Defender TD5 Rebuild

Started by grizzlychicken, April 18, 2020, 06:14 PM

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Enjoying your write-up! Any pictures of the chassis swap?


Yes John I'm in that category too!

James if you mean the hilux change I did take photos way back then and I think I still have them but it was pre digital back in 94 I think so will take a look. For rover pics are coming of the chassis after some more rambling!

I think I had already showed pics of the transmission gear that was stripped to the bone. To get there I first removed the transmission and transfer case. It was November in Canmore and there was no room in the garage (dam kids sports stuff!) so surgery happened in the driveway. After a few cold days of wrenching the transmission/transfer case combo ended up on my work bench in the warmth of my garage!

Both the transfer case and gearbox were covered with the regular oily muck that comes with a defender drivetrain although there seemed to be an abundance of oily crap accumulated on the transfer case in particular. I couldn't see a clear leak from the transmission antoigh the bell housing was coated in oil that I think had come from a rear engine oil seal.

So from there I ordered a transfer case rebuild kit from Ashcroft transmissions, a new input gear and since my plan was to upgrade the engine power some more I decided to up the high range gear ratio as I had to order the intermediate gear anyway. I also wanted to improve the on road traction control so also ordered an ATB limited slip diff for the transfer case.
All the parts arrived and I was pretty exited to put it all together. However when preping the transfer case for the bearings I realized that the bearing seats had been damaged by the collapse bearing...........shit.......I should have just ordered a rebuilt transfer case directly from Ashcroft! But I was committed as shipping was a killer for all these heavy things!

And Santa sent me a new transfer case shell.

I decided to call aschcroft just before this order as  I wanted to have everything I needed in one shipping cost.  After chatting with the owner, who is a helpful guy of few words, he recommended to change out the main shaft in the transmission as the splines often get worn on the output shaft which is another reason for possible backlash and loss of drive. I was also suspiciously the input shaft as it seemed to have excessive play and also the crankshaft bushing which, the shaft sits in, had significant wear.

So I ordered a rebuild kit for the transmission and a new shaft. Here we go!

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From there the transfer case rebuild went fairly smoothly. All new bearings, seals, the transfer case had the reinforced intermediate shaft seat that was an issue in my old case, an upgraded ATB limited slip diff, a higher ratio 1.22 gearset and a shiny clean exterior! And I ended up with what I think is better than I could buy from Ashcroft!

While I was waiting for all these bits to get here, since I had pulled the seats, carpet, floor panels etc from the car I kept just pulling things apart.....
It was then I decided to order a new chassis through the club along with a bunch of other bits. I had already sourced new doors, hood, and other bits I'll show as I put her back together but the chassis I feel is the core of the car and has to be right. So a galvanized heavy duty chassis was on its way. Why do I need a new chassis? Well usually most defender owners replace their chassis due to rust but once I stripped mine down I found a significant twist and sideways shunt. It must have been hit in the back corner very had at one point.
Fortunately we have a rental property in Canmore and the renters were moving out. So I managed to renovate the house to allow me to keep the heated garage! So the stripping process was on! Down to bare bones!
First though I picked up the new chassis. Unfortunately some of the brackets had been bent in shipping but nothing that a hammer couldn't fix!

The I took the new chassis to the powdercoater.


Oh it was a thing of beauty! Unfortunately it had rained while sitting in the yard which covered it with a thin film of dust. Just needed a bit of cleaning.
I decided that the color should be Matt black as I read somewhere that that was more of an OEM finish for a defender. In hindsight now though I think it would have been a little better in their standard more gloss black. That's just me being picky and I may still clear coat the chassis to gloss it up slightly and add another layer of protection to the metal.
Calgary powdercoating did an awesome job!

It was then time to take it home and set it up and start to completely strip down rover.

How to solo unload a chassis :)

And here comes the stripping.... um you know what I mean!

Bulkhead bolts were a bugger

And here is why I did the chassis change:

Stay tuned! More to come!

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You and Adam should have had a chassis swap party.  Although the rust on his made things a real pain. On the positive side, both of you now know every inch of the trucks inside and out.

Matt H

No Road Except For Land-Rover.


I don't think there's anything too special on a defender to make a chassis swap that difficult. From what I recall, all the bolts are relatively small and easy to access, they'll either unthread or break off. On a mining Landcruiser however, there are some massive siezed 1" bolts in 1/2" steel plate for the rollcage that I'm still fighting with.

I wouldn't have top coated the galvanized frame black though, I would have finished there. Heresy!


Thanks again guys. Yes I did chat to Adam on a few occasions about the chassis swap and was very jealous when he dropped by the garage to check on rover in his fully running defender with his new chassis!
So yes you can certainly do a chassis swap if you plan on not changing much else with your vehicle and can end up with a great running truck if it has good bones. As I was pulling things appart on rover I realized that there would be some deeper rehab needed including paint and body work. Rovers bones were a little brittle!

For example let's start with the bulk head. Removing this beast was a chore. The bolts attaching the bulkhead to the chassis were well rusted in placed and sheared off pretty quickly and needed heat and persuasion to get removed!

On assessing the bulkhead I knew it was commonly corroded as it was steel.  Looking at my bulkhead I didn't think it was too bad and certainly salvageable.

I sandblasted it at consolidated compressor to see how deep the rabbit hole goes.....

Then I asked the guys at high wood rod and custom to help out with some repairs. They did an awesome job!

And then prep to get it galvanized:

Covering the bolts with high temperature sealant helps with removing the galvanization after.

Then a few weeks later another thing of beauty! And only 100 bucks!

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Your bulkhead corrosion there looks pretty standard. Lots of rot is hidden by bolted dash and footwells, and needs to be addressed. Lots out there are in an unknown state, and haven't had the steel refinished.

You're lucky you didn't get a warp in the flat areas of that bulkhead during the heat of dip galvanizing. On an older bulkhead than yours, particularly with any welding patches, it would be worth the risk of galvanizing. I would top coat and paint that bulkhead though, unlike the frame.

I ended up spraying line-x bedliner on the inside engine-side of the refinished bulkhead on order to stop future abrasion/corrosion, it went together ok.


Galvanized bulk head and chassis....SWEEEEEEET!!!!!!

You can't go wrong with it....once you put it back together again it will just last and last.   Also makes a big difference in resale....if it ever comes to that.

GREAT JOB!!!!!     And the write up is very motivating too ;)
Cheers, Bill


Yes pretty happy I went the galvanized route with the bulkhead. When I was tearing it down I knew it had to be addressed.

So I think Bill mentioned Johns excellent post on his heater upgrades which was an excellent read and a great job. I have a plan for improving heating on rover too. When I pulled the bulkhead appart I was quite surprised about the small heating aperture that was transferring all the heat from the heating box to the foot wells and windshield. I also realized that the heater core was on the smaller side for
That vehicle and that my heater blower fan was not functioning and when I did the fan control had 2 speeds- slower and faster.

So aperture size:
To start with the heater box has a pretty big output:

It is an Interesting design feature that they have a good chunk of that output restricted by a smaller
hole in the firewall:

So before I had the bulkhead galvanized I measured the size hole appropriate for the heater box outflow (see marked above) and cut it out. This should be a significant in helping air flow.

It doesn't look much but it was quite the chunk removed. At least an inch by 3 inches. So probably around a 20% aperture size increase.

Next in the plan was to upgrade the heate core. I had done quite a bit of lookin around and found what I think would be the best stock upgrade for my setup which is a new alisport upgrades heate core. Oh it's so pretty :)

The last part was replacing the blower motor. I was trying to find an option that would spin a a higher RPM that would fit into the stock housing but was not successful. I think I will add a step up transformer from 12v to15v which should be within the tolerance of the motor but should be a more reliable spin since the alternator should be between 13-14v it should increase the motor rpm slightly

Old heater fan rust. I think if I pulled I appart The bushings would be worn out.

So for better fan control I found a dutch digital controller that i think will allow way more placement
adjustability. n

Also keeps with the stock look.

I have the webasto took but this system doesn't really help move more air in the Vehicle as it just used the current ducting and us fan setup. It's great as a coolant heater and blockheater substitute.

So for extra heating I'm probably  going to add an airtronic d2 ( I know it's essentially 2 auxiliary heaters!) and likely mount it in the battery compartment.

Matt H

There are GM type HVAC blower motors that lots of folks use as an upgrade to the stock unit. I forget the exact part number but you are looking for a two wire unit, not a internally grounded unit.

The Defender source forum has lots of threads on this.
No Road Except For Land-Rover.


Lovejugs had a great idea....we took a blower motor and fan out of an early model GMC van and installed it into the existing fan housing, with only a small amount of futzing to make it fit.    I haven't enlarged the bulkhead hole yet but it's been on my mind for sometime now.    With just fan I've gained quite a bit more air flow into the cab and it's helped quite a bit.  I only need one coat in the winter now  ahhahahhahhah

Great right up here shane!!!!
Cheers, Bill


Thanks Matt. I did a bit of a search and interesting to see what everyone is doing.
Hey Bill I totally agree that you have to improve the air flow. There are no real specs on the blower motors for the defender as far as motor RPM or CFM.

My thought for excellent heat flow would be:
-improve the motor power
-improve the actual fan and how much air
The fan can display at a given RPM
-minimize the resistance to air flow from the heater box.

I do a bench test of my old blower motor by hooking it up to a battery(which I found out after had only 6v so need to repeat the test!) and marked a white spot on the fan. I then used the fancy iPhone slow mo feature to count the actual revolutions the fan made in 10 seconds by having a stopwatch in the background.
My data:
At 6.4v
Total revolutions 111
Total time 5 sec
Total RPM 1332.
So I will retest my old blower and compare it to my new blower for RPm at the same voltage.....when my battery charges up!

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Ok so my battery charged up and here are my numbers for 12v. The old fan motor and the new fan motor were pretty close at 46 revs in a second for the old motor and 48 revs in a second for the new motor so
Old: 2760rpm
New: 2880 RPM
This would be at aroun 12v or maximal voltage. With the alternator putting out 13.8v I would imagine that I would boost the rpm to around 3000

Old motor test:

New blower motor rpm test:

Now just have to figure out alternate motors RPM :)

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Ok so that's as far as the heater has got for now.

With stripping the chassis down, of course both axels, steering, suspension have to all come off and all the brackets from the chassis along with gas tank mounts and protective plates.  I also pulled off the bull bar and the running board steps.

The garage looked like a bit of a defender slaughter house when I was done with parts everywhere. It is going to be a jigsaw puzzle putting this thing back together!

So from here I started with the suspension components. After looking at the bushings I decided I needed to change these up which should also help with the on road ride comfort. So to the press!

Pressed most of the bushings out. I did read about burning them out but that was taking way too long! These will be replaced with poly bushings.

So now I had a pile of suspension components and steering components and they were in good straight condition but the paint was flaky and they had surface rust. So decided to do a powder coating run.

In the run I decided to tear down both axels too as they were straight but not pretty. While at it the brakes and brake disc guards needed to be done too.

And while I'm at it I may as well do the wheel wells!

It took about a week but when I got all the bits back I was super happy with how they turned out!

Now to get working on a rolling chassis!

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