[Soph]

I just got back from a few weeks of offroading and was experiencing a vibration up around 70 mph. I had to service the double cardon on the front propshaft anyway, and inspected it in the process. U-joints looked good. Everything in order there, same with the rear drive shaft and Rotoflex.

I did find a nasty bit of lash in the front pinion and off the transfer case. Here's a video of what I am getting...

Lash - YouTube

The play in that front pinion looks just a tad bit excessive. I have a new set of 4.11 gears and bearings that will be going in asap so I am not as concerned about it. The play on the transfer case front output shaft I am mostly curious about. It too seems excessive, however I have never tested the play in that before so I am not certain what is normal and what is not. In reviewing the workshop manual this appears to have a roller bearing so I would expect that there should be some play there. If so, how much relative to what we are seeing in the video?

Any feedback here is welcome. I've got a fair bit of drivetrain work lined up for the vehicle over the next month or two...I'm about to put in a 3" lift, replace the rear rotoflex with a U-joint and install a double cardon rear drive shaft, and lastly install 4.11 gears front and rear and replace the TrueTracs with Ashcroft air lockers....So with all that happening I'm not adverse to getting into the T-case if need be. But I'm just not sure if that amount of play is normal.

Also worth noting the vehicle has 54000 miles. The last 15k includes some pretty aggressive wheeling though.

 

[Disco Mike]

Roves have always had some play in the drive train, very noticable when getting off the gas and going right back on. Would AI be concerned, yes, only if you have noticed it get worse.
Aside from that, if you are installing gears, and you are wheeling a lot, you really need to replace both diffs and install some kind of locker cause your factory 2 spider gear set up will not handle that for long as shown by the picture below. Also run an 85/q40 instead of the normal lighter oil once recommended bu Rover to slow the wear down.
If you have any questions, then we should talk so PM me your number and I'll call you.

 

[Soph]

Thanks for the info Mike.

Regarding the diffs, I am already running true tracs front and rear (along with Ashcroft HD axles). PArtly for the semi-locker functionality, but also for the very rreasons you mention...I didn't want to leave myself dependant upon that 2-pin setup.

The move the Ashcroft air locker is just to accomodate more aggressive terrain as my wheeling preferences evolve.

Appreciate the feedback on the movement in the t-case and diff as well.

 

[Disco Mike]

Curious about the type and severity of the trails you run? T.T.s front and rear are pretty good, I run a T.T. in the front with gears and axles and a detroit in the rear and I have never had a traction issue, same with a lot of the local people here in Colorado where we have "TRAILS".
I think it would be hard to justify an air locker with the small difference you will get. Just a thought.

 

[Soph]

I just returned from Moab (I make a yearly trip there) and I am finding that on some of the tougher ledges, things like the Z-turn, Golden Staircase, few of the big ledges on Goldbar Rim near the overlook, etc) the TT's are not quick enough to lock up and grab. Basically what happens is the vehicle carries its momentum up the obstacles but the delay in the TT's locking up is allowing that memomentum to subside and the vehicle weight to start transitioning back before they lock up, which in turn results in a failed attempt.

Now, that said, the vast majority of the trails the TT's performs extremely well combined with the TC. Its a great setup. Its only these bigger ledges that are the issue. I don't have any videos of the failed attempts in question posted, however here's a look at some of the trailes from the last trip.

https://www.youtube.com/channel/UCX_-fc9qRpSujKnQMcvgK7g

Worth noting I don't pound the heck out of the vehicle in these situations. I'll give it 3 good tries, and if she doesn't bite and there's no optional lines to try, I just winch. But my plan is to do a bit more of a build up and see how she performs.

 

[Disco Mike]

If you are running synthetic gear oil, that will cause the T.T.'s to take longer to engage, always run a non-synthetic 85/140 for best results.
Videos were great.

 

[Disco Mike]

Curious, after looking at your video, what size tires and how much lift do you have?

 

[Soph]

That's good info on the gear oil, I didn't know that. I am running a synthetic currently so that would be a factor. I'm going to change that out and do some comparissons!

I've got a 2" Terra Firma lift in it currently, and 265/75R16 tires (31.5"). So nothing too aggressive. I have a 3" Rovertym lift in my garage that I am planning to install, and probably go to a 33" tire at that point. I do not think I will go larger than that though as I do not want to get the vehicle too tippy.

 

[Disco Mike]

Only because it is obvious that you like to play, and if you are going to 33's, might consider going lower on the gears to maintain some good low end torque when needed.

 

[Soph]

I've been planning on that bit as well. I have new 4.11 gears and new bearings waiting to be installed.

...the challenge now is just finding time to get all of this work completed.

 

[Disco Mike]

Have you ever set up a set of gears before, you may want to find a friend that has if you haven't.
Good luck with the projects.