4L80E Replaced - do I have a gas or diesel TC?

[captedge_tn]

I just bought my truck a month ago, previous owner says he replaced the transmission with a used one. It's a 93 C2500 6.5TD w/4L80e, 210k - I drove it back home to TN from OR so it runs OK but the throttle response seems "mushy". I'm wondering if it has a gasser TC. How can I find out? Previous owner no help -didn't know if truck was a Turbo, didn't know to use diesel oil, didn't know -well, ANYTHING. I had to replace trans pan gasket and dipstick seal, so there wasn't any great care done with the tranny swap either. Ideas?

[JohnC]

Put it in drive and stand on the brake and throttle. If it goes much over 1800 RPM it's the wrong converter.

Most (all?) '93 6.5's had a turbo. Look for a thing that looks like 2 big snails joined at the hip above the right side valve cover. ("TD" = Turbo Diesel)

Read up here, join the subscription site and read up there. All will become clear.

[captedge_tn]

Rats - it breaks loose around 1700-1800. I guess that explains the "mush" and odd shifting. Thanks for the help though, guess I'm in the market for a new TC.

What is the stall speed of the diesel TC?

And yes, this site has already helped a great deal, as I learned about "air-lock/hot start" issues and how to solve them. A life saver in Montana and ND. Turbo? The previous owner missed the "Turbo Power" emblazened across the top of the engine- I just thought I'd ask him...http://www.thedieselpageforums.com/tdpforum/images/icons/icon12.gif

[JohnC]

Stall speed should be around 1700. There's an adjustable switch on the throttle that affects shift quality. Read up on it...

[rustyk]

That's the TPS - Throttle Position Sensor. I don't think that would have any effect on stall speed of the TC - but it does have an effect on TC lockup.

[Robyn]

The 4L80 was used behind the 6.5 as well as the 454. The converters are the same.

The only issue would be shift points if the TPS has been messed with.

When you say the throttle repsonse is mushy???
Does the engine rev up and the truck not go well or???

Most stock 6.5's are not a ball of fire.

Best

Robyn

[captedge_tn]

Shifting is not an issue - it shifts quite firmly under heavier throttle load and moderately under light acceleration. It shifts like I expect it to. But it requires more rpms than I would expect before it gets moving. After the truck gets moving the performance is acceptable. The TC also locks up as expected and does a good job of staying locked up over hills, etc. I was paying close attention to this as I towed a trailer on the 4k mile trip home. As there have been some threads about diesel vs. gas torque converters I started to wonder about what the difference was, and it didn't make sense that GM would put an 1800 stall converter(which I seem to have) on an engine which develops max torque at 1700, so this is why I asked. If it is true that GM put the same TC on gas and diesel engines, then I guess I would be interested if others have switched to a lower (1300-1500) stall speed to better utilize the low rpm torque of this engine. I hope to give my poor van a break and starting towing my motorsailer (6500lbs inc. trailer) with this so pulling the whole rig up a ramp is a consideration.