Machining rear end pinion

Straightpipes

Straightpipes

Well-known member
I am putting a 10 spline 3.78 ring and pinion set into my 34' housing. The pinion will require machining. The 35' pinion bearing shaft is larger in diameter than the 34'. I am wondering about the fit of the pinion shaft into the bearing. Should it be a slip on or a press fit? Also, I believe that the gears may need grinding to fit into the housing. Has anybody here ever done it? Any comments or suggestions? Thanks
 
The pinion bearing should be a light press fit, although I don't know how much. If you can get the i.d. of the later bearing and then measure your pinion, you could replicate that difference when you turn it down. The o.d. of the pinion gear teeth will need to be machined down as well, just enough to fit through the hole in the banjo housing, I believe. I have also heard that some ring gears need to be clearanced on the outer edge so that they don't hit the banjo housing, but that's not for certain. You will need to use a 1/2" spacer under the pinion nut. There may be other considerations, I'm sure others will chime in. Good luck!
 
Straightpipes said:
I am putting a 10 spline 3.78 ring and pinion set into my 34' housing. The pinion will require machining. The 35' pinion bearing shaft is larger in diameter than the 34'. I am wondering about the fit of the pinion shaft into the bearing. Should it be a slip on or a press fit? Also, I believe that the gears may need grinding to fit into the housing. Has anybody here ever done it? Any comments or suggestions? Thanks
Click to expand...

I believe it was Richard EV8G who once posted a complete set of instructions on how this is done. You could send him a PM and I'm sure he would send it to you or maybe post it again here. If you can't get thru to him, send me a PM. I believe I saved a copy in my files.
 
If you measure an original late32-34 pinion shaft, there will be a difference between the diameter for the rear-most bearing (against the pinion gear) and
the same for the forward bearing. The rear bearing will be a press fit, but the
forward bearing will be a looser fit to allow it to move when setting the preload on the pinion bearings -like if it is set too tight, need to be able to loosen the nut and have the bearing loose enough to allow the setting to loosen. This difference is frequently overlooked when grinding the later pinion shaft down to fit L32-34 bearings. The later pinion shaft is also about 1/2" longer, so a spacer is required. An old 32-36 steering worm bearing upper race (the one that are not available new) is about the correct thickness and ID/OD. It is also necessary to shorten the L32-34 drive shaft to compensate for the extra pinion shaft (1/2"apx) length.

My experience with the 'new' gears (several years back) is that indeed there is a clearance issue between the reverse side of the ring gear and the LH housing. The original L32-34 gears have a relief in this area, while the "new" gears may not. (When you attempt to set the drag on the carrier bearings, you will discover this...) If the 'original' later gears have the relief, then there should be no problem, but if no relief, need to grind one.

The 3.54 pinion gear is too large to fit through the L-32-34 banjo housing hole;
not sure about the 3.78? EZ to check...
 
Thanks for the replies. All of this is helpful and very much appreciated. The 3.78 ring and pinion are a matched number set NOS. Ring is dated 6-36. The pinion gears will not fit into the housing as noted and will be ground. I may have a steering race down in the barn (somewhere) to use as a spacer.
This is for my 34 pickup. I have an extra 34 rearend which I have disassembled. The plan is to make up the entire assembly and then do a switch in the spring so my truck isn't apart for long. Most parts will be useable as the rear seems to be in good condition.
 
There were two articles in the EFV8 club magazine in past years that told you all you had to do to put the later gears in the 34 bell housing. I cant remeber the magazine issues at the moment but have copies at home. send me an email and I'll send them to you.
 
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