i just got the repair sleeve to try to repair my forward clutch drum, but i am a little concerned that the input shaft could be undersize now that it is worn out the drum. trying to be clear im talking about the rearward part of the input shaft with 2 seals close together at the end of the shaft. it looks a little heat treated but doesn't look like it's worn undersize. i need to know what size it's suppposed to be stock and all i can find online are the diameter of the input shaft on the front side not the size that gets damaged all the time. my dial caliper measures mine at .855" aka 21.65mm anybody know what stock size is?

 

I don't have the dimension you ask for. I hardly ever see a worn shaft. I would order a re-sleeved drum from WIT and install the TransGo Hi-temp ring kit.
Drum part #34554EA, ring kit T34165ED
Personally I like the peek rings on the center support...

 

of the various stock, FTI 300m and sonnax aermet inputs on the shelf i get between .850 and .853

 

hey thanks man! appreciate your time! yeah i was getting .855 inches so i think my input shaft may be okay but i've since decided to get a hardened input shaft and input clutch drum from ebay and make the trans stronger while it is apart. I know i wanna port the heads and put a cam in, i don't know if my truck will ever see a turbo or heavy hauling but one or the other will probably happen, and the hardened input drum with cutback for extra bearing clearance is pretty sweet, less friction and .01% fuel savings will pay for itself in the long run right? haha.

 

I push a billet input on nearly everyone. They are weak compared to stock turbo400 metallurgy. The stock input where the splines that go into the turbine of the converter are weak and will fail under heavy towing especially if you have the TCC lock up set to PWM and come on and off all the time as per stock.

I think the two main things that get overlooked causing wear in the forward drum sealing surface are the condition of the stator bushings in the pump, and the alignment of the stator tube to the pump cover itself. Mishandling can easily knock the tube off axis. Inspection of the base of the stator tube where its interference fit into the pump cover, and reseating it fully in a press as needed.

 

thanks truck dog. your right im also disappointed in the trans design of support for the input shaft. the one i bought burned the bushing on the overdrive planet and allowed the tip to wobble in the forward drum, machine shop installed the repair sleeve and i got a used planet from ebay so i think ive gotten that problem straightened out. but my reaction carrier was dragging on the reverse band, tried multiple times to stretch the reverse band to prevent it from dragging, spinning backwards immediately locks up reverse band but forward still dragged sometimes, sometimes it stopped for a while after i stretched the band but it kept coming back so im sanding down the raised boses in the rear of the case to give my reverse band room to expand and prevent drag.

 

it was more of a turbo400 issue with those lugs moving, but I suppose it could happen to a 4L80e as well. apply red locktite and bop them back outwards just maybe .050 proud of the leeward side of the pin