HD Hydromatic? or HD Heavy Duty?

[Locomoko]

Hello Neighbors

I am rebuilding my 4l80E & installing a Superior shift kit. The kit references "HD" in a few parts of the instructions. Since Superior is closed over the weekend, I am curious if any can steer me clear of this confusion factor.

Does the HD mean hydromatic (4L80E is hydromatic) or does it mean Heavy Duty, which I don't think my K2500 Suburban is. :confused:

Thanks Stuart

[DmaxMaverick]

Your 4L80E is not a "Hydromatic". The "E" designates electronically controlled (the "L" is Longitudinal, 4 is # of gears, 80 is the series). The Hydromatic trannies are designated as "TH-###" (Turbo-Hydromatic, more specifically), and are hydraulic/mechanical (and sometimes vacuum) controlled. The TH numbers don't designate operation, just the series of the tranny.

The HD in the kit is probably Heavy Duty (but could be anything the mfg says it is), but isn't HyDromatic. If it is, it's the first I've ever heard of it.

[Locomoko]

Thanks for the info... Yea, that makes sense, what threw me off the track was the stamping in the side of the case "Hydro-matic" and the yellow ID tag on the side says Turbo Hydromatic. Oh well, when I got the 2nd sheet of instructions back from the machine shop who was pressing some bushings for me, I could see the HD meant "heavy duty towing".

BTW, the rebuild seems to be going OK. I am in the re-assembly stage now, each drum pack has been done and the bushings needing replacement have been changed. I had to purchase a teflon ring install kit (ouch) which I will put on e-bay afterwards.

The broken part was the reverse piston, which could have been done from underneath the vehicle, however, me thinking the worst and trying to save downtime I pre-ordered a rebuild kit w/video/ATSG instruction book and removed the tranny, so I went down the prim rose path unnecesarily. It is what it is.

At this point tough I am wondering if there are any adjustments to be made after install, or do I get off the hook because it is "E" electronic?

Thanks again for your knowledge. Stuart :)