New Differential Installation

Let me save you some time and trouble right up front by pointing out that the 4 flange holes for mounting to the driveshaft ARE NOT symmetrical i.e. a perfect square. They are actually a rectangular shape so the drive shaft flange will only mount up in 2 of 4 possible combinations. Normally this wouldn't be a big deal but when you've had the Nissan flange machined to match the Triumph driveshaft flange you're left with 8 holes in the diff flange.

I know it looks square but it isn't! The black lines are about 3/8" longer then the yellow.	Lots of combinations here. The yellow are the old holes and the pink are the new ones.

So..............BEFORE putting your diff up on to the car, take your driveshaft flange and mate it to the new flange and mark the holes with a dab of paint......ideally one color for the short holes and another for the long holes. You will be very happy that you did that. I had planned on doing it but I had a senior moment and completely forgot. As a result I tried to match the driveshaft flange to the diff flange while both were in the car and I was working alone. To make a long story short, I ended up removing the diff and attaching the shaft out of the car.

But first.........some diff installation "issues" that I had to deal with. Using my diff carrier, I was easily able to work the diff into position and bolt it in place. Then I noticed that the flange didn't clear the tunnel "tee shirt".......not good!

Definitely not enough room to attach the driveshaft without hitting the tunnel

So what do you do? Well..................you flatten the tunnel! Get the biggest C Clamp you can find......this one has a 6" opening......along with a big old crow bar and start turning! The irony is that there are guys with brand new RATCO frames that are having the exact same problem. Just the thought of using this technique on a brand new $3300 frame makes me cringe.

I was able to pick up about 3/4" using this "technique".

So that solved one problem but then I spotted another. The top of the diff was hitting the frame cross member that goes over the front mounting brackets. So it looked like I'd be doing a little work with the angle grinder.

Hitting up top	Yellow area gets ground down

Once I was finished making my "modifications" the diff was a perfect fit. Now all I needed to do was measure the driveshaft length and get my driveshaft shortened, welded and balanced. Remember that I'm doing the diff upgrade along with the Toyota 5 speed conversion. Up until very recently Herman's 5 speed instructions only called for collapsing the driveshaft and using a locking collar that comes with the 5 speed kit.  Now Herman wants the driveshaft shortened and welded to eliminate the slip in the driveshaft. There will be a more detailed explanation of this in the 5 speed section of my work. The end result was that after talking to FleetPride which is a national chain, I elected to have them build me a new solid shaft that measured
26-5/8".

The new solid axle

and all attached to the differential ready to be installed.

It would have been much easier to install the diff, then slide the driveshaft in and use a telescopic magnet to guide the bolts into the flange.............but, I didn't mark the flange holes as mentioned at the beginning of this page. So I ended up working this into place as a unit which isn't that difficult to do.

Next up was installing the axles and bolting them to the diff. Make sure you read Richard's directions on the use of the two springs that come with the kit.

One long, one short.	The short one goes in the driver's side axle

Now, the only problem I had was that Richard's instructions said to assemble the two halves and slide them as a unit through the trailing arm. But there was no way my rubber gaiter was going to fit through the trailing arm. Maybe newer ones are more flexible and can be compressed but mine wasn't about to fit. So on the driver side I loosely attached the axle flange to the driveshaft flange and then slide the other half of the axle through the trailing arm, eventually lined up the splines and got it all together. On the passenger side I did it basically the same way except I left the inner half of the axle loose, got the splines together and then attached it all to the driveshaft flange. Neither way was easier or harder then the other way.

Driver side being assembled.

I did have one axle hub hole binding on the trailing arm bolt so, following Richard's directions, I went up one drill bit size and enlarged it.

One last word of advice...........leave the bolts to the Goodparts front mounting bracket loose until you have it all connected to the driveshaft. That way you have some free play to get everything lined up and clear of any obstructions.

These connect to the front mounting posts. Leave them loose until everything is lined up.

Next Up........hooking up the 5 speed.