Skip navigation

Gear Box upgrade

Post

Back to the top

Can a 1.8 carb drive a 1.8 GTI Gearbox?

Hi all can any of you wise and knowledgeable people advise me about gearbox options.

I currently have a 90 BHP 1.8 carb engine (code: EX) with the original corresponding gearbox.

This gearbox is now problematic; occasionally it won’t go into 5th and the other day it wouldn’t come out of 1st!

So it’s now time for a new gearbox. So what I want to know is can my car which is 90 BHP handle a Gearbox from a 1.8 GTI which I’m sure you know produces 112BHP.

I was planning on modifying the engine (cylinder head, cam, etc) before upgrading the gearbox to a GTI box but as my current gearbox is on its way out I have to do that first.

I know nothing about gear ratios so your advice will be greatly appreciated.

If a GTI box will work please can you tell me the codes I should be looking out for.

Thanks in advance.

Post

Back to the top

Gear Box upgrade

Hi, before you start spending lots of time and money changing gearboxes, are you sure that is the problem?
I only ask because the gear linkage is well known for becoming sloppy when the bushes get worn and refurbishment is a fairly easy DIY task if you have ramps and axle stands, there’s a guide on the main website. Also difficult gear selection can be caused by the clutch needing adjusting, again quite an easy DIY job, think it’s covered in the Haynes manual.
Your box is an 020 box, if you check the code on it you can look up the gear ratios online here

VW 020 5-Speed Transaxle Ratio Chart

Mk 1 Helios Campaign, 2.0 16v G60

Build thread here

Post

Back to the top

Gear Box upgrade

1.8 Gti box is the 7G code :-)


Sent from my iPhone using Tapatalk

Mk 1 Helios Campaign, 2.0 16v G60

Build thread here

Post

Back to the top
Agree with Mike,  check the gear linkage and clutch 1st. Also check there is oil in it, lack of oil can cause difficult changing or sticking in gear.

What code is on your clipper box? With the 1.8 EX engine you would expect the high ratio 4+E but my understanding is that the Cabrios had the GTI style close ratio box. (may have been the same box?)

Along with the 7G later 1800 MK1 hatches also had 9A (not to be confused with the 9a tall engine block) code GBs. Eariler 1600s prob had different again. Not sure what later GTI cabrios used.

The other thing to watch for mixing and matching GBs is that the driveshaft flange can be 90 or 100mm.

Finally, upgrading a carb engine to get the extra 20 odd horse power is expensive and involved, why not just get a GTI?

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

Post

Back to the top
When was the gearbox oil level checked as low oil will make the car pop out of 5th.

When was the gearbox oil changed as its best to change the oil every 40,000 - 50,000 miles and it's the sort of job that is easy to do but often over looked..?

Gear linkages as mentioned above are also worth changing/looking at.

Gti cabriolet use a AUG gearbox

All you wanted to know about the gearbox.

http://www.brokevw.com/


 

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

Post

Back to the top
Wow thanks for all the replies much appreciated.

I’ll try and answer your questions:

I’m pretty sure the Gbox is dodgy as the gear linkage bushes were replaced about 18 months ago. When the clutch cable was also adjusted. After this the gear change was smoother, but the problem of occasionally not going into 5th still occurred a couple of times after that but hasn’t recurred for a long time. The problem of it getting locked in 1st has only happened once a few days ago. This is obviously more serious and concerning.

The gear oil was changed less than 20K miles ago and I check the level and top it up myself regularly – this is one of the few things I can do myself.

Another thing that makes me think that the gearbox is dodgy is that when parked on a slope with the engine and handbrake both off but in 1st gear the car lurches forward slightly then stops then again and so on.

Thanks for the links to the Gear ratio charts etc, but as I say I do not understand what the numbers mean. I do understand ‘close ratio’ though.

Thanks for letting me know that a GTI Gbox code is 7G? Where would I find this code as the only codes I can find on my current box are 171919823 and 702 6112. I can’t see any 020 codes anywhere.

According to the ratio chart isn’t code: AUG just for America?

I think my drive shafts are 90mm.

The reason why I don’t want to upgrade to a GTI engine is mainly because I want to keep the car looking as original as possible (insurance is also lower), but I also know my way around a carb and can usually sort most problems with just a screwdriver. Mechanical fuel pumps also only cost around £20 and take 15mins to replace.  Therefore, although costly, upgrading the cylinder head, cam (and of course Gbox) to get the performance up are quick one-time, zero maintenance options.

I just need to know if my 1.8 carbed 90hp engine can drive a 112hp GTI box. I am looking for extra acceleration.

Thanks again

Post

Back to the top
The code is stamped under the gearbox/bell housing on a flat bit see pic. You need to crawl around on the floor and it may be covered in oil and muck until you wipe it clean. Until you get this the tables/charts and ratios won't mean anything. My understadning is that a late Clipper carb Cabrio already has ratios the same as a GTI box so if that is the case you won't gain/lose anything acceleration wise. You need to know what you've already got. Your engine can be made to work with any 020 box with increasing levels of difficulty due to differences in drive shaft cups, mounting points, clutch sizes, reverse light/MFA switches and speedo drives.

As said 7G is an early 1.8 hatch box, later 1.8 hatches ones used code 9A. Would think same age Cabrios were the same but not sure if after that they followed MK2 hatches or stuck with MK1 codes or something different again.

How will you know your replacement box is in better condition than what you already have? They are all now 30-40+yrs and 100,000s miles old.

The lurching forward could be a clutch issue or simply the compression of the engine as it is turned by the box instead of a running engine turning the box.

mk1 golf gear box code.png

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

Post

Back to the top
Sorry but I got the wrong gearbox code…
My 1988 GTi cabriolet came with a ACD gearbox fitted from new, I've had the car since it was 5 years old so I know it's the original gearbox.

With my gearbox at 60 mph in 5th gear the revs are at approximately 3,000 rpm, 70 mph is 3,500 rpm.

You can see your gearbox from looking underneath the car, picture of where to look in this link.

View topic: Gearbox 020 question - The Mk1 Golf Owners Club


I think so could be wrong as not sure what year your car is but most later cars had 100mm gearbox flanges and you will have similar gear ratios to a GTi car.

You should be fine running more power through a 020 gearbox as I’ve seen people run the 1.8 20v turbo engine with 150bhp through one but 150bhp is probably the limit but I guess it’s how you drive it that matters, fast gear changes on a cold gearbox will kill any gearbox in time… :thumbs: 

Last edit: by mark1gls


1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

Post

Back to the top
Thanks Early 1800, The numbers that are located as per your diagram are 171919823 and 702 6112 Which doesn’t seem to correspond with anything on the ratio chart. Are you able to identify it from these number? I can’t see any other numbers?

To clear things up my car is actually a 4 door GX (which is another reason why I don’t want a GTI). I replaced the 1.5 engine and box with those from a Clipper. So I am sure that the drive shafts are 90mm as they were not changed and are still the original ones from the 1.5 set up.

I take your point re the uncertainty of buying a replacement box, but if mine is faulty and may leave me stranded it seems that I have little choice but to take that risk and hope for the best as the cost of rebuilding my current box will be a lot more.

Thanks mark1gls for the code correction. I understand what you say about running engines more powerful than a GTI through a GTI box but my question is can I run a less powerful engine through a GTI box?

If anyone can identify my gearbox from the above numbers I would be very appreciative.

Thanks again

Post

Back to the top
Ah right made the assumption that it was a Clipper Cabrio being a EX engine.

Googling 171919823 comes up with the black plastic MFA/Reverse switch from the top of MK1 1.8 GTI boxes, the number is underneath the gearbox not on top?

Could you take a pic??

You can run a less powerful engine, as long as it fits (drive shafts, mounting points etc). The change to acceleration and top speed will depend on what you are going from and going to, which depends on……. what code box you have now and what code box you replace it with.


 

1983 Mars Red 1.8 Golf GTI
1987 Alpine White 1.8 Clipper Cabriolet

The trouble with doing nothing is that you never know when you are finished.

Post

Back to the top
You can check the size of the flanges with a bit of string wrapped around the flange.

Info taken from broke VW website

You can also measure the inner CV joint itself, and determine the size.

Take a piece of string and wrap it around the inner CV joint, right where it fits into the flange…. mark the string where it meets itself, so you know how far it is around the CV joint. Measure the string.

A bit over 11" (11.13) and it is a 90mm CV/flange.
Just under 12.5" (12.36) and it is a 100mm CV/flange.

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

Post

Back to the top
Thanks Guys,

It’ll take me a bit of time to take the pics and measurements as my car is on the road – no driveway and the weather isn’t too great.

But surely I have 90mm CV flanges as these were the original ones, unless 1.5s can also come with 100mm flanges?

Am I right in assuming that 90mm shafts are not interchangeable with 100mm ones?

So I’ll have to find a GTI box complete with 100mm shafts?

Thanks

Post

Back to the top
Don't quote me but I think if you get a GTI box or one with 100mm flanges then the main splined shaft is thicker. So you'd have to get to clutch disk to match. The GTI boxes are typically have shorter gear sets, your carbed 1.8 won't have any issues with it. It should be a touch quicker but cruise will be at a higher rpm. The best resources for info are already listed. You should be able to swap easily to 100mm driveshafts as well.

See my videos, Tom AFH

Post

Back to the top
Hi all, I hope you all are still monitoring this thread.

I still haven’t been able to get the GBox code for my Mk1 EX, but I came across this on Ebay:

https://www.ebay.co.uk/itm/Volkswagen-Golf-Mk2-gearbox-1-8-8V-PB/114648201921?hash=item1ab190bac1:g:4OYAAOSwGaRgDYzQ
As you can see it’s a box from a Mk2 with engine code PB.

The numbers on the Gbox are 020 301 107 H 12

Can anyone tell me if this will be a direct fit for my Mk1 with EX engine?

I know I’ll probably need the drive shafts as well so will these also be a direct fit for my car bearing in mind that the donor car is a mk2?

Your advice appreciated,

Thanks

Post

Back to the top
The Shafts aren't the issue., the 90mm and 100mm inner cups on the differential can be swapped out easily.

I got a hold of a TJ auto with 90mm Cups that I swapped the cups out for a 100mm that my Cabriolet had.

The issue is that if you have 90mm Spindles they won't accept a 100mm shaft as the out side joint is different.

90mm axles work in a 100mm spindle. but not the other way around.

What do Divorces, Great Coffee, and Car Electrics all have in common?

They all start with GOOD Grounds.

Where are my DIY Links?

Post

Back to the top
Mk2 Golf PB is basically a DX engine but with digifant fuel injection instead of k-jet.

It will fit your car, you will need to unbolt the gearbox mount as it's different from a Mk1 mount.

It's a bit hard to see in the picture as it's dark so I could be wrong but is it missing the input shaft inner seal, bush and rod? You could use your rod and it's worth replacing all the seals and fitting a new bush.

Something like this.
https://www.ebay.co.uk/itm/VW-Volkswagen-Golf-Jetta-Passat-Corrado-Vento-020-Gearbox-16v-8v-Oil-Seal-Set/112445735476?fits=Car+Make%3AVW&hash=item1a2e49c234:g:BvAAAOSwxeVefpqT

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

Post

Back to the top
Thanks Guys for continuing to monitor this thread.

Briano, please can you tell me what I would need to make the Mk2 Gbox work in my car. Much appreciated.

Thanks, Mark1GLS, Depending on what Briano advises I’ll ask the seller if he has the G.box mount and I’ll get a set of new seals as well.

Post

Back to the top
You can unbolt the gearbox mount from the one in your car and bolt it onto the "new " gearbox  :thumbs:

1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.

Post

Back to the top
so what are you after a full
set up gearbox shafts hubs
and linkages mounts from a
mk1 gti

Do not know a lot but willing to help if possible

1989 Sapphire Blue Mk1 Cabriolet KR
1985 Atlas Grey Mk2 GTI 2.0 ABF

Post

Back to the top
Hi Nicci,

Thanks for joining.

I just need a GTI gearbox to replace the non GTI Gearbox in my 1.8 Carb Mk1.

I came across this Mk2 box
https://www.ebay.co.uk/itm/Volkswagen-Golf-Mk2-gearbox-1-8-8V-PB/114648201921?hash=item1ab190bac1:g:4OYAAOSwGaRgDYzQ
and wanted to know what I would need in order to make it fit in my Mk1.

Can you offer anything better?
0 guests and 0 members have just viewed this: None.