Hi Need Advice Please

[Mikeandwendy74]

Hi I just bought a 1992 GMC Sierra 3500 Dually Diesel :). It has a NA 6.2 Here's my dilemma....the truck drives perfect in forward gears, but reverse is screwy, sometimes it hooks up and goes, sometimes it slips bad, sometimes it wont engage. You would never know it if you were driving forward it shifts beautiful. How can I tell which tranny I have and if I need to replace it, which ones are compatible? I can rip a gas engine apart from carb to block but I have never owned or worked on a diesel, I think im gonna like it. Any help is appreciated, thanks

[john8662]

If it's an auto and it's and overdrive transmission (being a 3500 series and a '92) I'd say that it's a 4L80E transmission, which was used starting in '91.

Sounds characteristic of a 4L80E, they are what I'd consider prone to reverse gear failure, as it's the same thing as a TH400 (with some more guts of course).

I think you'll like the diesel too!

Welcome!

J

[Mikeandwendy74]

Thanks for the tip, yep its a automatic 3500 with OD, you think I have to replace the tranny?

[Robyn]

Tranny is going to have to come out and be rebuilt.
Is this a 4x4 or 2WD?
Best to get onto it before it leaves you stranded needing a tow.
Not a cheery thing to think about I know.
If you are not up to doig the rebuild yourself find a good reputable tranny shop and have them go through it.
Be sure to have them do any updates available and always replace the converter.
Also the addition of a return line filter in the tranny cooler system just prior to the tranny is a must to prevent any crud left in the cooler from getting back into the new box.
Have your tranny tech install a Transgo shift kit, Now not any shift kit. Be sure to use Transgo.
Now I dont get anything from stumping their products but I have used their stuff for years and its good stuff.
There may be other recomendations that Transgo has to make the 4L80E better too.
Good tranny techs are tough to find so ask around before you drop your $$$$ at the first shop. The GM store/shop will most likely not be your first choice either as they generally do the stock replacement thing and dont get into the good aftermarket goodies.

Glad to help with more advice if need be.
I have had many years in the tranny business and will share what I can.
Best to ya

Robyn

[Mikeandwendy74]

Hi its a 2 wheel drive setup. Here's a question... I can rebuild motors, outboards, motorcycles engines, but have never tackled a tranny, I think I want to learn cus I like to fiddle with things :). How tough do you think it is and are there any good information books on learning how to do this. Thanks Also, how can I be absolutely sure this is a 4l80e tranny? I'll buy a book today to rip it down....

[Robyn]

Most of the bigger tranny supply houses have books available at the counter.
They are,for the most part very good.
A word of caution, one must be inventive when it comes to the special tools required.
I have a lathe and a mill sitting in the corner so making stuff is a snap.
Now seal installers and little doodads to make life easier are usually available too at the supply houses but can get pricey.
Read the book and lay all the components out in the order they come out of the box.
Remove the valve body and set it in the pan along with any little pieces such as check balls that come out of the channel casting and do all the work on thats stuff after you get the box done.
What generally happens with an auto is (unless there are broken hard parts)
The "Lip" seals in the clutch and band apply servo's get hard from time and heat and just wont seal and then the oil pressure fails to apply the clutch/band and the frictions burn up.
Carefully examine each clutch pack and band as you go.
A master rebuild kit from a major tranny supply co. is a great way to go.
Be sure to get the filter as it usually does not come with the kit.
A front pump bushing is a must ( The snout of the converter rides in it)
Get a new/ rebuilt converter too.
Your front pump is probably ok but look things over for bad wear and scoring.
Keep all the parts in the order they came out and not be turning parts over. This is important so parts that have worn slightly will be back where they were.
Replace all the thrust washers and thrust bearings too. The bearings are flat torrington type and the thrust washers are in many cases are plastic. If there is a choice of plastic or something better go with the better.
Some suppliers will have choices on product quality.
A complete bushing kit is available but most likely you wont need it.
Get a hold of trango's update and improvement recomendations for the 4L80E and see what they say. If the say do it, Make it so. These guys have been making auto's work better since the late 60's and really have their SH#$ together.
The 4L80E is a good box but if worked over right can be a GRRRRRReat box. There are a few areas that need some help and the transgo stuff will do it.

I did a 700R for my project with many of the transgo products and that little beast is wonderful.
Well Gidyupgo and see how things happen.
We will be waiting to help where we can
Robyn

[Mikeandwendy74]

Awesome thanks for the advice I thought about it today and decided without a doubt I'm going to rebuild it myself. Thanks again for the tips.

[Robyn]

If you hit a snag just scream and I will help as best as I can from here.

Robyn

[woodchuck]

I have been having a little problem getting an answer to my question from the people who sell the kit. My question is, what is involved in installing the hd2 kit into my 92 6.5 turbo 4X4 with about 30K miles on a GM Goodwrench Transmission. Do I drop the pan and remove the valve body and replace old parts with kit supplied parts or do I have to do modifications to the casting itself or what? I have rebuilt an automatic transmission once, many years ago, and it came out well, but I am much older and more conservative now. The truck is used mostly as day to day transportion, but also must pull our new 29 foot travel trailer, which is a bit heavier than our old no slide out 30 foot trailer. It is also a lot taller than the old one.

Thank you one and all for the help and advice.

[Robyn]

It can all be done from the bottom.
The detailed instructions will guide you right through.
Just follow them and mark each one as you do it.
Piece of cake
Read the instructions before ripping into it to be sure there are not any other items you need.
Robyn