, aka a 10w wire wound resistor between the appropriate wires. Did this after the second drain an refill. With the switch on, it shifts firmer, which is great, I hate the mushy shifting. I speed up, 1-3 work great, it shifts to 4th, and a couple seconds later the RPM picks up, it acts like it's in neutral and slows down. If I let it slow down enough to drop back into 3rd, it shifts solid, but once I pick up speed again, it shifts into 4th for a couple seconds, then neutral again. I turned off the shift improver switch. It works fine again, 4th holds properly.
Any ideas on wht to do? Should I just do the fluid and filter change and see what happens? It was purchased "as is" because there was a fuel leak, so they knocked off $1000 from the $5500 purchase price; so no warranty. It only cost me $250 in parts to fix the fuel leak, so I'm still happy there.
