4l80e issues, advice?

[heavyjunk]

Hello all,
My 94 cclb 454 4l80e is having some issues, and I'm having issues finding a replacement......so Im thinking of fixing the problems in my original trans. When I bought the truck I forgot to check the trans dipstick and my test drive was slow and short, two dumb ideas.

When I finally checked the stick the fluid was brown . While driving it I noticed the 2-3 shift was slow and sloppy. and when it was real cold it would slip horribly until I let off the throttle and let it lock in gear. After it completes the shift I can pound the throttle and it wont slip at all. When I am barely on the throttle or when I'm really gunning it or at wot it shifts perfect.

Also, reverse takes 2 to 3 seconds to fully engage and sometimes it vibrates while engaging.

Every other gear seems fine and I've put a bottle of Lucas transfix in to prolong it a little more.

What do ya'll think might be going on here? Will new clutches and o-rings/seals and an HD-2 kit make her good again?

 

[DAC_CFH]

Have you changed the filter? I know its a silly small thing but a filter and fluid change might help. If you are able to down the truck for any length of time is the only time I would consider doing clucth and seals.. A complete tear down and inspection is more worth it.

 

[Tomcat71]

better be saving your nickles, 4l80E's are not cheap,I got lucky and found a rebuilt unit on ebay a guy had no reserve on and got it for 600 bucks, but usually its more like 1500.

 

[great white]

Sounds like a clutch and plate issue mixed with worn valves.....not uncommon in a high mileage unit.

If getting that deep, time for a complete rebuild.

Which is pretty much where you'll be at that point anyways.

Check for fault codes too. OBDII has more related to trans, but they can be revealing in OBD also.

 

[heavyjunk]

Yea, I haven't had any codes for transmission issues come up....I dont think; just a 13 and 43(?) maybe 33.......

I was really hoping a couple of fluid changes would clear it up a bit haha.

Anybody with experience rebuilding these units think I would have to change the bearings/bushings? I rebuilt my 46RE Mopar trans and only replaced one bushing. I'm not a huge fan of bushing replacement, and I refuse to let somebody else work on my truck.

 

[heavyjunk]

What really gets to me is that now that I need a trans for a '93, I'm finding ones out of 96's and 00's for dirt cheap, and cannot find any for mine for under 500 LOL

 

[great white]

Yea, I haven't had any codes for transmission issues come up....I dont think; just a 13 and 43(?) maybe 33.......

I was really hoping a couple of fluid changes would clear it up a bit haha.

Anybody with experience rebuilding these units think I would have to change the bearings/bushings? I rebuilt my 46RE Mopar trans and only replaced one bushing. I'm not a huge fan of bushing replacement, and I refuse to let somebody else work on my truck.

You just won't know until you get in there with a high mileage unit. Anything could be worn, but 4l80E's are pretty robust. It grew out of the TH400 and everyone knows their rep for being solid.

Another place they fail/wear is the valves. Sonnax even offers a repair kit for it as well as reamers and whatnot. TCC shudder, slipping, false neutrals, etc are the usual signs.

But if you have to get that deep into it, you're probably better off having a shop do it....

 

[heavyjunk]

Ok, so I got a wild hair and some money to blow, so I drained the fluid and pulled the pan, and was surprised to find that there was not as much junk in the bottom as I thought there might be....in fact there was only a light coating of metal jelly on the magnet.

I replaced the filter and added fluid and ran it with the tranny line off till clean fluid appeared, added a quart of lucas trans crap(I put that in every vehicle I have, even with new trannys), and finished topping it off.

Started driving down the road and about the 3rd stop sign I left the trans shifted so firmly from 1-2 I was scared, the 2-3 shift firmed up a lot and quickened up a lot, and the 3-4 shift was super firm too. Also reverse no longer lags before engagement. The more I drive the better it seems to get.

I plan on changing the fluid again in about 1000 miles if everything seems to work out like it is now.

So the question now is, how long will this last, any snowmobile riders out there know that they run friggin awesome before they blow, are trannys the same?

 

[heavyjunk]

................Not long.............

Took it out to get something from town and its shifting just the same as it was before, as if nothing had been done to it

 

[volunteerff21]

................Not long.............

Took it out to get something from town and its shifting just the same as it was before, as if nothing had been done to it

Mine did the same thing when I changed the fluid and filter. Fixed it for about 2 days. Looks like you might be in for a rebuild.