Ring and Pinion Backlash after 4.10 install

[w_turner06]

Hi everyone, this is my first post here! But... I am having a problem with my 2014 3.7L. recently had a 4.10 ring and pinion installed to replace the 2.73. The car drives great, but there is a ton of slop when switching from drive to reverse and the other way around. A off-road shop did the install for $400 and also installed a one-piece driveshaft, and I think they forgot to check for slop because the factory one didn't do this. The problem has been there since the install, but 1,000 miles later seems to be getting worse. I obeyed the break-in period and changed the gear oil at 500 miles.

I will link to a reddit post I made with a video of the driveshaft shown when switching a few times from D to R and back. (WITH AUDIO) Thanks for any help! This looks like a great forum.

https://www.reddit.com/r/Mustang/comments/1dsb2yo/is_my_differential_ok_see_video_comment

 

[86GT351]

Who did the gear change?

 

[Juice]

No gear noise? The clunk is the only issue?

 

[w_turner06]

Who did the gear change?

Smith Offroad & Performance. The guy said he did a lot of ford 8.8 rear ends and other shops quoted me $1000+.

 

[w_turner06]

No gear noise? The clunk is the only issue?

As far as I can tell but I have heard a little clunking too in 1st gear. I will try to take another video while driving soon but I also have the Borla Atak cat-back so I probably wouldn’t hear anything. Here is a video with the same issue(also no noise)-

 

[86GT351]

Smith Offroad & Performance. The guy said he did a lot of ford 8.8 rear ends and other shops quoted me $1000+.

Simple. Take it back to have them look at it.

 

[JC SSP]

I second the motion. You paid for gear install and this is after they put them in.

If you had a standard drive shaft I would say u-joints but with that new 1-piece it has to be the carrier has play.

 

[w_turner06]

Simple. Take it back to have them look at it.

I will do that and update. I will have to work with the guy though on price because he said strictly no warranty. I did shoot him a text asking about the issue 2-3 days after the install, though, so I can use this as evidence that it wasn’t my fault. He never responded.

I would understand skepticism, because no one upgrades a 2.73 to a 4.10 in a V6 unless they are racing. But I haven’t done any racing so far, because it’s worrying me.

 

[w_turner06]

I second the motion. You paid for gear install and this is after they put them in.

If you had a standard drive shaft I would say u-joints but with that new 1-piece it has to be the carrier has play.

I will have to work with the guy though on price because he said strictly no warranty. I did shoot him a text asking about the issue 2-3 days after the install, though, so I can use this as evidence that it wasn't my fault. He never responded.

I would understand skepticism, because no one upgrades a 2.73 to a 4.10 in a V6 unless they are racing. But I haven't done any racing so far, because it's worrying me.

 

[GriffX]

I did this rebuild work only twice, so not an expert, but an incorrect backlash would led to some gear whine during driving. The play between rwd-fwd in the driveshaft is at least 20 degree, I don't see any issue in your video. Maybe the new driveshaft amplifies the noise now?

 

[86GT351]

I will do that and update. I will have to work with the guy though on price because he said strictly no warranty. I did shoot him a text asking about the issue 2-3 days after the install, though, so I can use this as evidence that it wasn’t my fault. He never responded.

I would understand skepticism, because no one upgrades a 2.73 to a 4.10 in a V6 unless they are racing. But I haven’t done any racing so far, because it’s worrying me. Going from 2:73 to:10 is irrelevant.

No warranty? Is he a legit shop? Why wouldn't he warranty? Anyone that won't stand behind there work would raise a red flag for me.

 

[Miker]

I did this rebuild work only twice, so not an expert, but an incorrect backlash would led to some gear whine during driving. The play between rwd-fwd in the driveshaft is at least 20 degree, I don't see any issue in your video. Maybe the new driveshaft amplifies the noise now?

This^^^

 

[w_turner06]

I did this rebuild work only twice, so not an expert, but an incorrect backlash would led to some gear whine during driving. The play between rwd-fwd in the driveshaft is at least 20 degree, I don't see any issue in your video. Maybe the new driveshaft amplifies the noise now?

I will ask a friend with a stock v6 to send a vid of his driveshaft and update.

 

[w_turner06]

No warranty? Is he a legit shop? Why wouldn't he warranty? Anyone that won't stand behind there work would raise a red flag for me.

Multiple shops said they wouldn’t do it with any warranty, and even they were charging $1200+. One place said $1600. But it’s dallas, and $400 seemed like a good deal, or $500 with the driveshaft.

To be fair, I should have realized this was something you really want warranty on, or at least asked to see photos of his gear tread pattern with colored gear marker (before it was put back together) and test for backlash.

 

[GriffX]

I can understand that they don't want to give warranty. They buy a gear set and you don't know in advance if it will make some noise despite everything is in spec and the contact pattern is fine. The Ford 3.73 were known to make some noise no matter what.
The driveshaft play is a sum of all tolerances, I think the biggest part are the spider gears of the differential carrier.