# Differential swap **URL:** \ **Category:** GEM Forum\ **Created:** [August 16, 2015, 10:41am UTC](https://community.electricforum.com/t/differential-swap/5202 "2015-08-16T10:41:48Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![inspectorudy](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inspectorudy/32/540_2.png) [@inspectorudy](https://community.electricforum.com/u/inspectorudy)\ **Post date:** [August 16, 2015, 10:41am UTC](https://community.electricforum.com/t/differential-swap/5202/1 "2015-08-16T10:41:48Z")
I live in Georgia where the hills are pretty steep and with my 7.5 motor and the 14 inch wheels I am having motor controller over heat problems. Rodney told me that if I got a lower gear diff I would lose some speed but have better climbing potential and that might help my overheat problem. Are there any of you flatland people that want a lot more speed but are stuck with a low gear diff that you may want to swap for my high speed diff? I do not know what is involved, is it just a ring and pinion swap or the whole thing. I also have not found out what my diff is. I looked for the label on it but have not located it yet. It came in a 2002 3.5 hp, E285. Maybe someone on here will help us out. I also have a good 3.5 hp OEM motor that I took out when I got the 7.5 motor that I would like to sell to someone who might need it. It is just sitting in my garage and is of no use to me. ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [August 16, 2015, 11:17am UTC](https://community.electricforum.com/t/differential-swap/5202/2 "2015-08-16T11:17:16Z")
Rudy Early 2002’s had a 3.5 HP Motor and 8.9 gears Mid model year they went to 5HP and 10.35 Gear box. An 8.9 is optimal for flat ground. You probably have a 40 MPH+ Machine. The little hot rod puppy must fly. A good 8.9 is VERY desirable for a lot of people. I have one in mine with a R4F 7.5 HP motor. One other downside is that a T1 controller is much more sensitive to heat than a T2. For your application a 12.44 wil make a climber out of it. How ever prudence would be to limit your speed to 35 MPH Rodney ---
**Author:** ![inspectorudy](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inspectorudy/32/540_2.png) [@inspectorudy](https://community.electricforum.com/u/inspectorudy)\ **Post date:** [August 20, 2015, 9:14am UTC](https://community.electricforum.com/t/differential-swap/5202/3 "2015-08-20T09:14:07Z")
The GEM guy has a used diff from a 2002 4 seater for sale. Does anyone know what it’s ratio would be? ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [August 20, 2015, 11:01am UTC](https://community.electricforum.com/t/differential-swap/5202/4 "2015-08-20T11:01:56Z")
Early 2002 is 8.9 mid year up is 10.35 ---
**Author:** ![inspectorudy](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/inspectorudy/32/540_2.png) [@inspectorudy](https://community.electricforum.com/u/inspectorudy)\ **Post date:** [August 20, 2015, 11:15am UTC](https://community.electricforum.com/t/differential-swap/5202/5 "2015-08-20T11:15:45Z")
Thanks Rodney. I’ll as him what the time of manufacture is. He also has a T2 controller for $50 but says it is not returnable. I asked him if it was rebuild-able but he hasn’t responded yet. ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [August 20, 2015, 12:44pm UTC](https://community.electricforum.com/t/differential-swap/5202/6 "2015-08-20T12:44:59Z")
Rudy If it’s a late 2002 it’s a 10.35. Not much of a difference from an 8.9. I have a set of gears to convert an 8.9 to a 10.35 for a hundred bucks. Whats the story on the T2 Rodney