The Stovebolt Site Forums The Shop Area Driveline NEW!!! 3:55 Gear Installation Technical Article

Back in 2006, my pinion bearings failed and presented an opportunity to overhaul the torque tube and install new 3:55 ring and pinion.

During the install, I was frustrated with the installation instructions and took photos of each step along the way. I had always wanted to take the time and write a supplement to those instructions.

Well after 7 years of testing my work and many many miles of driving my truck, I have completed the article and it is now available in the technical articles.

Here is a link to the article in TECH TIPS:

I want to thank everyone that took time to review and help me correct errors or add technical information I didn't know.

Enjoy!

Want to thank Chris also. This was a good tip. Good photos and instructions. *My* first time to use the Bolt Bucket to layout the photos for a slide show "preview."

Thanks Chris. Hope it will be helpful to many.

Peg

Very nice, SWEET, Thanks

Thanks Chris for filling an important hole in the tech tips for AD trucks.

Question. What do you do about the speedometer? It would read wrong.

John

A ratio adapter is needed to re-calibrate the speedo.

Thanks! Nice with the pictures and comments.

Yeah I saved me a copy of the article.... I'm on the fence on whether to try this or not....

John

Now that I have my Saginaw in, I'll be adding the 3.55 gear asap! Thanks for such a great write up SWEET!

We didn't do a half-ton swap but something similar to the 1-ton. What a difference. As Chris calls it, "John has a 70 MPH smile on his face when he drives."

We are not the last person in the convoy anymore.

Peg

Sir Charlie is a trailer queen no more.....

An accomplishment I know John is quite proud of.

So am I!!!!

I have the original 4 speed tranny with the granny low first gear and a 4.11 out back. If I swap the 4.11 for the 3.55, how will it help me with my highway speed and gas mileage? Also, I know it will lower the engine RPM's, but do you know by how much? How much does it throw off the speedometer?

4.11/3.55 = 1.16 = 16% lower RPM

That would throw off the speedometer by 16%

Ratio adapters for the speedometer can be made for $75-$125

Only problem I see with the article is you need a buddy to do the project......

John

Actually, I think that is a bonus.

Two heads are better than one - double checking all the steps and adjustments. Also, some of the parts are unwieldy - two people make for safer work.

Does anyone offer a higher speed gear set than the 3:55? I plan to change the gears when the engine is swapped out in my 41 Special Deluxe. BTW, I hope no one is offended by my use of Stovebolt for my car instead of a truck. The info here is better than I've seen at any other site.

I got a set of 3.38 from Yukon for my 52 panel which I had put a 59 pumpkin in it. It whines some.....they made that set good but the second set was horrendous. I put the first set back in it. Just how my luck goes.

Just load 2 bails of hay in the trunk and drive around the block twice and you will be good with us. Posting pics of said requirements are mandatory however.
Welcome to The Bolt! (Pending delivery of posted pics, of course.)
Carl

Ha! Thanks, maybe one bale will fit. Will try to get a photo on here sometime or other.

Thanks, I'll check them out. There's a young guy who has a shop close by and he's really good. I'm going to let him look through my shop manual and see what he thinks of doing the work for me. There's also a good link here on stovebolt about changing one out. I'm a bit afraid of trying it myself.

Chris, I'm planning to do this same gear swap on my '46.
Where did you get the tools for adjusting the notched nuts to get R & P backlash? The GM Rear Axle Overhaul manual shows the tool as J-972. Thanks.

I hand made a tool using steel bar stock and a couple of bolts.

Very large 90* bent long nose pliers works great for the adjustment as quick one time solution.

Homemade tool with properly spaced pins is another option as mentioned.

Here is the. tool. I'll ship it to anyone who sends a $50 deposit refunded when the tool is returned (less shipping cost).

Maybe someone closer to you has a tool. Patrick's used to provide the tool in his installation kit, but he has become increasingly less reliable.

The tool is in Classic Parts' installation kit.

As a side note on the rear gear install kit.
My orginal rear gears were in good shape. I reused all the bearings. Having a selection of pinion shims and the spacer tool was all that was needed. Made the spacer tool from the pattern supplied on Deves.

Nothing like being in the middle of a post and the screen goes blank . "As I was trying to ask . In the tech article you(sweet) removed the brg, seal,and "deflecter'' .Well I did same only with 2 days of hell . The washer (deflecter) got bent a lot . What is it for ,do I need ? Could I just fix it up a little and put it back In with new brg. and seal ??? I do not know how to get a pic to you .

Last week I rebuilt the torque tube assembly by using this Technical Article and Deve’s website. Both of these resources are excellent and between the two I took the brave step of attempting this. Whitelightening: believe me when I say if I can do it - you can too. Not sure if I would have attempted this rebuild without SWEET’s good work.

Bout’ the only thing I would add is the front bearing lock ring can be tricky to slip into place. I took some extra time and ensured this ring was smooth around the outside edge, and I ensured the same for the torque tube. A very light coat of white grease on these two mating surfaces helped to let this ring slide into place with light taps on the pinion gear.

Congratulations, Tom

Patrick Dykes used to imply that he was the exclusive supplier of these 3.55 kits for Chevy/ GMC 1/2-tons. I thought it was his design. Do other parts sellers offer these gear sets? I wonder who actually makes them.

At one time, Patrick Dykes was the only supplier.

One of our members, Mother.Trucker, has also been a supplier for several years.

MT obtains his sets on his own, from a (foreign) manufacturer.

One photo below shows boxes of those R&P stacked to ceiling.

Thanks Tim for the info.

Question for those who've done the deed;
I see on some of the sites still listing the 3.55 upgrade gear sets that they "will not fit Canadian built trucks". Does anyone know why? I placed a call into Chevs of the 40's but he was unsure as to why there would be a difference.

On the Canadian trucks the carrier has the bolt pattern off by a hair so the ring gear does not bolt on .Now I used to have a picture of someone who drilled the Canadian carrier to fit the ring gear .If I remember right the holes were off very little and it did not effect the washers on the bolts that hold them together they fit in were they were countersunk.If anyone has the link to the article I would not mind the imfo as I am getting the itch to try this again .

Now who's idea was that to have different gear sets?? Thanks for the reply! Any other options (ie: "off the shelf") for these diffs?

See here:

https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1336168/re-canadian-specs.html

Much appreciated Curt!