GT14 transmissions

[meadowfield 2,594]

I've been a little slow, and not paid attention - my first GT-14 1-0502 - serial 907068 has the following transmission - which we pulled apart 8-9 years ago.

 

Ports on the side and tow valve to the front - which locks tight.

 

 

My second GT14, which doesn't run, 1-0502 is serial 907028 has the following transmission.

 

Ports on the top and a tow valve that spins, but locks in one direction.

 

 

Both were manufactured probably in the same week in the same factory. I doubt they made them with different transmission - so which is original to the year?

 

Assume one has been replaced?

 

Any GT14 experts shed any light on this? 

 

 

[953 nut 55,771]

The second one looks like the hydrogear on my 1970 GT-14

[19richie66 17,522]

Mine is a 72 and it had the transmission with the valve and fittings on top. Can’t help you with the serial number as mine had one that was unreadable. It is a 1-0502 model though. 

[pfrederi 17,866]

Top one is a piston to piston hydro transmission  not correct for a GT-14.  Some one must have changed the input gear to make it work with a GT-14 transaxle unless they swapped out the whole rear end.  Piston to piston units first appeared in the 18 Autos and some no-names.  Then used in C series after that.

[meadowfield 2,594]

48 minutes ago, pfrederi said:

Top one is a piston to piston hydro transmission  not correct for a GT-14.  Some one must have changed the input gear to make it work with a GT-14 transaxle unless they swapped out the whole rear end.  Piston to piston units first appeared in the 18 Autos and some no-names.  Then used in C series after that.

 

I'm sure when I bought it, I had a manual that showed GT-14 with piston/piston. Also I thought later ones had it fitted - but i can't find anything. Whoever swapped it (I'm in the UK) did a good job if they did!

 

I've mentioned it loads of times ands no one ever corrected me - Help   am I going mad or did they fit both???

Edited May 14, 2020 by meadowfield

[pfrederi 17,866]

The first hydro were Wheel-a-matics.  Basically a Sunstrand hydro gear early version.  The service manual for it was pretty thin.  other than a couple of minor adjustments it was repair by replacement.  Next generation was the hydro gear used  in GT-14s, Chargers Broncos.  The service manual had a few more fixes but it was still pretty heavily repair by replacement.  I believe there is a TSB somewhere that talks about using Piston to piston to replace bad hydro gear units.

[meadowfield 2,594]

1 hour ago, pfrederi said:

The first hydro were Wheel-a-matics.  Basically a Sunstrand hydro gear early version.  The service manual for it was pretty thin.  other than a couple of minor adjustments it was repair by replacement.  Next generation was the hydro gear used  in GT-14s, Chargers Broncos.  The service manual had a few more fixes but it was still pretty heavily repair by replacement.  I believe there is a TSB somewhere that talks about using Piston to piston to replace bad hydro gear units.

thanks, so where did I get the idea from that it changed over during GT-14 production?  I must have dreamt it. Odd that no one flagged the pics of mine when I was plumbing the lift cylinder in.

That also might explain why there was no hydraulics... I had to take bolts out of the charge pump in order to pipe it! 
Hoping Garry chimes in and tells me I didn’t dream it all up...

[gwest_ca-(File Mod) 11,096]

1 hour ago, meadowfield said:

Hoping Garry chimes in and tells me I didn’t dream it all up...

Sorry not able to do that.

 

I have never understood the model numbering system that they used. The 90-2062 Sundstrand is shown for every GT-14 model.

Tried to record their use thinking the number represented the hydro and final drive combination but that turned out to be not true unless they recorded the models incorrectly.

 

Garry

[pfrederi 17,866]

Looking at the manuals section here for GT-14 even the last year of production used 90-2062  same as first year of production  like mine

[953 nut 55,771]

5 minutes ago, gwest_ca said:

Sorry not able to do that.

 

I have never understood the model numbering system that they used. The 90-2062 Sundstrand is shown for every GT-14 model.

Tried to record their use thinking the number represented the hydro and final drive combination but that turned out to be not true unless they recorded the models incorrectly.

 

Garry

I think you are correct Garry. The output gear of the 90-2062 from the Hydrogear to the transaxle is different  than the ones on Charger/Electro units. I did a thread about seven years ago on changing the gear out. Everything else on the two Sundstrand units was the same. I don't remember the number of teeth each one has. 

[daveoman1966 3,762]

The Sundstrand Hydrogear model for the GT-14 is 90-2062 and the 'drive gear' is 11-tooth.  

On the Sundstrand Hydrogear  models 90-2046, that same gear is only 13-tooth.

Here are the comparisons...

[meadowfield 2,594]

thanks guys, no worries Garry...

 

given I pulled it all apart and put it together and never noticed any anomalies, I'm assuming the swap was done by a dealer or someone very competent!

 

 

[meadowfield 2,594]

whilst we are on the topic...  a friend has another one of the rare GT14's here in the UK and it sounds like the differential has failed. Possibly the splines on the pinions - assume it is a 10 pinion from the era? but with longer axles?  I never split the diff on mine to look...