• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

3.54 Diff

Share this page

D

dphilippo

Senior Member
Offline
Now that a new batch of rear end gears are going out, I figured I would ask if there is anything that us new recipients should know about getting them installed. I was planning on taking the car and gears to a local driveline shop that does diff rebuilds and see what they thought about the job. Is that the way to go or does this project need a british car or vintage car specialist?

Also, I heard from someone at a british car show a number of years ago that the gears need to be broken in. Run on a stand for a while then short trips at low speeds. Is this good advice or overkill?

Is there anything else we should know about having this done?

Thanks all,
Drew
65 BJ8
 
I had mine set up by Fred Crowley when the first batch came around though I think any competent shop could do it if you gave them the workshop specs. They do need to be run in with short trips for the first 200 miles. Here's the procedure: https://www.reiderracing.com/rtech-break.php Remember to change the gear oil after the break-in is done.
 
Break-in is crucial. Can attest that the pumpkin will get pistol hot after even a short run until the gears are broken-in (imagine the shear force on the hypoid gears; that's why EP oil is required). The cool-down period between runs is important, and I'd do a couple off the ground first (make sure the car is stable on the jackstands). Change the oil at 500 miles or so.
 
Bob_Spidell said:
Break-in is crucial. Can attest that the pumpkin will get pistol hot after even a short run until the gears are broken-in (imagine the shear force on the hypoid gears; that's why EP oil is required). The cool-down period between runs is important, and I'd do a couple off the ground first (make sure the car is stable on the jackstands). Change the oil at 500 miles or so.
Click to expand...

Ditto that....I got a pair of the first gears for my '65 BJ8, followed the installation and break-in procedure and have loved the up-grade ever since. One of the best improvements I've made on the car.
 
Does anyone know the going rate for gear installation including new bearings, shims and such (not including the price of the gears)? I got a quote of $700-$900 from a prominent shop. It sounded fair to me but I want to double check.
 
Depends if that's a quote for the whole job--including pulling the pumpkin--or just swapping the gears.

What are their shop rates? At $70-90/hr that's 10 hours; maybe they're quoting pulling the pumpkin, which you can do yourself. A pro shop should be able to do the gear swap in 3-4 hours (pumpkin out), maybe less. If not, you might be be paying some for the 'prominent' part; when the first batch of gears came out Mike recommended a shop that would do it for $200 (you send them the pumpkin). But, that may have been only for labor (parts extra). If the bearings are still good you can re-use them, they're bathed in clean oil and should last a good long time; otherwise, the only parts needed are shims--maybe--possibly a spacer and a seal.

My dad and I did ours. It took us one long day but it's not something we do all the time, and we had to improvise some things. If you drive your car to the shop and have them do everything, you'll have less control over the break-in since you'll have to drive it home (though you could stop along the way to let it cool down). Do not jump on the freeway and drive 50 miles.

I'd like to hear the results from people that get the new gears installed. Mine has been fine for 30-40K miles, but it has a bit of whine; I think the pinion pre-load may have diminished. I heard from some people that had their gears professionally installed they have some whine, too. FWIW, my dad--who was a factory rep for Ford--said the early Mustangs had a lot of problems with rear-end whine, and I think my 2008 Mustang has some, too.
 
Bob,

That's for me sending him the center section alone removed from the axle. The estimate includes new bearings, shims and seals. Just looking in the Moss catalog, that's close to $400 of it right there, some of those bearings are $90 EACH! I guess that boils down to $300-$500 in labor.

I also have to choke down shipping back and forth from Wisconsin to California.

These guys have a good reputation in the Healey realm and they did my trans and overdrive. I felt their price to do that was fair (not a steal but fair) which is why I was thinking about them even though I would assume somebody more local could do it.

Walt
 
"I also have to choke down shipping back and forth from Wisconsin to California."

I'd give Tom Kovas a call at Fourintune, there's has to be someone in WI that he uses for that work.

Fourintune
W63 N147 Washington Ave.
Cedarburg, WI 53012
Ph: 262-375-0876 • Fax:262-675-2874
 
Your call, but I'd be a little uncomfortable with a flat rate quote on parts (flat rate on labor is SOP). You don't necessarily need 'new' shims--they don't wear--you just need the right shims to locate the ring gear. It's a distinct possibility one or both (or more) of the shims you have can be reused; we just swapped the shims we had and got a good adjustment.

Bearings are a tough call. If there's absolutely no sign of wear I think you can reuse what you have; like I said they are immersed in (what should be) thick, clean oil. I'm not convinced newer bearings are any better than old in quality--anyone happy with the new rubber parts?--and I suspect most are made overseas these days with who-knows-what QA. The shop might insist on new, which is not unreasonable, but they probably don't pay Moss prices.

If you think it's fair then go for it. I think I'd try to negotiate (maybe I've been watching too much 'Pawn Stars').
 
I got one of the first batch and have been very happy with it. As I recall it didn't get very hot at all during the break in.

I used Hooper's Rear End in Sun Valley, Calif. It cost a couple hundred or so to do the pumpkin. The guy said it was exactly like a Chevy Full Floating. I made copies of the Moss pages for the parts but he said it didn't need any parts.

Taking the pumpkin out is fairly easy. You have to pull the axle shafts a bit to pull the splines out of the diff.

On re-installation I followed Jim LeBlanc's advice and used belleville washers with o-rings on each bolt and it never leaks.
 
Thanks for all of the information everybody. That was very helpful. I got the gears last week, pulled the pumpkin this weekend and should have it back from the shop tomorrow.

Steve, what's the deal with the belleville washers and o-rings? I did a search on belleville washers but I couldn't find anything specific about using them with o-rings. Can you provide any more information about that? Just curious.

Thanks All,
Drew
65 BJ8
 
If we are talking about these going under the nuts that go onto the studs and secure the third member (pumpkins) to the axle housing I don't know why one would need o-rings as the paper gasket plus perhaps silicone sealant provides the seal.

I don't think this is an application where a Bellville washer is called for.
 
I used belleville washers because of my experience with Alfas where A-R used them as lock washers on aluminum parts rather than the split-ring washers as the former don't chew up the aluminum. VW as I recall used wave washers.

Jim LeBlanc had suggested putting o-rings under them as an extra proof against leaking. Maybe they don't do anything

I bolted this up using the paper gasket and a little hylomar back when I first installed my Lempert gears. The pumpkin has never leaked a drop from this joint.
 
An update on the new differential gears. I took the pumpkin out and took it to a local driveline shop. He rebuilt it and I reinstalled using differential silicone and the paper gasket. No leaks.

Bob had asked for feedback about any rear end whine in his post above. Mine sounds the same as before. No whine at all when I ran it up on the jack stands or on the ground. I've made it through 200 miles of easy driving break in and have started to drive more normally with the plan of changing the fluid at 500-miles.

What a difference. It makes my lower gears so much more useful driving on city streets and cruising at 75 feels like the car is just more relaxed. Thanks for all the advice. It's good to have the car back on the ground and driving great.
 
Back
Top