The Stovebolt Site Forums The Shop Area Engine Shop When You Ask A Question On This Site.....

it shows everyone how little you really know. But, I have run into something I'm not sure of.

When measuring the distance between the inside of the rear spings on my 37 pickup on the front side of the current 54 car rear axle, I got a reading of 44". When measuring that same distance on the rear side of the current car rear axle, I got 44 9/16". How can I interpert that as to tell me where to place my spring perches on the 55 Chevy rear end I want to install under my 37 pickup? Do I split the difference? Or do I grind the perches to fit on the axle crooked?

Next, how do I determine the angle of the pinion without puting the new rear end under the truck, so I can set the perches at the right angle?

I feel like these are big questions that have to be answered before I dare touch anything!

Joe :rolleyes:

My guess is that the perches are straight on the axle but also that the springs are a little bit crooked on the perches. I'd place them the same as the current axle which is now working I assume.
As for the pinion angle it will be the same as the transmission/engine angle, just on a lower plane.

Yes indeed, you will have to grind the perches to fit the axle. The perches will have to be at the same plane as the springs or the ubolts will not fit. I just ground a little off of each side and they fit pretty good. I bolted everything up under the truck just where I wanted it (with all the weight on it) and welded the perches on. i don't see any other way to get it right. This will enable you to get the pinion angle correct. Good Luck with it.

Joe,

Just curious, how does the width of the '55 rear compare with the original? I've toyed with the idea of changing the rear end on my '40, but I'm not sure what rear end to use.
Thanks,
Steve

Shipwright -

I know that assembling the perches, u-bolts, etc. before welding and welding the the perches set up is the right way to do it, but I'm not a welder. That's why I need to figure it out before hand - if possible.

ndnchf -

Right now, I have a 54 car Power Glide (3:54 gear) under my truck and it fits fine. The 55 car Power Glide is actually 1 1/2" more narrow than the 54 car rear end, so I'm expecting a good fit. I don't know how wide a 37 rear end is. I dumped mine in the mid 80's and went to this 54 car Power Glide rear end. I've had no problems with it whatsoever, I just want to go to a T-5 and I have to go to an open drive line to do it. Hope this helps some!

Joe

Joe,

Its easier than that. Snatch the torque tube out of your 54 car rear end. USING YOUR ORIGINAL SPIDER GEARS, put the 55 car drop out member in the 54 car housing. Set your pinion angle with a bottle jack and the weight of the truck on the springs, stitch weld your pillow blocks in place and you are done.

There are plenty of mobile and welding fabrication guys that can come over and stitch it up for you. This should be a minium charge. However for a little more than the price of a guy coming over to weld it up for you, you could buy a 135 amp mig/flux setup and do it yourself.

Did you measure the sping perch distance on the 55 car rearend? A 56 car bolted up under my 54 and 52 cars and all I did was drill another hole for the spring locator bolt to center things up. You can buy shims in 2* increments if necessary.

Chris

Joe, measure the driveline angle on your starter housing and set the pinion angle accordingly.

4.3in84toy -

I asked the question recently here as to whether or not a 55 car pumpkin and the axles would slip into a 54 car rear end housing and no one agreed that it would. Are you sure that the 55 car rear pumpkin AND AXLES will fit a 54 car rear end housing? Or do I use the 54 car axles? That sure would make the job allot easier!!

I see what you're saying, bolt it up so the pinion angle self sets and weld it up to the original axle "clamps"! I guess you could slip the perches in there and use them, if you wanted to.

cletis -

I understand what you are saying. That's a very good way to establish the angle. Good idea!!

Thank you sir,
Joe

You must use the 54 axles with the 54 spider gears and the 55 third member.

All this has got me thinking. I have had a little vibration in my 37 pickup(malibu rear end) and think the pinion angle is to much. I don't mean to get off Joes thread here but seems like a good place. How do you set pinion angle and how,Cletis, do you find the drive angle of the starter, and why use that angle?? I have heard of "levels" with degree's marked on it and my nephew says they some some sort of "dohicky" at Freightliner.

Alvin -

If I understand Cletis' comment, you use the starter because it creates a flat spot front to back on the bottom of the engine at which to tell how much rise from back to front or fall from front to back the engine has on it as it sits in it's spot in the vehicle. The difference in that angle created by the rise or fall compared to a level surface is the angle the pinion needs to sit at.

I think that's right!

Joe

Your starter is parallel to your driveline. Therefore the angle of the starter housing is the same angle as your crankshaft and the output shaft of your transmission.

You can get an angle finder for less than $20 at Home Depot. To see pictures of its use go to my \'54 GMC web page and click on "transmission".

On Classic Truck Shop.com there's an excellent article titled Driveline Geometry 101 .

Chipmunk, go to Harbor Freight and get a angle finder. They are cheap and work pretty good.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34214

http://www.speedwaymotors.com/xq/aspx/display_id.2916/qx/Product.htm

If you have both axles out of the truck, set them upsidedown (spring perches up) on jack stands. Level the perches and read the angle of the pinion, then transver the data to the new axle! You will need the angle finder to get it right on.

I have read where you want the engine and pinion at the same degree of angle,(( example,engine down 1.5, pinion up 1.5)). Don't go over about 5 degree or you could get u-joint bind, somewhere in the 2 degree range is about right. Also you don't want a straigh joint, u-joints need angle to work correctly, the front one cancels out the rear one, each revolution the driveline speeds up and slows down each 1/2 turn due to the design of the joint. With one angle down and the other up, they cancel each other and it runs smooth, take away one angle, and you have a vibration, install to much angle, more vibration. Keep them with in 2.5 of each other and you are good to go.

Check out some four wheel drive sites and driveline sites, they both have good information on angles and joints.
Joe

Prior to reading all of the aforementioned material from cletis and Joe H, I have always been told that most driveline/pinion angles are around 2 degrees.

The angle finder makes it easy to find that 2 degrees.

Thanks guys,
Joe